Appendix A Luna and Telescopes Exploring Luna’s surface is one of the easiest things to do in this book. You have a few options when you do this. It has the advan- tage of being the only moon visible to the naked eyes. (You might be able to just see the Galilean moons, but you would hardly be able to do anything beyond just see them.) So the next step is to consider an instrument. Be aware, this is not a general purpose guide. If you want one, look at the local library or bookseller for a copy of “NightWatch” as the book is excellent, has a sturdy plastic spiral for easy hands- free use and will serve you in more ways than just binoculars for many years to come. That being said all my recommendations in this chapter are for viewing ONLY OUR MOON. Most other moons will be pinpricks, so if you can see them at all you did the best you could. If you also wish to view nebula, galaxies, birds, be rude to your neighbors, and so forth, do your homework. Binoculars The first option is to go with binoculars. These come in a variety of sizes, which is listed as two numbers. The first is magnification and the second is aperture size (in mm). Common sizes include 7 × 35, 7 × 42, 8 × 40, 9 × 50 or even 10 × 50. For dim object you will want the bigger sizes, but the moon is not a dim object. Even a 7 × 35 will produce some pretty spectacular views. If you do buy binoculars, go with a good company. More on this is under telescopes. © Springer International Publishing Switzerland 2016 231 J.A. Hall III, Moons of the Solar System, Astronomers’ Universe, DOI 10.1007/978-3-319-20636-3 232 Appendix A Luna and Telescopes If you intend to use binoculars you should ask yourself how. Some people try to stand up and use them and feel light-headed pretty quick as well as arm pain. Some people like to lie in a lawn chair and do it which makes it easier but not easy. The best choice here is to use a sturdy tripod (most binoculars have a mounting hole in the bottom), and to get a pair of 45° or 90° diagonals (required for standing, and standing is certainly easier). If you are a do-it-yourself- er you can even build a custom mount, that will hold the binocu- lars in place so you can look in them and then look away without touching them. For instance, you could mount them over the head of a reclining lawn chair, or even mount them on a swing table that pivots around you on an upright lawn chair (and with a large enough table you can have a guidebook or sketchbook too.) One thing that you may see at some more recent star parties is to use an inflatable pool dinghy, as it provides better neck and shoulder support them most lawn furniture does. (Larger magnification gives a narrower field of view, but we are discussing the moon.) If you are using a tripod you can also use big binoculars. What is big? 10 × 50, 11 × 80, 15 × 80, 16 × 70, and 20 × 80 all exist. 10 × 50s can weigh less than 2 lbs./0.75 kg. 11 × 80 can weigh 5 lbs./2.25 kg or more! I don’t think you want to hold a 2 or 3 kg dumbbell over your eyes for an hour or more. Telescopes If you want to get a lot of magnification, you may need to use a telescope. I evaluate telescopes for three criteria: price, light site viewing, and quality for moon seeing. Now, the most important thing if considering a telescope is quality. I bought a “Galileo”-brand telescope with some impressive accessories off one of those home shopping TV stations for about $100. It came with an 8 mm eyepiece, and two others, a Barlow and sun projection plates. The tube was of inferior quality the objective lens was substandard. The 8 mm eyepiece has a small lens that was not fitted properly. The tripod was a steel tripod, with inline screws for the legs, and actually was of pretty good quality, at least Appendix A Luna and Telescopes 233 for an altazimuth. I could see the moon and the Pleiades, and proj- ect the sun but that was about it. The whole shebang was sold at a moving sale for about $15 (since the tripod was of good quality). Buy a telescope from a good company. Who is good? Meade, Celestron, Astro-physics, Televue, and Vixen. There are others too, but the best place to ask is a local planetarium if you are lucky enough to live near one, or you could go to any university. If they do not have an astronomy department try Physics. Avoid telescopes from Chinese factories (since they make 90 % of