Here are five more tips that will help you maximize your lunar viewing.
On July 19, 2016, the Full Moon rose over the dome of the famous 100-inch Hooker Telescope atop Mount Wilson, California. The 100-inch dome stands at right, and to the left is the dome of one of the six telescopes that together form the CHARA interferometer.
Credit: John Fisanotti
Recently, I posted the first part of this list, which you can find here. This is part 2.
6. Cut down the moonlight
Many observers use either neutral density filters or variable polarizing filters to reduce the Moon’s light. I prefer the latter because an observer can change how much light the filter transmits. Two other ways to reduce the Moon’s brightness are to use high magnification or to add an aperture mask. High powers restrict the field of view, thereby reducing light throughput. An aperture mask causes your telescope to act like a much smaller instrument, but at the same focal length.
7. Turn on your best vision
Some years ago, my late observing buddy Jeff Medkeff introduced me to a better way of observing the Moon: Turn on a white light behind you when you observe between Quarter and Full phases. The light should be moderately bright (I suggest something in the 60-watt range), but neither your eyes nor the eyepiece should be in direct view of it. The addition of white light will suppress your eyes’ tendency to dark adapt at night. Not dark adapting causes the eye to use normal daytime vision, which is of much higher quality than dark-adapted night vision. In essence, you’ll see more detail because you’re viewing with a better part of your eye.
8. Work from a list
One of the best ways to learn the Moon is to undertake an observing project. In the U.S., the Astronomical League offers two such projects, the Lunar Observing Program and the Lunar Evolution Observing Program. You’ll learn a lot about our satellite as you work through these lists. To receive a certificate, you must be a member of the league, either individually or through an astronomy club. For details about these two projects, go (here – https://www.astroleague.org/lunar-observing-program/) and (here – https://www.astroleague.org/lunar-evolution-observing-program/).
9. Dig for the details
Of the 1,940 named lunar features, 1,545 are craters. Challenge yourself to see either 1) how small a crater you can detect or 2) how many craterlets (small craters in and around larger ones) in a given area you can observe. You’ll need a detailed Moon map for this project. For the second challenge, you can choose a lunar sea, but usually a large, flat-bottomed crater works best. For example, if you search the large crater Plato, you’ll find four craterlets on its floor, each about 1.2 miles (2 kilometers) across. Lunar observers consider seeing these craters a test for a 6-inch telescope.
10. Shoot the Moon
How can a celestial object that’s so easy to photograph be so difficult to photograph well? The Moon is large and bright (only the Sun outshines it), and you can use any camera connected to any size telescope to image it. That’s the easy part. But the Moon also contains vast areas of low contrast that don’t differ much in color or brightness. Recording those regions so they look like what your eyes see is the hard part. Luckily, we live in the digital age. Unlike when astrophotographers used film, it costs nothing extra to take 200 images instead of just one. Examine them, throw away what you don’t like, change one or more parameters (including the techniques you used to process the images), and shoot some more as you continue to perfect your techniques.
