Light Site Viewing - Part 3

Joe Shuster

In parts 1 and 2 I presented the idea and characteristics of the new LCAS "moon parties" at light sites. These events should let us introduce a lot of adults and kids to astronomy in a way that complements our traditional star parties at the Volo Bog or at other sites like schools.

As a club, we know how to deliver a star party because we have a lot of experience under our belts. We can support new members at star parties with that same experience. However, we don't have as much practice at events at light sites. And as we learned in the earlier sections, our tactics need to be different.

So how to we prepare for a moon party? Well the easy answer is "Know a lot about the moon." It's amazing how little many experienced astronomers know about the moon. We should be able to point out maria, mountain ranges and major craters. It's good to be able to discuss some of the other interesting aspects of the moon such as its size, orbit, distance, origin, etc. But those are less critical issues. Just use the traditional mantra of product demonstrators: Show what you know and know what you show.

You can easily prepare with books or on-line. The first step is to determine what parts of the moon will be illuminated at the time of the star party. There are lunar phase simulators on-line at NASA ( and at an eclectic Swiss site ( Plug in the time and date and these will show you the general view of the moon. You'll be showing things near the terminator (or just east of the terminator) so note where the terminator lies on the moon.

There are some nice lunar atlases. I like Rukl's "Atlas of the Moon", recently republished from Sky Publishing. His narratives can be awkward to read, possibility due to translation issues. However the maps are really nice. You can track the terminator and learn a few names of craters, seas or other features, like Straight Wall.

If you want to learn from software, you can buy a lunar atlas software product or you can use the free Virtual Moon Atlas from the same author as Cartes du Ciel, Patrick Chevalley. This is a fine product that can be adjusted to show the phase of the moon on any date. You can read Jack Kramer's fine review of VMA from the April 2005 Night Times at or search the on-line club archives for "virtual moon atlas".

For your first moon party, be happy if you can identify 10 different items on the moon that are have good illumination and shadowing. But you might want to be more conversant and expert on the moon. There are countless websites for more information. There's Inconstant Moon, the Wiki encyclopedia, the American Lunar Society, get the picture. Pick up a little at a time and you'll be a certified "lunatic" after just a few moon parties.

If you want to add some variety to the event, find out what planets are in the sky during the event. For our spring 2008 events, we'll be featuring Saturn. There aren't any features to see on Saturn, but its moons are visible so you can prepare for those events by using the NASA simulator as previously noted, to show the arrangement of Saturn's moons.

If there is no planet to complement the moon in the sky, then double stars are a nice alternative. I don't have as much expertise in finding information about double stars, but Wayne Reed's website has a nice list of color-contrasted double stars. (The URL is awkwardly long. Just Google his name and "double stars".) Also I enjoy aa's articles in Sky & Telescope magazine about double stars.

Check out - and look at the articles "Pretty Double Stars for Everyone" and "More Pretty Double Stars". You should probably practice viewing the double stars that are interesting to you before the event. Make sure you can find them and make sure they look ok with your optics.

So with preparation complete you can pack up for the event. You can bring your red flashlight, but expect to use a standard white light flashlight when you need directed light. You can bring your green laser but don't be surprised if its beam is washed out. The more powerful lasers will be visible, but they won't be very dramatic.

Of course, you'll need other standard gear like your step stool for the little ones.

Published in the April 2008 issue of the NightTimes