Mountain ranges, volcanic plains, and lots of craters make the Moon a target you’ll return to again and again.
As his telescope cooled to ambient temperature October 22, 2017, this photographer set up a camera on a tripod and captured the scope, its observatory, and the waxing crescent Moon.
Credit: Jared Bowens
- Initial lunar observation should begin with unaided-eye familiarization of major features, followed by binocular observation for enhanced detail identification.
- Optimal lunar viewing occurs during periods shortly after New Moon and before First Quarter, and around Last Quarter, due to increased shadow contrast and atmospheric stability.
- The lunar terminator, the boundary between light and dark portions, offers the best viewing opportunities as it reveals topographic features in sharp relief.
- A variety of telescopes, including refractors, reflectors, and Schmidt-Cassegrains, are suitable for lunar observation, with telescope selection often influenced by ease of repeated use.
The Moon offers something for every amateur astronomer. It’s visible somewhere in the sky most nights, its changing face presents features one night not seen the previous night, and it doesn’t take an expensive setup to enjoy it. To help you get the most out of viewing the Moon, I’ve developed some simple tips. Follow them, and you’ll be on your way to a lifetime of satisfying lunar observing. I’ve divided these tips into two lists of five. Here’s the first one.
1. Perform a “no optics” survey
The best way to begin your journey as a lunar observer is to learn the Moon’s major features. Head out near the time of a Full Moon with a simple Moon map. Then, use just your eyes to identify our only natural satellite’s most visible features. Once you learn the Moon’s overall layout, introduce binoculars and identify more (smaller, but still large) features.
2. The Full Moon is for romance
Contrary to what you might think, Full Moon is not the best time to observe our natural satellite, although that’s the time when it’s at its brightest. When the Moon is full, the Sun lies behind Earth (as we face the Moon) shining directly down on the lunar surface. Shadows are at their minimum lengths, and you can’t see much detail. You can still observe the Moon when it’s full, but the contrast between its light and dark sections will be better at other times.
3. View the Moon at “prime time”
Two intervals during the lunar “month” (from one New Moon to the next) are best for observers. The first begins shortly after New Moon and continues until two days past First Quarter. Amateur astronomers tend to favor this span because the Moon lies in the evening sky. An equally good observing period starts about two days before Last Quarter and goes until the Moon lies so close to the Sun that it’s lost in morning twilight. At these times, shadows are longer and features stand out in sharp relief. Another benefit you’ll get when you observe the Last Quarter Moon is that the atmosphere before dawn usually appears steadier than it does after sunset. After sunset, a lot of heat remains in the atmosphere. As hot air rises and cooler air falls, the resulting turbulence leads to unstable air — what observers call bad seeing.
4. The terminator will help you
During the two favorable periods described in my third tip, point your telescope anywhere along the line that divides the Moon’s light and dark portions. Astronomers call this line the terminator. Before Full Moon, the terminator marks where sunrise is occurring. After Full Moon, sunset happens along the terminator. Here you can catch the tops of mountains protruding just high enough to catch the Sun’s light while surrounded by lower terrain that remains in shadow. Features along the terminator change while you’re watching them, and, during a night’s observing, the differences you’ll see through your telescope will be striking.
5. The best scope for viewing the Moon
Nearly any telescope will do to observe lunar details. You’ll get great views of the Moon through a 2.4-inch refractor, an 8-inch reflector, or an 11-inch Schmidt-Cassegrain telescope. Observers with several options (but not a permanent observatory) usually pick a scope they can set up many nights in a row. Observing on successive nights makes it easier to follow the terminator’s progress.
