Category How to Find the Apollo Landing Sites

Apollo 17

Crew: Commander Gene Ceman CM Pilot Ron Evans LM Pilot Dr. Harrison Schmidt

Command Module America Lunar Module Challenger

Accomplishments: Last Moon landing. Longest lunar stay of 74 hours and 59.5 minutes. Returned 243 pounds of lunar samples.

Apollo 17

Fig. 9.1 Apollo 17 Insignia. Courtesy of NASA

Apollo 17

The Apollo 17 landing in the Taurus-Littrow Valley was the last Apollo mission, with Apollo 18, 19, and 20 terminated due to budget cuts. As of this writing, Apollo 17 proved to be the last time man set foot on the Moon. Apollo 17 was the final J-type mission, distinguished from the previous G – and H-series missions by expanded and improved hardware, a larger instrumentation package, and extended exploration and sampling range using the Lunar Roving Vehicle, or LRV. The pri­mary objectives of Apollo 17 were threefold:

• Conduct geological observations and collect samples of the Taurus-Littrow region for data of the specific area. The Apollo 17 mission collected Taurus – Littrow information for comparison with geologic data from the previous Apollo mission regions. This objective was aided with the extended range provided by the LRV. The LRV carried onboard two experiments, the Lunar Traverse Gravimeter (LTG) and the Surface Electrical Properties (SEP) experiment.

• Deploy and activate a new version of the Apollo Lunar Surface Experiments Package, or ALSEP, that included five experiments not previously deployed by the earlier Apollo missions. The ALSEP included a heat flow experiment; lunar seismic profiling experiment (LSPE); lunar surface gravimeter (LSG); lunar atmospheric composition experiment (LACE); and lunar ejecta and meteorites (LEAM).

• Conduct lunar orbiting experiments from Apollo 17’s Service Module, including a lunar sounder, infrared scanning radiometer, and far-ultraviolet spectrometer.

Apollo 17 was the first and only Apollo mission that included a scientist as part of the crew. Geologist Jack Schmitt served as the LM pilot, with veteran Astronaut Gene Cernan serving as the Apollo 17 Commander and flying the LM. Both Gene Cernan and CM pilot Ron Evans received extensive training in geology and lunar science, with Ron Evans concentrating on visual recognition and observation of geological features from long distance.

The original crew assignment was Gene Cernan, Ron Evans, and Joe Engle, a former X-15 pilot credited with 16 X-15 flights. Three of Engle’s X-15 flights exceeded the altitude of 50 miles which earned him astronaut wings prior to his joining Apollo. The normal NASA practice was to have the backup crew of a mis­sion be the primary crew three missions later. Cernan, Evans, and Engle served as the backup crew for Apollo 14, and as such were the primary crew for Apollo 17. Jack Schmitt was originally scheduled for Apollo 18 as the LM pilot. With the cancellation of Apollo 18, 19, and 20, there was pressure to include a scientist on Apollo 17. Thus, Schmitt replaced Engle as the LM pilot for Apollo 17. Prior to the Apollo 17 mission, Jack Schmitt’s claim to fame was cleaning up a transmission verbal faux pas of Astronaut Tom Stafford on Apollo 10 by rephrasing Stafford’s description of a crater as “bigger than Schmitt!”.

Joe Engle would never fly to the Moon, but he did fly as commander on Space Shuttle STS-2 with Shuttle pilot and future NASA Administrator Richard Truly, and as mission commander of STS-51-1. Engle is the only astronaut to fly both the X-15 and the Space Shuttle winged spacecraft into space, and to control and land the Space Shuttle manually.

The LM Challenger landed within 200 m from the planned landing coordinates. Three EVA’s were conducted, with the first EVA tasks including: the deployment of the ALSEP, deployment of the first set of geophones and explosive charges as part of the LSPE, and conducting a cosmic ray experiment using the Cosmic Ray Detector (CRD). During the second EVA, Astronauts Cernan and Schmitt used the LRV to collect core samples, dig trenches, and traverse from Nansen Crater, Lara Crater and various points along the way. These stops were made along the way to collect data from the Lunar Traverse Gravimeter (LTG) and the Surface Electrical Properties (SEP) experiment, and deploy additional LSPE geophones and explosive charges. The third EVA, additional sampling stops and traverse gravimeter mea­surements were made. Additional geophones and explosive charges for the LSPE were deployed, and the EVA ended with the retrieval of the neutron flux probe from the deep drill core hole. Each EVA lasted over 7 hours.

The Taurus-Littrow Valley is fairly easy to identify with a telescope. The site is at the southeastern rim of the Sea of Serenity and intersects the Sea of Tranquility.

Apollo 17

The landing site selected for Apollo 17 was in the Taurus-Littrow Valley on the southeastern rim of Sea of Serenity. Obtaining samples that would determine how this region of the Moon formed particularly interested lunar scientists in this landing site. The two primary objectives were obtaining samples of highland material that were older than the Imbrium impact and investigating the possibility of young, explosive volcanism in this region. Taurus-Littrow was one of several sites consid­ered, along with the Tycho crater, Copernicus crater, and the Tsiolkovsky crater on the far side of the Moon. The Tycho crater was considered too dangerous because of the roughness of the terrain. Copernicus crater was a low priority site. A far side mission to Tsiolkovsky crater created significant communications problems, with the necessity of placing a constellation of expensive communication relay satellites in orbit around the Moon to provide continuous communications with Mission Control and the command module. The Taurus-Littrow site was selected with the anticipa­tion of sampling ancient highland material and young volcanic material in the same landing site. The Taurus-Littrow site also provided the sampling of Tycho ejecta, and geologists suspected some of the craters in the area could be volcanic vents.

Apollo 17

As an observer increases magnification, under steady seeing, the landing area can be seen to have both lighter or darker material. The geologists referred to this mate­rial as light mantle and dark mantle material, stemming from suspected lava flows.

Apollo 17

Fig. 9.5 Zoom-in on the Apollo 17 landing site. Courtesy of the author

The chosen landing site is in an area between two geological massifs, or moun­tain masses, where observational evidence showed dark material from either land­slides or pyroclastic deposits. This dark mantle material is covered with small craters, which scientists at the time postulated either volcanic or meteoric in origin. The results of the Apollo 17 geological studies suggest that approximately 100 mil­lion years ago, lava seeped to the Moon surface and flooded and pooled to form the Taurus-Littrow area and Sea of Serenity. The lava flows apparently were accompa­nied by fire fountains, which formed both orange and dark-colored beads in the soil. Several samples of lunar soil from Taurus-Littrow contained orange glass beads, causing the samples to have an orange hue. Fire fountains also accounts for the dark glassy material collected at the Taurus-Littrow landing site.

Apollo 17

Fig. 9.6 LRO view of the Apollo 17 landing site from 50 Miles Above. Photo courtesy of NASA and Arizona State University

Figure 9.6 is one of the LRO’s clearest photos of an Apollo landing, with the Challenger’s descent stage clearly visible. Since the Moon has no weather or envi­ronmental conditions that can inflict weathering on the soil, the tracks of the lunar rover and the footprints of the astronauts can be easily seen. Unfortunately, this cannot be seen with backyard telescopes. The LRO photographs are taken at an altitude of 50 miles above the lunar surface.

Also visible in this picture is a cluster of craters. It has been determined from the Apollo 17 mission, that much of the main crater cluster was the secondary impact result of the massive Tycho impact less than 95 million years ago. Most of these secondary impact craters were the result of eject spreading out downrange from the Tycho crater. The downrange pattern formed points directed at Tycho. The lighter colored material originated from landslides caused by the secondary ejecta from Tycho hitting the Taurus-Littrow massifs.

