Last
night was the latest so-called “Supermoon”. Yes, I know you’re not supposed to be
able to discern any difference in angular size from a “normal” Full Moon, but I’d
swear the naked eye can detect a difference in apparent magnitude. The dang
thing was like an automobile headlight up there! Anyway, it got me to thinking
about something I had written more than 4 years ago. I thought those words
would be a great place from which to start the next series of postings, which
are going to (largely) be about observing the Moon. Here they are (from April 7th, 2012):
Went
out last night to take a look at the moon. Yes, the full moon - big as a dinner
plate, almost too bright to look at even with your naked eye, washing out the
stars and casting shadows on the brightly-lit ground. That moon.
Is there anything to see in a full moon? Most people assume not, and keep their scopes locked up until the damn thing goes away. Well, I felt like challenging that conventional wisdom, and took a good, hard look. Here is what I saw:
Is there anything to see in a full moon? Most people assume not, and keep their scopes locked up until the damn thing goes away. Well, I felt like challenging that conventional wisdom, and took a good, hard look. Here is what I saw:
1. Rays. Lot's of 'em! Mainly from Tycho, Copernicus, and Kepler, but also from
at least a dozen less notable craters. We so often admire images of the great
lunar crater rays, but all too seldom actually look at them with our own two
eyes. They can only be seen at or near the full moon, and are well worth the
effort it takes to observe them. Beautiful!
2. Thanks to a favorable libration, I had a terrific view of part of the lunar
farside, the Mare Humboldtianum. This "sea" is best seen when all the
shadows are gone, and the dark mare material really stands out against the
highlands background.
3. Great view of the lunar North Pole. Many people do not realize that there is
actually no such thing as a true "full moon" - ever. The only time
the moon is directly opposite the sun is during a total lunar eclipse. Most of
the time, our satellite passes either above or below the Earth's shadow, so
even at so-called full moon there is still a terminator. It will be at either
the North or the South Pole. Last night it was in the north. Terrific view of
the edge-on craters Pythagoras and Anaximenes - two locations that deserve more
attention from amateur astronomers.
4. Proclus. This result of an oblique impact is best observed at full moon,
when its definitely odd ray pattern really stands out. You can easily visualize
the approaching asteroid coming in at a very shallow angle from the west, and
splattering debris in a most unique pattern.
6. For a challenge, I tried making out the Alpine Valley, and found it! Even in the absence of all shadows, you could still see it thanks to the dark lava that welled up to cover its floor.
7. Made note that the eastern maria (Tranquillitatis, Serenitatis, Crisium,
etc.) were, as a group, noticeably darker than the western ones (Imbrium,
Procellarum, etc.). Made me wonder... is this actually so, or is it an optical
illusion? (The eastern maria are generally smaller than the western ones, so perhaps
the increased contrast with their surroundings is more noticeable, making them
appear darker.)
8. I discovered that Aristarchus is not the only superbright crater on the
moon. There are literally dozens of them at full moon, scattered all over the
lunar disk.
9. Some crater walls at full moon appear as brilliant rings of light. Best
example was Julius Caesar, near the Sea of Tranquility. But there were many
others as well.
10. The weird albedo feature in Oceanus Procellarum, the Reiner Gamma, stood out
clearly. A fascinating sight!
So see? There's lots to look at on the full moon. You've just lost one more excuse for staying indoors on a cloudless night!
So see? There's lots to look at on the full moon. You've just lost one more excuse for staying indoors on a cloudless night!
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