Hack26.Sweep Constellations

Hack 26. Sweep Constellations

Stay focused on one or two constellations and bag everything they have to offer while you're in there.

Inexperienced observers often work one list exclusively during a session. For example, a beginner may decide to devote an observing session to bagging as many Messier Objects as possible. The problem with working that way is that you're all over the sky, working many different objects in many different constellations.

Experienced observers, in contrast, often "sweep" constellations, which is to say they devote an entire observing sessionor several sessionsto locating DSOs, multiple stars, and other objects in just one or two constellations. The advantage of working this way is that you become intimately familiar with the constellation, if only temporarily, and you are able to locate and observe more objects in less time.

The trick to constellation sweeping is to know which objects to look for in each constellation. The best way to do that is to develop your own customized list for each constellation, incorporating objects from whichever other lists you happen to be working on. As you develop your consolidated list, keep in mind your level of experience, your equipment, and your observing conditions. Many of the "advanced" lists, for example, contain objects that are difficult to find and may be invisible except with a large telescope from a very dark site.

A beginning observer might develop a consolidated list by constellation that includes objects from the following sources:

• Messier Club (http://www.astroleague.org)

• Binocular Messier Club (http://www.astroleague.org)

• Double Star Club (http://www.astroleague.org)

• Urban Observing Club (http://www.astroleague.org)

There is considerable overlap in these lists. For example, the open cluster M37 (NGC 2099) in Auriga appears on the lists for the Messier Club, the Binocular Messier Club, and the Urban Observing Club. Knowing that, you can observe M37 so as to get credit for multiple clubs. For example, if you observe M37 with your telescope from a dark site, you get credit only toward the Messier Club. If you observe M37 with your binocular from a dark site, you get credit toward the Messier Club and the Binocular Messier Club. But if you observe M37 with your binocular from your urban backyard, you get credit for all three clubs for that one observation.

Just because you can get credit for multiple lists doesn't mean that's the way you should do it. If you do it that way, you deprive yourself of some very nice views. M37 in a binocular from a bright urban backyard is a pathetic objectat most a faint nebulosity with a few stars. With a binocular from a dark site, M37 is an impressive open star cluster. With a telescope from a dark site, M37 is one of the jewels of the heavens, a scattering of bright diamonds on a pitch-black velvet field.

A consolidated list by constellation for an intermediate observer might add objects from the following sources:

• Deep-Sky Binocular Club (http://www.astroleague.org)

• Herschel 400 Club (http://www.astroleague.org)

• Caldwell Club (http://www.astroleague.org)

• Globular Cluster Club (http://www.astroleague.org)

• Royal Astronomical Society of Canada, Finest NGC List (http://www.rasc.ca)

• Saguaro Astronomy Club, 110 Best of the NGC (http://www.saguaroastro.org)

• Night Sky Observer's Guide (http://www.willbell.com)

Again, there is a great deal of overlap in these lists, but that's the reason for developing a consolidated list in the first place. Even if you observe all night long on every clear, dark night, it can take years to complete these lists. But there are other challenges awaiting you.

Advanced observers with large instruments and access to very dark observing sites don't need our help to develop consolidated lists, but as a starting point we recommend the Astronomical League lists for the Herschel II Club, ARP Peculiar Galaxy Club, and Galaxy Groups & Clusters Club. If you are looking for a lifelong challenge, consider a truly daunting project, such as observing the Herschel 2500 objects or all of the NGC and IC objects. That's the wonderful thing about amateur astronomyno matter how much you've accomplished, there's always plenty left to do.