Apollo 17 LM Challenger Descent Stage

Fig. 9.7 A closer view from the LRO of the Challenger descent stage. Photo courtesy of NASA and Arizona State University

Apollo 17
Подпись: LEAM
Подпись: Packing material
Подпись: 4— RTG -Central Station
Подпись: Geopbone 2
Apollo 17

Apollo 17Apollo 17 ALSEP LROC NAC M168000580R

Fig. 9.8 LRO view of the Apollo 17 ALSEP with amazing detail of the Apollo 17 ALSEP setup. The Lunar Surface Gravimeter (LSG) and the Lunar Seismic Profiling Experiment (LSPE) and its four associated geophones can also be seen. Photo courtesy of NASA and Arizona State University

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Fig. 9.9 CM pilot Ron Evan’s view of the Taurus-Littrow landing site. Note the massifs that are prominent surrounding the landing site. Courtesy of NASA

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Fig. 9.10 This mosaic panorama of the Taurus-Littrow valley shows the mission viewpoint of the landing site. In the distance the massifs that dominate and define the area can be seen. The Lunar Rover and Astronaut Harrison (Jack) Schmitt are also shown in this panorama. Courtesy of NASA

Apollo 17

Fig. 9.11 The LRV aka the Lunar Rover

The Apollo 17 LRV carried onboard two experiments to obtain data during the lunar traverses. One experiment, the Lunar Traverse Gravimeter (LTG) measured the value of the Moon’s gravity around the Taurus-Littrow area. The LTG, by mea­suring the minute variations of gravity, provided data to determine the shape and depth of the bedrock. At each stop, the astronauts read the LTG readings over voice communications link to Mission Control. Twenty-six measurements were success­fully taken during the first, second and third traverses. This was fortunate, since the similar Lunar Surface Gravimeter (LSG) experiment, part of the ALSEP, failed to function due to a design error.

The other experiment, known as the Surface Electrical Properties (SEP) experi­ment looked for layering in Taurus-Littrow soil by transmitting radio waves into the Moon surface, using interferometry from the radio wave returns, and identifying the layers of the lunar soil. Readings were taken at each stop, with the SEP transmitter set up each time a distance away from the LRV, and the receiver mounted on the front of the LRV receiving the reflected radio signal.

Apollo 17

Fig. 9.12 History’s First Extraterrestrial Fender Bender and Body Repair! Courtesy of NASA

An interesting and historically humorous footnote to the Apollo 17 mission was mankind’s first car accident and car repair on another world. Figure 9.12 shows the makeshift repair on the right rear fender of the lunar rover. Apparently during the first EVA, Gene Cernan brushed against the Lunar Rover, and a hammer in his spacesuit shin pocket caught the LRV’s right rear fender and knocked off half of it. As a result of the broken fender, the rover kicked up a dust plume while moving. The dark dust covered the astronauts, which absorbed the heat from the sunlight and could potentially cause overheating problems for Cernan and Schmitt. The abrasive moon dust also could cause scratching of the astronauts’ visors, and affect the operation of the various latches, hinges, and joints of the LRV. At the beginning of EVA 2, using the universal fix-all duct tape, Cernan was able to re-attach the fender piece after two tries. The taped on fender lasted for over four of the 7 hours EVA 2. However, the duct tape lost some of its stickiness because of the ubiquitous moon dust. For the rest of EVA 2, time was lost as the astronauts frequently used a moon dust brush to clean off the LRV, equipment and themselves. During the break between EVA’s, Cernan and Schmitt fashioned a makeshift fender out of four lami­nated maps and duct tape while inside the relatively cleaner LM. The tape worked better this time, and the new fender was attached by using clamps from the optical alignment telescope lamp. The makeshift fender lasted for the all of EVA 3.

Apollo 17

Fig. 9.13 A large lunar Rock during found during an LRV traverse. Courtesy of NASA

Boulders of various sizes are scattered throughout the Taurus-Littrow valley. At the ALSEP area, deployed west of the Apollo 17 landing site, the boulders aver­aged about 4 m in size and were found to be more numerous than in other areas of the valley. Figure 9.13 illustrates the large rock where one of the LSPE geophones was placed.

Apollo 17

Fig. 9.14 An LSPE explosive charge. Courtesy of NASA

The LSPE included explosive charges that were placed at distances away from the geophones, which when activated, sent shock waves through the lunar soil. A total of eight charges were deployed at distances of between 100 m and 3.5 km from the LSPE at the ALSEP site. The charges were detonated after the astronauts left the surface. The direct shock waves data from the geophones were compared with delayed waves from the detonations to determine the depth of the rock bed beneath the soil.

In light of the near-disaster of Apollo 13 due to an explosion, the safety of the LSPE explosive charges was a priority for the Apollo 17 mission. To assure safety from accidental or inadvertent detonation, the design of the explosive charges needed three safety rings pulled during deployment of the charge to enable three separate subsystems to activate simultaneously. One safety ring activated a timer

that after 90 hours allowed the explosive to be detonated. The second safety ring released the physical barrier that separated the detonator from the explosive charge. The third safety ring activated the battery that provided power to the receiver and firing circuitry for one minute. With the three rings pulled, three independent actions were needed to cause the explosion: the battery timer had to activate to allow power to the firing mechanisms, the sliding physical barrier that separated the detonator from the explosives had to slide into firing position, and a radio signal from NASA on Earth had to be sent to detonate. If the activation radio signal was not transmitted and received within the one minute time window, the device would move the sliding barrier back into the safe position. The explosives charges could not be activated until after 90 hours, well past the time for liftoff of the LM ascent module for its rendezvous with the command module.

Apollo 17

The astronauts used a number of devices to take lunar surface samples. Figure 9.15 photo shows Jack Schmitt taking a drive tube sample. These 18-in. drive tubes were either pushed into or driven into the lunar surface to collect a short core sample. Two or three drive tubes could be joined together to create a longer, depth core sample. The depth of the core sample was often determined by the den­sity of the soil. Softer soil enabled the astronauts to physically sample greater depths, while hard dense soils limited the sample size.

The gnomon device was used to provide a physical scale and to color calibrate photos of lunar terrain and samples. One of the difficulties encountered during the Apollo missions was the underestimation of size and distances by the astronauts. The gnomon device provided a reference for determining physical scale. At one point, from his voice transcription at 140:58:51 and his journal notes of the Second EVA second traverse to Geology Station 2, Jack Schmitt used his own shadow as a ruler. His mission notes acknowledges that “everyone underestimates distance on the Moon”. He would call to mission control to check his shadow length from the television image uplinked from the LRV camera to give an estimate of scale. Even mission commander Cernan admitted misjudging distance on the Moon.

Apollo 17

One of the discoveries made during Apollo 17 was uncovering orange soil dur­ing EVA 2. None of the previous Apollo missions ever uncovered this orange-hue soil. The orange soil was first identified by Jack Schmitt on the fourth stop of the second traverse. It pays to have a scientist on the mission!

Apollo 17

A magnified view of the spheres and fragments in the “orange” soil which was brought back from the Taurus-Littrow landing site by the Apollo 17 crewmen may be seen In Fig. 9.17. Scientist-astronaut Harrison H. “Jack” Schmitt discovered the “orange” soil at Shorty Crater during the second Apollo 17 lunar surface extrave­hicular activity (EVA). The orange and dark glass beads provided clear evidence of volcanic fire fountains to geologists.

Apollo 17

Fig. 9.18 The Lunar Neutron Probe Experiment. Courtesy of NASA

At the end of the third and final traverse, the 2-m long probe for the Lunar Neutron Probe Experiment (LNPE) was retrieved and deactivated at the end of the third EVA after 49 hours of exposure. The LNPE was designed to obtain data on neutron capture rates in the lunar regolith as a function of depth. The LNPE was an outgrowth from the analyses conducted of lunar samples returned from the Apollo 11 mission. In an effort by scientists to understand the processes that created the lunar soil, early studies indicated that neutron capture of certain isotopes of samar­ium and gadolinium were involved. The experiment was to gather data that would enable scientists to estimate the age of the lunar soil. The LNPE was deployed northwest of the lunar module in the hole from the deep drill core. Figure 9.18 shows the gold-colored Mylar transport bag and the treadle used for recovering the deep drill core.

The last view of the LM Challenger descent stage taken by the Apollo 17 remote video camera is shown in Fig. 9.19. A little known fact about the televised liftoff of Challenger from the Moon’s surface is that the television camera was manually controlled from Mission Control. The NASA controller manually panned the remote controlled camera 2 seconds ahead of the LM launch to compensate for the delay time of the transmission to the Moon. Millions of television viewers on Earth were treated to a live broadcast of the LM liftoff because of this carefully planned and executed action.

