Category How to Find the Apollo Landing Sites

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

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 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!

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.

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.

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.

The soil mechanics investigation was performed by the surface sampler carried on Surveyor 3 and 7. The sampler proved to be an extremely versatile and useful piece of equipment. Using this device, operators performed a number of bearing and impact tests and trenching operations. All these operations were monitored using the television camera, and photography of the results provided information for this investigation. This type of scientific investigation also continued during the Apollo missions, as Apollo crews performed many observational and sampling tasks related to soil mechanics.

Lunar Surface Electromagnetic Properties

Surveyor 5, 6, and 7 had a magnet attached to one of the spacecraft footpads to determine magnetic properties and composition of the soil. Surveyor 7 had addi­tional magnets on a second footpad and the surface sampler. Photographs showing the amount of dust adhering to magnets indicated the amount of magnetic particles in the soil and allowed estimates of the lunar soil compositions when compared with pre-mission experiment photographs of magnets in terrestrial soils of various compositions. On a larger scale, the ALSEP suite of the Apollo missions carried a lunar surface magnetometer to measure the strength of the Moon’s magnetic field.

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.

The majority of telescope owners make their observations through an eyepiece using one eye. The human brain is designed to process visual images through two eyes. There are two options for viewing the Moon, the planets and stars with two eyes. One is REALLY expensive – binocular telescopes. The other option is rela­tively affordable – the binoviewer. The binoviewer uses a system of prisms to split the single light path of a telescope into two separate light paths to two eyepieces. This beam-splitting fools the eyes and the brain into thinking it is seeing an object in stereo. The results are spectacular when viewing the Moon. At certain high mag­nifications, and by allowing the Moon to drift through the field-of-view, the observer gets the sensation of orbiting the Moon and seeing the view that the Apollo command module pilot would see in orbit. With both eyes open, the lunar landscape seems to glide smoothly past. Even when tracking, the lunar landscape seems to take on three dimensions. The downside to owning a binoviewer is threefold:

• There is a slight light loss using a binoviewer because of the additional light splitting optics. But for a bright object like the Moon, this is not a problem. For planetary views, the light loss is not of great impact. Deep sky observing can be problematic, especially with dim objects.

• There is the additional expense of the binoviewer and buying two of every eye­piece. And you are limited to 1.25 in. sized eyepieces.

• Many telescopes do not have enough in-focus to accommodate a binoviewer. SCTs and Maks focus by moving the primary mirror and binoviewers work well with these types. Some refractors are manufactured with shorter tubes to accom­modate the binoviewer, and provide extension tubes to use for mono viewing. Many binoviewers have an optional Barlow-like attachment to allow focusing with other types of telescopes, which limits the low power magnification range.

Composition of surface materials was also determined from data obtained by the alpha-scattering instrument. The alpha-scattering surface analyzer was designed to measure directly the abundances of the major elements of the lunar surface.

This instrument was carried by Surveyor 5, 6, and 7 to allow chemical analysis of the lunar surface material. The alpha-scattering surface analyzer performed as designed, and provided excellent data. From the three Surveyor spacecraft that carried the alpha-scattering surface analyzer, six lunar samples were examined. The Surveyor 5, 6, and 7 missions provided the first chemical analysis of lunar surface material.

In summary, five Surveyor spacecraft landed successfully on the lunar surface. Four of these examined widely separated mare sites in the Moon’s equatorial belt. The fifth investigated a region within the southern highlands. Four spacecraft sur­vived the extreme cold of the lunar night and operated for more than one day/night cycle. In total, the five spacecraft operated for a combined elapsed time of about 17 months, transmitted 87,000 pictures, performed 6 separate chemical analyses of surface and near-surface samples, dug into and otherwise manipulated and tested lunar material, measured its mechanical properties, and obtained a wide variety of other data that greatly increased our knowledge of the Moon.