Beyond the Messier and NGC\IC
By Shawn Grant
You ask most amateur astronomers what catalogs of deep sky objects there are that are not part of the Messier and NGC/IC catalogs. Most will answer there are a few but they are dim, uninteresting and only for the pros. That is a popular myth and I will set it straight and lead you to ways to go beyond the Messier and NGC/IC trap.
There are no dark nebulas included in the Messier and NGC/IC catalogs. A dark nebula is gas and dust that block the light of stars or bright nebula behind them. They are seen as a dark patch against a star background or nebula. The most popular dark nebula catalogs are the famous Bernard catalog and the much larger LDN catalog. Dark nebulas do not have a magnitude rating instead they are rated by how opaque they are. The more opaque the easier they are to see. The LDN catalog rates the opaqueness from 1-6 with 6 being the most opaque. Some are quite large, opaque and can easily be seen with the naked eye such as the great rift that runs through Cygnus, the Coal stack and the Pipe Nebula. There are several visible with binoculars enough to keep one busy for a life time. The telescope opens a whole new world of dark nebula. There are few thousand visible in amateur telescopes.
There are several open cluster catalogs outside the Messier NGC/IC catalogs. Some of these catalogs are Basel, Berkeley, Collinder, Czernik, Dolidze, King, Melotte, Stock and many others. There are several of these clusters that are bright enough to be seen with the naked eye. Melotte 111 is a prominent cluster in Coma Berenices. There are hundreds that can be seen in binoculars. In fact the AL binocular deep sky certificate includes many open clusters outside the M/NGC/IC catalogs. Some of my favorite binocular open clusters are Stock 2 the strong man cluster and Collinder 399 the coathanger. There are over a thousand visible in telescopes 12” or smaller enough to keep busy for a lifetime.
There are many planetary nebulas outside the M/NGC/IC catalogs. There are several hundred planetary nebulas in the PK and Abell catalogs. Most of these are faint but are fun challenges for large telescope owners and ccd imagers, however there are several that are bright enough to be seen in 12” or less scopes. A great book on planetary nebula is “Planetary Nebula A Practical Guide and Handbook for Amateur Astronomers” by Steven J. Hynes from Willmann-Bell, Inc.
There are many thousand nebulas in catalogs such as Sharpless, Lynd’s Bright Nebula, Van Den Bergh and a few others. Most nebula are not visible in amateur telescopes but some are. Some are nebula outside our galaxy and in other galaxies. M33 and M101 have nebulas within them that are visible through amateur telescopes. These can be enhanced with a broadband nebula filter.
There are a few globular cluster catalogs other then M/NGC/IC. A popular challenge for large telescope owners is to try to see all 15 of the globular clusters from the Palomar catalog. Another catalog is the Terzan which has 11 globular clusters. There are globular clusters that orbit the Andromeda Galaxy which a few can be visually seen with 12” scopes and larger and even more can be imaged. They don’t look like globular clusters but like stars so they will be hard to identify. One way to do it is compare the image with what Guide plots.
Galaxies are probably the most numerous of deep sky objects. The PGC catalog currently contains a million galaxies. There is also the Uppsala, MCG, CGCG, Markarian, Hickson and Arp which Sparky is very familiar with. Many of the catalogs contain NGC/IC objects but many more are outside that catalog. Many of the galaxies can be seen in larger amateur telescopes but most are of interest to CCD imagers.
There are several references that gives you information and helps you locate the objects in the catalogs mentioned in this article. Uranometria and the new millennium star charts plot many of these objects. A great book with visual descriptions is “The Night Sky Observer’s Guide” by George Robert Kepple and Glen W. Sanner. The best reference for catalogs outside M/NGC/IC list is computer software. Guide, DeepSky 2003, SkyTools version 2, SkyMap Pro and Cartes Du Ceil plot objects in all of the catalogs featured in this article.
Have fun and go beyond the M/NGC/IC trap.
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