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Fig. 9.19 Challenger’s liftoff from the Moon. Courtesy of NASA

The television broadcasted launch of the LM Challenger culminated the evolu­tion of Apollo television cameras. The lunar-surface images provided by the cam­eras used on Apollo 15, 16, and 17 were of much higher quality than those used in the earlier Apollo missions. The Apollo television camera used on Apollo 11 was of poor quality, producing blobby low resolution black-and white images. The color cameras used during the Apollo 12 and 14 missions were too light sensitive, with the Apollo 12 astronauts burning out the video tube by pointing it at a reflected surface of the LM. Apollo 14 television images showed Astronauts Alan Shepard and Edgar Mitchell as white blobs most of the time. By the J-missions, a high quality color camera had been designed, implemented, and space and lunar qualified for use.

After the LM Challenger ascent stage rendezvoused with the CM America, the Challenger ascent stage was sent crashing into the Moon, with the ALSEP geo­phones left behind by Apollo 12, 14, 15, 16, and 17 recording the impact. NASA reported the ascent stage impacted the Moon at coordinates 19.96 N, 30.50E at 1:50 EST on 15 Dec 1972.

The spent Saturn IVB third stage for Apollo 17 impacted the lunar surface at 4.21S latitude, 12.31 W longitude at 3:32:42 pm EST on 10 Dec 1972.

As of this writing, Apollo 17 has proved to be the last time man has set foot on the Moon.

Excerpt from his speech delivered before a joint session of Congress May 25, 1961

First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so dif­ficult or expensive to accomplish. We propose to accelerate the development of the appropriate lunar spacecraft. We propose to develop alternate liquid and solid fuel boosters, much larger than any now being developed, until certain which is supe­rior. We propose additional funds for other engine development and for unmanned explorations—explorations which are particularly important for one purpose which this nation will never overlook: the survival of the man who first makes this daring flight. But in a very real sense, it will not be one man going to the Moon—if we make this judgment affirmatively, it will be an entire nation. For all of us must work to put him there.

Second, an additional 23 million dollars, together with 7 million dollars already available, will accelerate development of the Rover nuclear rocket. This gives promise of some day providing a means for even more exciting and ambitious exploration of space, perhaps beyond the moon, perhaps to the very end of the solar system itself.

Third, an additional 50 million dollars will make the most of our present leadership, by accelerating the use of space satellites for worldwide communications.

Fourth, an additional 75 million dollars—of which 53 million dollars is for the Weather Bureau—will help give us at the earliest possible time a satellite system for worldwide weather observation.

Let it be clear—and this is a judgment which the Members of the Congress must finally make—let it be clear that I am asking the Congress and the country to accept a firm commitment to a new course of action, a course which will last for many years and carry very heavy costs: 531 million dollars in fiscal’62—an estimated 7 to 9 billion dollars additional over the next 5 years. If we are to go only half way, or reduce our sights in the face of difficulty, in my judgment it would be better not to go at all.

Now this is a choice which this country must make, and I am confident that under the leadership of the Space Committees of the Congress, and the Appropriating Committees, that you will consider the matter carefully.

It is a most important decision that we make as a nation. But all of you have lived through the last 4 years and have seen the significance of space and the adventures in space, and no one can predict with certainty what the ultimate meaning will be of mastery of space.

I believe we should go to the Moon. But I think every citizen of this country as well as the Members of the Congress should consider the matter carefully in mak­ing their judgment, to which we have given attention over many weeks and months, because it is a heavy burden, and there is no sense in agreeing or desiring that the United States take an affirmative position in outer space, unless we are prepared to do the work and bear the burdens to make it successful. If we are not, we should decide today and this year.

This decision demands a major national commitment of scientific and technical manpower, materiel and facilities, and the possibility of their diversion from other important activities where they are already thinly spread. It means a degree of dedi­cation, organization, and discipline which have not always characterized our research and development efforts. It means we cannot afford undue work stop­pages, inflated costs of material or talent, wasteful interagency rivalries, or a high turnover of key personnel.

New objectives and new money cannot solve these problems. They could in fact aggravate them further—unless every scientist, every engineer, every serviceman, every technician, contractor, and civil servant gives his personal pledge that this nation will move forward, with the full speed of freedom, in the exciting adventure of space.

Moon, Mars,. and the Future

On September 12, 1962, President John F. Kennedy spoke at Rice University and spoke these immortal words that launched the United States on its quest to the Moon:

We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.

In an era of international and geo-political competition, President Kennedy launched the United States into its decade long quest that culminated in the Apollo landings that are the subject of this book.

Now over 40 years after those historic manned Apollo landings, a number of other countries including Japan and China, are taking aim at our satellite neighbor. During the writing of this book, China soft landed a robotic rover onto the Moon.

Meanwhile, the United States and NASA, with a number of fits and false starts, inches its way towards a manned mission to the other legendary celestial objective, Mars. Robotic Mars rovers such as Curiosity, Opportunity, and Spirit have landed and explored Mars, and have expanded our knowledge of our red planet neighbor.

The Moon and the planet Mars dominate the imaginations of mankind. Literature of all cultures, both poetry and prose, are filled with the romance, the science, and the adventure of traveling to the Moon and Mars. Well-known authors, such as H. G. Wells, Edgar Rice Burroughs, Ray Bradbury, and Isaac Asimov, have penned books about the Moon and Mars.

To each generation, the Moon and Mars represents a challenge, impacting its technology, medical sciences, society, and culture.

A look at the challenges that the Apollo program faced, and the comparison that a Mars effort will have to overcome, is in order.

The Refractors

Ask someone to close their eyes and picture in their mind a telescope. Or better yet, ask a child to take a crayon and draw on a piece of paper a picture of a telescope. More likely than not, the image of a long tube pointed at the skies with an observer peering through the opposite end is the result. The refractor is the intuitive concept of a telescope.

Historically, the refractor is the earliest design for telescopes, with the earliest examples appearing in the Netherlands in 1608. Spectacle makers Hans Lippershey and Zacharias Janssen are two of the early creators of the design. Within a year or two Galileo created his own improved refractor design, pointed his telescope into the night sky, and history was made.

Conceptually, a refractor is a system of lenses with an objective lens system to gather light and an eye lens system to focus the light gathered by the objective lens into an image for the observer. Hence, the intuitive mental picture of a long tube with an objective lens pointed at the sky and an observer viewing through the oppo­site end focusing the eyepiece.

Inch-for-inch, refractors are regarded by the astronomy community as the best performing telescopes. Sharp, pin-point star images, and high contrast planetary images are their hallmark. Four inch or larger diameter refractors are the primary instruments of lunar and planetary observers. Astrophotographers have adopted apochromatic refractors as their go-to telescopes, producing the sharp and contrasty images that rival professional observatories.

In today’s world of refractor telescopes, there are achromats and apochromats, terms created to differentiate the levels of color correction of the respective lens systems. Grade school science demonstrates that sunlight passing through a prism separates sunlight into its constituent colors. In optical systems, such as telescopes, all types of optical glasses exhibit some degree of separation and dispersion of light into primary and secondary colors.

The Refractors

A classic achromatic refractor uses a two lens objective, with one lens made of crown glass, and the other lens made of flint glass. With the lenses ground with proper curves and using glasses with different refractive indices, the result is a telescope that can bring to focus two of the three prime colors of light, typically red and blue wavelengths. So conceptually, the achromat can produce an improved image of a distant object over a single lens objective of the type used by Galileo. In practice, there are some color errors, or chromatic aberrations, that creep into the visual performance of an achromatic refractor, especially at shorter focal lengths. The primary colors do not focus at the same point, resulting in a color fringe around Moon, planets or bright stars. This chromatic aberration also results in diminished sharpness and definition in the telescope image. Many classic early refractors typi­cally have focal ratios of f/11, f/15, or f/20 or greater to minimize chromatic aber­rations and become “color-free”. Even at long focal lengths, achromats can display chromatic aberrations, where the secondary colors of yellow and purple wave­lengths do not come to focus.

