It's a full moon! Should you get out there with the werewolves?

The full moon bothers a lot of amateur astronomers and I used to just plain hate it. First, I read too many horror comic books while sitting in the barbershop as a kid, so werewolves do bother me – but I find if you ignore them, they tend to stay away. But as Clay Cooper notes in a recent email, there are other good reasons for amateur astronomers to avoid the full – or near-full – moon.

I've had a couple of short observing sessions this week, but the moon's light is now washing everything out too much for any meaningful stellar work. You must schedule your public sessions to avoid the brightly light moon times too, I would imagine. I enjoy looking at the moon too, but once it gets this full and beyond, the detail just isn't there because the light is hitting it too directly. Many people have the false belief that the full moon is the best time to observe the moon because you can see ALL of it - nothing could be further from the truth.

Agreed! Clay's absolutely right . . . but, for years I took this too literally. I simply cursed the moon and abandoned observing during these times. Doing the public programs has given me a fresh perspective and the full moon no longer stops me from enjoying the rest of the universe, though it does limit my targets. Yes, I do public sessions during full moon and the days close to it. Why?

The moon itself takes on a special interest at this time of month. For newcomers - my typical visitors - it's a good time to learn the general layout of "seas" and mountain ranges. It's also a good time to look for rays and try to determine which craters have the most and which are the longest - and how long is long - and what is a ray, anyways? Quite fantastic stuff, really, when you understand what caused a ray. I also ask folks to identify the three brightest spots on the moon. I don't really care if they get the brightest or not - but what they do in looking for them is to really begin to notice how many different gradations of brightness there are - and this leads to natural questions about why. And - why are some areas truly brilliant?

But there are other observing activities that may actually be enhanced – or at least not hindered – by the washed out background. One area I have been pursuing at full moon is double stars. It seems to me there are two advantages -

First, I think some are easier to split against a moonlit sky, then against a fully black sky. The moonlight seems to cut back on the glare from the star. I haven't put this to a scientific test - but that's my experience. (Same reason why you can frequently see the form of Venus in early twilight, but as it gets darker, it becomes more difficult to see because of the glare from the planet's clouds.)

Second - and this gets into a controversial area - I think it's easier to make out color when the contrast is cut a little. I first started to notice this when my public sessions forced me into doing two-star alignments as soon as it was dark enough to see the brightest stars so I would be ready when people arrived. No, I didn't align on doubles, but I do frequently choose a star with a lot of color. So suddenly I found myself looking at stars such as Arcturus in the 15-inch during bright twilight - and my impression was it had never looked so orange! Color really shows in these conditions – or at least that's my impression.

Then, of course, there are planets which are bright enough not to be seriously limited by the moon,

And finally, it's a good time to learn the constellations. No kidding. Too many stars confuse you. Get into Mag 4 skies and it's easier to pick out the major constellations.

Hmmmm . . . this might even be a good time to go looking for asteroids. Losing all those background stars isn't the end of the world. It can make some tasks easier.

Oh, and one more thing – the brightly moonlit sky can be a great time for equipment testing and tune up without wasting those truely dark nights for doing this sort of thing.

Ummmm... forgot variables . .. some experiecned observer may contradict me on this. I haven't done serious variable star observing in years. But if I remember correclty, you don't want the biggest telescope to do variable work - you want the variable to be somewhere near - not at - the limit of your scope. So given moonlight conditions you may have to bring out a larger scope for a given variable, but why not make your observations under these conditions. The key requirement is to be able to compare the brightness of one star with another and it seems they would all be impacted the same by the moon, so . . . well - maybe this isn't a good idea for serious observers reporting results? I don't know. But certainly for casual observers who simply want to learn about variables, it should not cause a problem.

Wonder if anyone has other ideas about observing under a full mon? Email your suggestions and I'd be happy to post them here. (gstone@umassd.edu)