the trash scopes), but some Japanese companies also make a very good selection. Takahashi and Caton are well known. And yes, you do get what you pay for. If you pay 15,000 for a Meade, you will get more than the $100 “Department store XYZ Christmas Special.” It also helps if you have an assistant. Telescope stores are bet- ter than department stores. If you make friends at star parties or astronomy clubs, one of them may wish to help you on your way. Books can also be helpful. Also give a thought to accessories. Your tripod should be sturdy, but an altazimuth is often sufficient for the moon. Erecting prisms can be useful if you are using a refractor. Reflectors often do not require them. Neutral-color lunar filter are essential for bright moons, like the type you will come up against during full moon. If you intend to image you will need a CCD or DSLR, but there are entire books just on the subject of astrophotography. Computer controls will likely not be required; if the moon is up, you can usually tell without a computer telling you… If you have an equatorial, you can have a motor drive follow the moon, but an equatorial is not required for lunar viewing, neither do you require setting circles. A motorized focuser should be used if you have one and wish to. This is a person-to-person decision. So, what type of scope is best for the viewing the moon from a bright site which does not require a second or third mortgage? Apochromatic Refractors Ratings : Price : 2 ; Performance : 10 ; Light : 7 ( Overall : 6.3/10, due to price, 8.5 otherwise ) In the 3–7″ (80–180 mm) range these provide the best result. This is the preferred choice if you can afford one. This works well in 234 Appendix A Luna and Telescopes a bright site, and outperforms achromatics in a dark site. If you are limited to mostly urban viewing this is still a good choice. A good one can run from $2000–3000 for a 100 mm apochromatic with sturdy equatorial mount. This is the best, but out of price for most— this would be fine if the planets and moons were you career choice. Maksutov-Cassegrains Ratings : Price : ETX : 7 ; Questar : 0 ; Performance : 9 ; Light : 8 ( Overall : ETX : 8/10, Questar : 5.7/10 due to price ) In the 3.5–7″ (85–180 mm) range these provide excellent results (second only to Apochromatic Refractors) if you have a good model. This works good-very good in a bright site. Price will limit you. The Meade ETX will stay under $1000. A well- maintained Questar will cost about $4000. Achromatic Refractors Ratings : Price : 5 – 9 ; Performance : 9 ; Light : 7 ( Overall : 7.7/10 ) In the 2.4–4″ (60–100 mm) range these provide excellent results (for the moon). You may wish to use a longer focal length, f/9–f/16. You telescope dealer or assistant (if he knows what he is doing) will be able to help you with this. This works well in a bright site, but underperforms in a dark site. These run from $500–$1000 (at the upper end with a sturdy mount). Small ones can be under $500 but check the mount. These can run from $1000–$1500 for top quality models (like a Meade or Celestron 4″ with an equato- rial mount.) Small Newtonian Refl ector, Equatorial Mount Ratings : Price : 9 ; Performance : 7 ; Light : 7 ( Overall : 7.7/10 ) In the 4–8″ (100–200 mm) range these provide good results (for moons). This works well in any site. You may get a small one for under $500 but check the mount. Schmidt-Cassegrains Ratings : Price : 0 – 5 ; Performance : 7 ; Light : 7 ( Overall : 5.5/10 ) Appendix A Luna and Telescopes 235 In the 4–8″ (100–200 mm) range these provide good results. This works well in any site. These run up $1000–$1500 or can be $1500–$2500. Look at the options you’re paying for (since com- puter control is likely included on the higher priced ones). 8″ ones can even run up to $4000. Large Newtonian Refl ector, Equatorial Mount Ratings : Price : 5 ; Performance : 7 ; Light : 4 ( Overall : 5.3/10 ) In the >10″ (>250 mm) range these provide good result. Use a focal length of f/6–f/8 for best results. This is rather limited in bright sites. These will probably run you $500–$1000 Small Newtonian Refl ector, Dobsonian Mount Ratings : Price : 9 ; Performance : 6 ; Light : 7 ( Overall : 7.3/10 ) In the 4–8″ (100–200 mm) range these provide good results, but the mounts are not designed for viewing moons and planets— they don’t move too easily.