This technical discussion gives the impression that achromats are flawed. That couldn’t be farther from the truth. Today’s achromatic designs use different types and combinations of Extra-low Dispersion, or ED, glass to lower the chromatic aberrations to a minimum. Modern designs of achromats have minimized the false color to a high degree. One current builder of high quality refractors has taken advantage of new glass technology and our light polluted skies. With a combination of ED glasses, altered lens curves, and adjusting the air spacing between the two lenses of the doublet, the color error in the violet wavelengths match the not-quite – black-really-deep-purple light polluted background sky, resulting in an excellent performing telescope that produces sharp and crisp images with the color error conveniently and cleverly hidden in the background. There are specialized long focus 102 mm achromatic refractors on the market with f/11 focal ratios or greater specifically designed for viewing the Moon and the planets. These modern “planet killers” take advantage of low dispersion glasses and long focal length to provide images that rival apochromatic refractors at one third the cost.

The Refractors

Sometime in the 1980s, the apochromatic refractor became commercially available to the amateur astronomy market. Sophisticated designs appeared using combinations of two, three, or four lenses of exotic glasses. Advanced telescope owners found themselves developing and reveling in a new vocabulary that included terms such as fluoro-crown, lanthanum, fluorite, FPL-51 or -53, APO – triplet, and Petzval. These apochromats offered improved sharpness, contrast, and color correction over the classic achromat refractors, while at the same time creat­ing a more portable telescope with f-ratios of f/8 or less. But this optical perfor­mance improvement is costly. Apochromats are typically 2-10 times more expensive that an equivalent aperture achromatic refractor. Apochromats get expen­sive very quickly as the size increases. A typical 80 mm apochromat retails in the $700 range. A 102 mm triplet can easily cost over $2,500. 130 mm apochromats range fall into the $4,000-$5,000 realm, and you can buy a car with the money needed for larger apochromats.

The old telescope salesman explanation of an achromat refractor is a “color-free image”, meaning no color fringing in the telescopic image. The telescope salesman pitch for an apochromat is “this time, I’m serious! It’s color-free!”. Depending on the sensitivity and sensibility of the observer, the image improvement of an apo – chromat over an achromat can be either a slight or a day-night difference. A lot depends on the sensitivity and sensibility of the refractor owner. From a technical viewpoint, there is no question that the apochromatic refractor offers the best tele­scopic images over an achromatic refractor. In fact, as discussed later in this chap­ter, an argument can be made that an apochromat is inch-for-inch better than every other telescope design, whether refracting, reflecting, or catadioptric.

The Refractors

Countless astronomy books and websites over the years have presented valid arguments that the Newtonian reflector represents the most “bang for the buck” in telescopes. Originally designed by Sir Isaac Newton in 1668, this telescope represents a simple design using either a spherical or parabolic main mirror to collect light and a flat diagonal mirror to reflect the collected light to the eyepiece and the observer. By limiting the number of optical surfaces that need to be accu­rately figured and polished to two, the cost for a Newtonian telescope can be minimized. In contrast, a doublet refractor needs four optical surfaces, and a triplet apochromat needs six optical surfaces to be accurately ground, figured, and polished. The Newtonian design, being reflective in nature, has no chromatic aberrations and can be constructed from less expensive materials. During the explosive growth of Newtonian telescopes in the 1980s, with John Dobson’s unique implementation of the design, Newtonians could be made from Pyrex glass, cardboard tubes, and plywood.

Sounds like the perfect telescope. An 8 in. Newtonian reflector on a Dobsonian mount can be easily acquired for the price of a 3-in. achromat refractor. That is a lot of performance for the money.

But there is a catch. Ask any telescope dealer, any telescope salesman, or any member of your local astronomy club, “What is the most common telescope problem?” Nine times out of ten, owners of Newtonian telescopes are unable to align the optics of their telescopes. The main mirror is tilted, the diagonal is not centered, the tilt of the diagonal needs adjustment, or a combination of all three leads to frustration for the telescope owner, resulting in a telescope that ends up in the closet. Whereas refractors and some catadioptric designs do not need col – limation alignment under normal use, Newtonian telescopes require frequent maintenance. This alignment skill is easily acquired by some, while others find the alignment task difficult. Some telescope owners take collimation in stride, while others find it a nuisance.

The Refractors

The Refractors

Fig. 2.6 The Maksutov-Cassegrain Telescope. Courtesy of Adam Chen

Catadioptric telescopes are a category of telescopes that combine lens and mir­ror technology to produce compact and transportable instruments. With a clever combination of a lens and mirrors, the incoming light path is folded upon itself, and any optical aberrations of the reflecting surfaces can be corrected by the refracting lens.

Catadioptrics are available in two popular forms: Schmidt-Cassegrain tele­scopes, or SCT and the Maksutov-Cassegrain telescope. Maksutov-Cassegrains appeared on the commercial market in the mid-1950s, and SCT’s burst into popu­larity in the 1970s. As a family, catadioptrics offer a high degree of optical perfor­mance and low maintenance in a small compact package.

Although SCTs are available in sizes from 5-in. to massive 14 and 16 in. aper­tures, the most popular and best-selling telescope since the 1970s has been the 8-in. SCT. The 8-in. SCT is the basic core product for not one, but two major telescope companies. The reason for this popularity stems from the all-around versatility that the design provides. As an analogy, the 8-in. SCT is the Olympic Decathlon Champion of telescopes. The Olympic Decathlon gold medalist doesn’t excel in any singular competition, such as the 100 m dash or the high jump, but is able to per­form 10 different events better than anyone else can perform those same events. Versatility and a high level of performance are outstanding attributes of an 8-in. SCT. The 8-in. aperture allows for light gathering for deep sky objects, the typical f/10 focal length enables high magnification for lunar and planetary observations, numerous attachments are available for photographic use, and the compact size ensures frequent usage. But it’s not perfect for any singular use. Newtonian tele­scopes are available at a cheaper price in larger sizes for deep sky light gathering. Refractors produce images that are of better quality in contrast and sharpness. Many amateur astronomers tend to own two, three, or more telescopes in order to optimize their viewing. But if a person is only going to own one single telescope that is capable of handling multiple astronomy tasks, the 8-in. SCT is the likely choice.

Maksutov-Cassegrain, or Maks for short, are highly popular smaller telescopes in the 3.5-6 in. diameter range. Costing from $400 to an astronomical (pardon the pun!) $4,000, these little gems of the telescope world are available in every configu­ration conceivable. Maks tend to have long focal lengths in the f/12 to f/15 range, which helps to improve contrast but limits the field of view. Available on simple manual mounts, to equatorial mountings, to high tech computerized go-to systems, Maks are as versatile as their SCT counterparts. Due to the compact size, Maks make excellent travel scopes.

The natural question that arises from all these discussions of telescope design is: What telescope is ideal? Recalling the car analogy, it depends on the type of observing.

For observing the Moon and planets, the answer is clear. Refractors offer the sharpest, clearest, and most contrasty images. But why? A discussion is needed on the difference between unobstructed and obstructed optics. As seen in Figs. 2.4, 2.5, and 2.6, the Newtonian and the catadioptric designs share a common attribute of a secondary mirror that is centrally located along the light path. These secondary mir­rors allow for the folding of the light path to direct the incoming light to the eyepiece. In the case of the Newtonian, the secondary diagonal serves to guide the light to the side of the telescope to the focuser. In both catadioptric designs, the secondary mirror fold the light path creating a very compact telescope that enables portability. The commercially available Newtonians have secondary mirrors that measure approxi­mately 30-35 % the diameter of the primary mirror. Most SCTs and Maks the central obstruction of the secondary mirror constitutes 40 % the diameter of the primary mirror. The main impact of the central obstruction is a decrease in sharpness and contrast in the telescope image. What is the difference in performance between the unobstructed refractor and an obstructed design? The best analogy is to compare the familiar standard definition TV versus HDTV. A good SCT or short-focus Newtonian will offer a good lunar image like that of a standard 480i digital TV image, but a good ED achromat or apochromatic refractor is like watching a 1080p high-definition TV.

Any of these telescope designs can be used to view the Moon. If the reader of this book currently owns a telescope, proceed to the following chapters and find the Apollo landing sites and enjoy. To those looking to purchase a telescope, the fol­lowing recommendations are offered based on telescope technology, decades of amateur astronomy field experiences, and telescope retail experience:

• For lunar and planetary observing, an 80 mm-to-102 mm refractor is the top choice. These refractors are light, portable, and low maintenance telescopes that offer sharp contrasty images of the Moon and planets. Remember, the reason that large telescopes exist is to act as light buckets and gather the faint distant light of stars, galaxies, and nebulas. The Moon is bright. Really bright. Light gathering is the least of your problems in lunar observing. And when aperture fever occurs, and a larger bulkier telescope is acquired, the refractor takes the role of the easy-to-use, grab-and-go scope. No wasted money here.

• As discussed earlier, it’s hard to argue against an 8-in. SCT. Yes, the lunar images are a little soft compared to a 102 mm apo refractor, but the overall versatility cannot be denied.

• A long focus f/10 or greater Newtonian has a central obstruction approximately 25 % of the primary diameter, and comes very close to refractor image quality. These telescopes are difficult to find in the commercial market, but there are some of these gems on the used market.

• 90-125 mm Maksutov-Cassegrains should also be considered, especially when small size is a requirement.

The Eyepieces

The Refractors

Fig. 2.7 The Author’s Collection of Telescope Eyepieces. Courtesy of the author

Telescope design is only half of the optical story. The rest of the story are the eye­pieces at the focus end of the telescope. And here again, there’s another zoo filled with strange and wonderful denizens that are vying to complete the optical train. Kellner, Abbe, Konig, Brandon, and Nagler are all names of optical designers who have lent their names to their eyepiece designs, and are now an accepted part of the astronomy vocabulary. There are 0.965, 1.25, and 2 in. eyepieces. Some designs have been around for over a century, and some designs are less than a decade old. And most have valid use in astronomy.

The Refractors

Fig. 2.8 (a) Huygens. Courtesy of the author. (b) Ramsden. Courtesy of Adam Chen

Two of the oldest and simplest of the compound eyepiece designs are the Ramsden and Huygens. Originating from the 1700s, these eyepieces serve as historic curiosities. Occasionally, an antique Ramsden will show up at swap meets, eBay, or even antique stores. The Huygens eyepieces are still supplied in 0.965 in. size on cheap beginner telescopes sold at department stores and big-box stores. Both designs are flawed, with narrow apparent fields, chromatic aberration, and short eye relief.

The Refractors

Fig. 2.9 Kellner design. Courtesy of Adam Chen

In the mid-1800s, the Kellner eyepiece was developed by replacing the singlet eye lens element of a Ramsden with a achromat doublet. This resulted in a better performing design with a wider field, better color correction, and less spherical aberrations. When used on long focus telescopes, Kellners still produce a reason­ably good image. The main shortcoming of the Kellner is ghosting when looking at bright objects. So Moon watchers beware! The design exists today under various names, including Modified Achromat, RKE, and modified Kellner. These eyepieces are a good economical alternative for those on a budget.

The Refractors

Fig. 2.10 orthoscopic. Courtesy of Adam Chen

The Refractors

Fig. 2.11 The Plossl orthoscopic. Courtesy of Adam Chen

The Refractors

Fig. 2.12 The Konig orthoscopic. Courtesy of Adam Chen

An examination of the patents for the Abbe, Plossl, and Konig eyepiece designs describes all three as orthoscopic designs. The term “orthoscopic” means free from distortion. In common astronomy vernacular, the term orthoscopic has evolved to become synonymous in name with the Abbe design.

The Abbe has stood the test of time. Since the 1950s, through the growth of amateur astronomy in the 1960s and 1970s, the Abbe design has been highly regarded for sharp and high contrast images. The classic “volcano top” Abbe ortho – scopic, so named for its distinctive beveled shape, are well-known and are highly desired. These Abbe eyepieces have been made by an optician from Japan named Tani-san, whose retirement in 2013 brought an end to decades of Circle T volcano top eyepieces. But don’t fret, Abbe orthoscopic eyepieces are available through other sources. The Abbe orthoscopic eyepiece was held up as the pinnacle of eye­pieces until the advent of new revolutionary wide-angle and high eye relief eye­pieces in the 1980s. Today, dedicated lunar and planetary observers still insist on Abbe eyepieces today.

The Plossl eyepiece has a interesting reputation in the amateur astronomy world. In the 1960s, the Plossl only existed as a rare and mysterious eyepiece, commer­cially available from a small vendor in Europe. Then in the 1980s, Plossls suddenly became widely available, to the point now where it is so commonplace that the eyepiece is considered mediocre by average backyard astronomer. Nothing could be further from the truth. Although poorly manufactured examples exist, a premium Plossl is an extraordinary eyepiece, versatile in lunar, planetary, and deep sky use. There exists a number of variants of the design in which an extra lens or two to the system, somewhat blurring the definition of a Plossl, but these variants tend to be of high quality and offer high performance.

Not as widely available as the other orthoscopics, the Konig design has its fans. Depending on the implementation, the Konig potentially offers a wider field-of – view than the Abbe or Plossl. In practice, the Konig achieves a wider field, but with a slight sacrifice of edge of field sharpness, and slightly shorter eye relief.

A variant of the Konig design is the Brandon eyepiece. Chester Brandon devel­oped his eyepiece design during his time at the Frankford Arsenal in Philadelphia. The eyepiece design was widely used during World War II in U. S. Army optics. The Brandon design differs from the Konig by using three high index glass types and four different lens radii. When marketed in the 1950s as a high priced premium eyepiece, the Brandons were priced at $15.95. My how times have changed, with the price of Brandons and many premium eyepieces in the three-digit range. With sharp crisp contrasty images, the Brandon reputation exceeded that of any other 1950s eyepiece, and is still the go-to eyepiece for many lunar and planetary observers today.

The Refractors

Fig. 2.13 (a) The Erfle. Courtesy of the author. (b) Modern Wide-Angle. Courtesy of Adam Chen

During World War II, a number of scopes used for spotting or for aiming weap­onry by the American armed forces were equipped with Erfle eyepieces. In the 1950s and 1960s, war surplus Erfle eyepieces became available for amateur astron­omers seeking wide-angle views through their telescopes. With an apparent field of view of approximately 60°, these large eyepieces created a demand for wide field eyepieces. That wide-angle demand has grown over the years, to the point now where the consumer demand for ever wider fields of view drives the eyepiece industry. The Erfle does not display as sharp an image in the center of the field as the orthoscopic eyepiece, and a degradation of the image occurs in the outer third of field. Newer modern wide-field designs use exotic glass types and different lens configuration and curves to correct the edge degradation, while at the same time providing a wider field of view.

The Refractors

Fig. 2.14 The Nagler and related ultra wide angle eyepieces. Courtesy of Adam Chen

The quest for an ever wider field-of-view exploded with the introduction of the Nagler eyepiece. Competitors quickly followed, with virtually every telescope company offering their version of an over 80° field-of-view eyepiece. The ante was raised again with the introduction 100° and even wider field-of-view eyepieces in recent years. These eyepieces contain seven or more lenses in their complex designs in an effort to provide wide fields without sacrificing sharpness at the edge of the field. These eyepieces are not cheap, with many exceeding the cost of many telescopes! These eyepieces are outstanding for deep sky and wide field applica­tions. However the complex design, high number of optical surfaces, plus the inevi­table, although slight, light absorption caused by the amount of glass in the light path, these ultra wide angle eyepieces do not offer the same level of sharpness and contrast as the simpler orthoscopic designs.

The Refractors

Fig. 2.15 The Barlow lens. Courtesy of Adam Chen

While not an eyepiece, a Barlow lens is a useful addition to every eyepiece case. A Barlow lens is a negative lens system placed along the light path between the objective and the eyepiece that increases the effective focal length of the telescope, therefore increasing the magnification. Typically, Barlows double (2x) or triple (3x) the magnification. Newer focal extenders using three or four lens elements are available to quadruple (4x) or quintuple (5x) the focal length. These accessories are useful in three ways. A single Barlow lens effectively doubles the number of mag­nifications available in an eyepiece collection. The use of a focal extender also allows longer focal length eyepieces with their higher eye relief to be used at higher magnifications for eyeglass wearers. The use of a Barlow lens can improve the off – axis edge sharpness of some eyepiece designs. The Barlow lens and related focal extenders are also useful for astrophotography.

Some discussion is needed on the subject of zoom eyepieces. In the 1960s, the zoom eyepiece earned a reputation for mediocre optics and was not worth the money. Today’s zoom eyepieces deserve some attention. Improvements in lens coat­ings, the introduction of high index glass, and improved manufacturing has yielded a modern zoom that is worthy of a spot in an observer’s eyepiece case. Although still narrower in field-of-view at longer focal lengths, and wider at shorter focal lengths, the performance has been greatly improved. A zoom eyepiece will not take the place of an eyepiece collection for critical observing, but serves the role for quick look situations, or when showing the night sky to children whose short attention spans don’t allow for the changing and refocusing of conventional eyepieces to change magnification. Viewing the Moon through a 102 ED refractor with an 8-24 mm zoom eyepiece served as an inspiration for the title and subject of this book.

The driving criteria for eyepiece selection for lunar and planetary observing is sharpness and contrast. The rule of thumb for selecting the right eyepieces for view­ing the Moon is “the simpler the better”. The classic Abbe, Plossl and Brandon designs are the preferred choices. There are more esoteric lunar and planetary eyepiece designs based on the monocentric design, or on proprietary designs. These are not discussed here due to their low availability.

There is an Achilles heel to the three classic orthoscopic designs. The older eyepiece designs perform best in longer focal length telescopes. In the era in which these designs originated, telescopes had long focal lengths, typically f/10 or greater. At f/20, even the lowly Ramsden design performs well. But many of today’s tele­scopes have much shorter focal lengths, often f/6 or shorter. The classic designs suffer from loss of edge sharpness because of the steeper angle of the light cone from the objective as it enters the eyepiece. Modern designs take into account the shorter focal length telescopes of today. The design rationale for many of the updated configurations of the Plossl design has been to widen the field-of-view and improve performance with short focal length telescopes.

The recommendation for the ideal eyepiece for lunar observing is as follows:

• For telescopes with a focal length of f/7 or greater, the Abbe or Plossl designs will perform at the highest level.

• For telescopes with focal lengths of less than f/6, the modern variants of the Plossl are suggested.

• For observers who must wear glasses while viewing, there are some proprietary eyepiece designs that provide 20 mm of eye relief. These tend to be premium eyepieces that use exotic lens configurations and glasses, and therefore are not cheap. But they are recommended for eyeglass wearers.

• Consider using a Barlow in combination with a low – or medium-power eyepiece in order to obtain higher magnifications. The comfortable eye relief from this combination is often preferred by both eyeglass wearers and non-eyeglass wear­ers. The classic orthoscopic high power (4 mm and 6 mm) eyepieces are notori­ous for their near-pinhole sized eye lens.

Binoculars and Telescopes

Dickinson, Terence and Alan Dyer, The Backyard Astronomer’s Guide, 3rd Ed., Firefly Books LTD., 2008.

This is a comprehensive book that is a must have for any amateur astronomer, beginner or advanced. It provides coverage of telescope and binoculars, astronomical viewing, and astro-photography.

Dickinson, Terence, Nightwatch, 4th ed., Firefly Books, 2006.

One of the most recommended beginner’s guides to the hobby of astronomy. If one has never owned a telescope before, this is an excellent place to start.

Harrington, Philip S., Star Ware – The Amateur Astronomer’s Guide to Choosing, Buying, and Using Telescopes and Accessories, 4th ed., John Wiley and Son, Inc., 2007.

As the subtitle states, this book is highly recommended to help the sort through the maze of equipment available for anyone in the market for astronomy equip­ment. This book provides a consumer’s guide of most of the brand name astronomy equipment available in the marketplace.

Consolmagno, Guy and Dan M Davis, Turn Left at Orion, Cambridge University Press, 1989.

An excellent observer’s book highlighting a hundred night sky objects that can be seen through modest sized telescopes. A section of the book is devoted to the Moon, with galaxies, nebulae, and star clusters comprising the rest of the book. The beauty of this book is its presentation of each objects view as seen naked eye, though a finder scope, and then through the eyepiece of a telescope. Highly recommended.

The Ranger Series

The Ranger Series

Fig. 10.1 The Ranger. Courtesy of NASA

The Ranger Program was NASA’s first step in achieving President Kennedy’s goal of landing a man on the Moon and returning him safely by the end of the 1960s. This long forgotten lunar probe program was initially a source of embarrassment to NASA and the nation, but eventually achieved its goals and paved the way for the Surveyor Program, followed then by the Apollo triumphs. The Ranger spacecraft mission evolved into a simple task: to take images of the lunar surface and return those images to Earth by a telemetry link until the Ranger spacecraft smashed into the Moon.

The Ranger Series

The Ranger Series

Fig. 10.3 LRO photo of the Ranger impact sites. Photo courtesy of NASA and Arizona State University

In the scope of this book, consider visually locating the Ranger sites with a telescope as extra credit. LRO photos have located the Ranger impact sites with difficulty. Fortunately, the Apollo 12 landing site is not only within walking dis­tance of Surveyor 3, but is also within the general area of the Ranger 7 impact zone. Apollo 11 also landed in the general vicinity of Ranger 8. To the backyard observer, basically locating Apollo 11 and Apollo 12 also encompasses the Ranger 7 and Ranger 8 impact zones. To locate the Ranger 9 impact site, first locate the major crater Ptolemy. The crater just south of Ptolemy is the crater Alphonsus, and Ranger 9 impacted just slightly north and east of the central peak within the crater.

The Ranger program was a series of unmanned lunar missions by NASA in the early 1960s whose design goal was to obtain the first close-up images of the lunar surface. The development of the basic Ranger spacecraft system began in 1959. The original concept for Ranger included a gamma ray spectrometer, radar altimeter, television imaging system, and a soft landing seismometer. These scientific equipment should sound familiar as parts of the eventual Apollo sci­entific equipment suites. The first six Ranger missions were complete failures, as NASA went through a learning process for developing space capable vehi­cles, space navigation, and launch technology and procedures. Ranger 1 and 2 were launch failures, and Ranger 3 and 5 totally missed the Moon. Ranger 4 impacted the Moon but experienced electronic systems failure. Ranger 6 impacted the Moon, but its cameras failed to function. At one point, the program was called "shoot and hope". After two congressionally mandated reorganiza­tions of NASA and JPL, the Ranger program was stripped of much of its scien­tific equipment and simplified to its final kamikaze space camera configuration. Ranger 7 successfully returned images in July 1964, followed by two more successful missions.

The Ranger spacecraft had three different configurations.

• Block I, consisting of Ranger 1 and 2, were test missions. They were launched in 1961 for engineering development, and were not targeted for the Moon. The Ranger 1 spacecraft was designed to go into an Earth parking orbit and then into an extended elliptical Earth orbit to test systems and strategies for future lunar missions. Ranger 1 was launched into the Earth parking orbit as planned, but the Agena B booster stage failed to restart to put it into the higher trajectory, so when Ranger 1 separated from the Agena stage it went into a low Earth orbit and began tumbling. The satellite re-entered Earth’s atmosphere on August 30, 1961. The Ranger 2 followed a similar fate, and was launched into a low earth parking orbit, but an inoperative roll gyro prevented the Agena booster stage restart. As with its predecessor, Ranger 2 could not be put into its planned deep-space tra­jectory, and was stranded in low earth orbit upon separation from the Agena stage. The orbit decayed and the spacecraft reentered Earth’s atmosphere on November 20, 1961.

• Block II missions comprising of Ranger 3, 4, and 5, were launched during 1962 to achieve rough lunar landings, obtain science data, and test approach television camera operations. These Ranger spacecraft experienced satisfactory vehicle performance, but Ranger 3 missed the Moon by approximately 23,000 miles and Ranger 5 missed the Moon by about 450 miles. Ranger 4 suffered electronics problems that caused the solar panels to not open. Ranger 4 battery power failed after 10 hours and the probe was unable to perform mid-course corrections or activate its cameras. Ranger 4 impacted the Moon on the far side.

• Block III Missions were the Ranger 6, 7, 8, and 9 which used the experience of the earlier Ranger missions to achieve success in 1964 and 1965. NASA learned its lessons on navigating to the Moon and made technology modifications to enable transmission of high-resolution photographs of the lunar surface during the final minutes of flight. Ranger 6 performed satisfactorily en route to the Moon, but the camera failed to operate before lunar impact. Success finally came with Ranger 7, 8, and 9, as those missions fulfilled NASA objectives and provided more than 17,000 photographs at resolutions higher than ever achieved. The Ranger 7 and 8 missions provided coverage of the two types of mare terrain that included the area of the eventual Apollo 11 landing site. Ranger 9 provided coverage of the highland region, impacting in the large central highland crater Alphonsus.

The Ranger photographs provided valuable photographic information for future landing site selection for Surveyor and Apollo missions, and provided surface detail unavailable from Earth-based observations. Each Ranger space­craft had 6 cameras on board. The basic cameras were the same with each camera set up for different exposure times, fields of view, lenses, and scan rates. The camera system was divided into two channels, P for partial and F for full, with each channel design having with independent power supplies, timers, and transmitters.

• The F-channel had 2 cameras: the wide-angle A-camera and the narrow angle B-camera. The final F-channel image was taken between 2.5 and 5 seconds before impact at an altitude of approximately 10,000 feet.

• The P-channel had four cameras: P1 and P2 (narrow angle) and P3 and P4 (wide angle). The last P-channel image was taken between 0.2 and 0.4 second before impact at an altitude of approximately 2,000 feet.

The images provided better resolution than was available from Earth based views by a factor of 1000. The smallest crater that earthbound telescopes could achieve was about the size of a large NFL or major college football stadium, while the images produced by the Ranger cameras showed from pickup truck sized cra­ters down to the 1 feet sized features in Ranger 9 photos. These high resolution images showed Apollo mission planners that finding a smooth landing site was not going to be easy.

The Ranger Series

Fig. 10.4 Photo Sequence taken by Ranger 7 a camera approaching the Moon. Courtesy ofNASA

The Ranger Series

Fig. 10.5 Courtesy of NASA

The Ranger Series

The Ranger Series

The Ranger Series

Fig. 10.8 Photo Sequence taken by Ranger 7 p camera approaching the Moon. Courtesy ofNASA

The Ranger Series

Fig. 10.9 Courtesy of NASA



Courtesy of NASA

Sunday, July 20, 1969. 4:10 pm EDT.

For readers of a certain age, this is a date and time that can never be forgotten. A moment in time in which everyone remembers where they were, and what they were doing. And unlike other dates that live in infamy, such as December 7 or 9/11,
this is a moment of history that brings awe, inspiration, and pride. For this was the day that Neil Armstrong and Buzz Aldrin landed the LM Eagle on the Moon.

Decades later, generations of people look to the Moon, and know that mankind has been there. But many have no idea where the landings occurred. The Moon has been visited by both robotic and human visitors, with landing sites scattered across its surface. It is the goal of this book to enlighten the reader, and show where to look upon the Moon for mankind’s landing sites.

As a child of the Sixties, I grew up entranced by the burgeoning Space Age. I received as a Christmas present my first telescope at the age of eleven, and my first target was to view the Moon. It was thrilling. I grew up to become a professional engineer, spending most of my career in the field of aviation. But my love for tele­scopes and astronomy never waned. Since my retirement, I have devoted a great deal of time supporting local Washington D. C. telescope stores and giving lectures on telescopes and astronomy equipment to astronomy clubs in Maryland and northern Virginia. And for those of sharp memories and a stack of old astronomy magazines in their basements, you’ll find an article written by yours truly in the November, 1989 issue of Astronomy magazine on the subject of building a Dobsonian telescope.

Now that I am retired from my professional engineering life, I’ve found that I can spend more time viewing the skies through my telescopes. (Yes, that is plural. I’m afraid I’m slightly on the lunatic fringe of the hobby, pun intended.) Photos from NASA’s Lunar Reconnaissance Orbiter, showing the Apollo landing sites from an altitude of 50 miles, inspired me to search for the lander locations using my telescopes. And, with a subtle nudge from my older son Adam is the inspiration for this book.

The intent of this book is twofold: to serve as a visual guide, stepping the reader through a process for locating and viewing the Apollo landing sites, and an appreciation of what was accomplished there. The reader should look elsewhere for a more historical accounting of the Apollo Program, as there are many fabulous books on the subject written by former Apollo astronauts, Apollo flight controllers, engineers, and other well-known authors. There is a conscious informality that I’ve used in referring to the astronauts and their missions and equipment. This book serves as an observational guide, allowing the casual and serious observer a chance to locate the Apollo landing sites visually (with or without visual aid), and appreci­ate the historic experiments and equipment left behind. A review of the scientific results is included, and interestingly enough new knowledge is being added about the Moon from Apollo data to this day!

Also included are photos from the lunar probes leading up to Apollo. The long – forgotten Ranger series and the Surveyor series of lunar probes provided valuable information to NASA, both in terms of science and in terms of engineering require­ments and techniques needed to getting to the Moon.

Maybe someday in the future, Mankind can reach out to the Moon again. And provide a reason for a Volume 2 to this book.

Подпись: James L. ChenGore, VA January 25, 2014


The development of the Saturn-V rocket was key to the success of the Apollo pro­gram. The accomplishments of Werhner Von Braun and his team of German and American engineers are undeniable. The liquid rocket technology that began with the early efforts of Robert Goddard in the 1920s, the wartime development of the A-4 and V-2 missiles of World War 2 Germany under Von Braun’s leadership, the continuing development of ballistic missiles through the Cold War years of the 1950s and 1960s, led to the crowning achievement of the Saturn-V.

Current rocket propulsion technology does have its limitations. Using current rocket technology for Moon travel has been demonstrably practical. However, lon­ger trips into space beyond the Moon and within the Solar System demonstrates the limitations of current technology. Just to travel within the confines of the Solar System demands a staggering amount of fuel and rocket power for direct trips to adjacent planets. Deep space probes, such as Cassini, Galileo, and New Horizons, takes years of planning and reliance on planetary gravity assists to achieve the goals of the designed missions. Any manned mission to Mars and return to Earth becomes a multi-year effort, with considerable scientific, technological, logistical, and human health risks involved. Any attempt to travel to Mars with current rocket technology becomes an extraordinary expensive proposition.

Truth be known, a new propulsion technology is needed. If years of space travel can be cut to months, or even days, an attempt at Mars becomes more than a pipe dream. Unmanned probes, such as the Mars Orbiter, and the aforementioned Mars rovers are laying the groundwork, just as Ranger and Surveyor did for the Apollo program. Current propulsion technology works for remote probes, robotic landers, and rovers. But the exposure to the harsh realities of space renders a manned Mars mission a very risky business.

Like the chemical liquid fueled launch vehicles that NASA and the rest of the world relies on now, alternative space drive systems have been in slow development for over a century. Propulsion systems utilizing ion/plasma reaction engines have been proposed, with several designs undergoing some form of development.

The most promising of these alternative drive systems is the Variable Specific Impulse Magnetoplasma Rocket, or VASIMR. VASIMR uses radio waves to ionize and heat argon gas, and subjects the ionized argon to magnetic fields in order to accelerate the resulting plasma which provides thrust to a space vehicle. This plasma rocket technology was first introduced in 1977 by Franklin Chang Diaz, a Costa Rican scientist and astronaut.

A VASIMR driven spacecraft will allow for a mission to Mars with a travel period of just 39 days, almost 6 times faster than current rocket technology. The VASIMR driven spacecraft can develop speeds estimated at 35 miles a second, and will conceivably cover the distance between Earth and Mars in a more timely manner.

NASA rates new systems on a scale of one to ten based on its readiness to be deployed. The VASIMR system is currently rated by NASA as a six, which means that testing in space is the next step. NASA is testing a 200-kW VASIMR engine on the International Space Station in 2015. The engine is envisioned to provide periodic boosts to the ISS, which gradually drops in altitude due to atmospheric drag. ISS boosts are currently provided by spacecraft with conventional rocket thrusters, that consume about 7.5 tons of fuel per year. By cutting fuel use down to 0.3 ton per year, a huge cost saving can be realized in ISS operations. A success for VASIMR on the ISS will lead to a possible Mars application, with a nuclear reactor approximately equivalent to those carried aboard nuclear submarines. A reactor capable of generating 10-12 MW of power is required. Dr. Franklin Chang Diaz stated in a paper called The VASIMR Rocket which appeared in the November 2000 issue of Scientific American, that a 10-12 MW nuclear reactor is required for a 39 day journey from Earth to Mars. In addition, on September 29, 2009 Dr. Franklin Chang Diaz stated the following. “In fact, with the power close to what a nuclear submarine generates, you could use VASIMR to fly humans to Mars in 39 days.”

The Filters

As the Moon waxes towards its full phase, the image through a telescope becomes uncomfortably bright. Not dangerously bright as with the Sun. Just so bright that the viewing can become difficult to identify areas on the Moon without squinting.

There are a number of filters available to telescope owners, such as nebula fil­ters, light pollution filters, and color filters. These filters are very useful in many applications where the goal is to reveal very dim low contrast objects and features. But viewing the very bright Moon does not require these sophisticated accessories. The goal of using neutral density filters is to dim the light entering the eyepiece without any major degradation of image quality. With two polarizing filters, the same can be accomplished. By turning the filters in respect to each other, the amount of filtering can be adjusted.

It is recommended that one or two neutral density filters or polarizing filters be available to cut down the intensity of the incoming moonlight. These filters conve­niently screw onto the bottom of the eyepiece. They cost less than $20, and are well worth the investment.

The Mounts

The Filters

Fig. 2.16 The Author’s telescopes featuring an Alt-Az with Slow Motion Controls, two German Equatorials, and Computerized GOTO Mount. Courtesy of the author

A solid telescope mount completes the total system needed for viewing the Moon, and beyond. There are two basic flavors of mounts: the altitude-azimuth mount, mostly referred to as the Alt-Azimuth or AltAz mount; and the equatorial mount. Each type can come either as manual, driven by hand controls or motors, and computer-driven GoTo models. Equatorial mounts and some computer-driven mounts compensate for the Earth’s rotation and will track the Moon, planet, or other celestial object, thereby keeping the object in the field of view of the telescope.

The Filters

Fig. 2.17 AltAzimuth mount with slow motion controls. Courtesy of the author

The most intuitive and easiest telescope mount is the altazimuth mount. Right – left and up and down. Simple in operation. In fact, it’s the perfect mount for young people to use. Four year old kids have been seen at star parties using a refractor on an alt-az mount viewing the Moon with little supervision. Altazimuth mounts are considerably lighter than equatorial mounts, and are therefore well suited for grab – and-go scopes or for traveling. No set up is needed. The main drawback is the lack of tracking. The observer manually adjusts the positioning of the telescope, becom­ing the human tracking motors!

The Filters

Fig. 2.18 The Dobsonian Mount. Courtesy of Gary Hand

A notable example of an alt-azimuth mount is the implementation made famous by John Dobson in the early 1980s. Known as the Dobsonian mount (with the entire assembly including the Newtonian telescope being referred to as the Dobsonian telescope), is a simple, low center of gravity alt-azimuth mount made of wood and Teflon bearings. The Dobsonian caused a resurgence in homemade telescopes in the 1980s and 1990s. In today’s market, telescope manufacturers dominate the 12-in. Dobsonian and smaller sizes because of the economies of scale. Larger sizes are economically attractive for homebuilt projects, and for those with the funds, can be obtained as commercially produced telescopes. The Newtonian telescope on a Dobsonian mount offers by far the biggest “bang-for-the-buck”. But they are big, bulky, and the Newtonian optics still requires frequent alignment. For Moon and planetary use, Dobsonians are not recommended for the mechanically challenged.

The Filters

Fig. 2.19 German Equatorial Mount. Courtesy of the author

With the exception of fork mounted Schmidt – and Maksutov-Cassegrains, the most popular form of equatorial mount in the amateur world is the German equato­rial. The German mount is a tilted axis contraption with the right ascension axis pointed and aligned in the direction of the North Pole (for those down-under, the South Pole). A tracking motor applied to the right ascension axis drives the mount to keep the observed object in the eyepiece. German equatorial mounts are awk­ward and heavy. Care must be taken to balance the telescope on the mount, which explains the presence of the large counterweight that is a characteristic of the design. And polar aligning of this mount can be a chore. But if astrophotography is a goal, the German mount is a necessity.

The Filters

Fig. 2.20 Computer GoTo Mounted Schmidt-Cassegrain. Courtesy of the author

A GoTo telescope mount is quite simply a telescope system that is able to find celestial objects in the night sky, and then track them. The GoTo mount can be set up in an alt-azimuth or equatorial fashion, and after the proper alignment proce­dure, the finderscope is not needed for the rest of the evening. Some of the newer GoTo telescopes have electronics that will perform the alignment procedure automatically.

These telescope mounts are wonderful pieces of technology. The GoTo technol­ogy allows for more efficient use of observing time by quickly finding objects in the night sky. Built into the hand controller is a microprocessor, firmware, and built-in memory catalog of the positions of thousands of stars, galaxies, nebulae, open star clusters, globular clusters, planetary nebulae, our solar system planets, and of course the Moon. And the Moon is the one object that does not need a com­puter assist to find.

There is a tradeoff when buying a GoTo mount. These mounts are not cheap. Often consumers are faced with the dilemma of either a smaller telescope with a GoTo mount, or a larger aperture telescope on a non-computerized mount. In the case of viewing the Moon, a GoTo mount is not needed. If you can’t find the Moon, it’s either during the new moon phase, or you’ve got other problems! The Moon is an easy target.

A tip to GoTo owners: When using a telescope on an alt-azimuth GoTo mount, always use Polaris as one of your alignment stars. The computer algorithm used in programming the mount goes through less mathematical gymnastics when aligning with declination 0°, right ascension 0°. The GoTo accuracy is improved tenfold.

Author’s Telescope. Equipment. Used for This Book

The initial thought in the creation of this book was to use 100 % NASA produced photographs from full moon, to the zoom-in shots, to LRO photos, and to Apollo astronaut shots.

But as the book evolved, to produce the view that a backyard observer would see, it became a necessity and challenge to produce lunar photographs of the full moon and the telescopic views myself.

I own several telescopes that are capable of producing outstanding lunar images, and I initially used three refractors of mine: a 94 mm and a 130 mm Brandon apo – chromatic refractors, and a 102 mm Stellarvue 102ED refractor. Since refractors produce the sharpest and most contrast images, I felt the aperture ranges were representative of telescopes commonly owned by potential readers of this book.

The two Brandon refractors are legendary late-1980s telescopes and highly sought after, since at their heart are Astro-Physics triplet apochromatic objectives. Both Brandon refractors are mounted on Vixen German equatorial mounts, with the 94 mm on a 1980s vintage Super Polaris mount with right-ascension drive and manual declination drive, and the 130 mm on a Vixen Sphinx SXW dual-axis drives and computerized STAR Book control. The challenging aspect of using these tele­scopes are their somewhat archaic Unitron rack-and-pinion focusers, which for visual use are perfectly adequate, but for photographic use lacks finesse and made high magnification fine focusing challenging. Prime focus projection was used for full Moon photos using these telescopes.

The Stellarvue 102ED is a more recent late-2000s vintage, using modern low – dispersion ED glass and a two-speed Crayford focuser. The two-speed Crayford focuser facilitated fine focusing for the higher magnification photographs. Higher magnifications were achieved using Barlow lens projection in combination with extension tubes. The Stellarvue 102ED is mounted on a common mid-priced CG-4

German equatorial mount with dual-axis drives. Although the CG-4 lacked the sophistication of the Vixen mounts, the short exposures used in producing lunar photos did not require high precision or any fine adjusting guidance from the mount.

An affordable digital single lens reflex, or DSLR, camera was used. A Canon XTi DSLR equipped with the appropriate T-mount and T-adapter was used. Exposures ranged from as short as 1/800 second for full Moon shots to 1/60 second for the gibbous Moon. Initially, the photos were jpg-compressed, but as experience with the camera-telescope combination was gained, the RAW format was used to facilitate post-processing of the photos using RegiStax and Photoshop software.

In the end, I found the Stellarvue produced the best photographs, mostly the result of the combination of high quality optics with a excellent dual speed Crayford focuser. All of the author’ produced photos in this book are the result of several clear evenings during February and March, 2012 using the Stellarvue 102ED and the Canon XTi DSLR. Post-processing of the digital images were per­formed on an Apple iMac using Adobe Photoshop.