As a beginner in astronomy, I was taken aback by all the catalogs I came across. It turns out that just about everything you can see in the sky is in some catalog.
There’s even a catalog of catalogs, and one object can appear in multiple catalogs!
The most well-known catalogs are the Messier and NGC. The Messier catalog is made up of over 100 objects that are not particularly related. Charles Messier, the man who published the final version of the catalog in 1781, was simply looking for comets and cataloged objects he often came across that were not comets. But the catalog survives to this day and encompasses some very interesting objects.
The NGC, which expands to the New General Catalog of Nebulae and Clusters of Stars, hosts some 7,840 objects made up of galaxies, globular clusters, planetary nebulae, and others.
So the question for a a beginner astronomer is, if everything I can see is in a catalog, is there anything new to discover?
The answer to that question is a resounding Yes! And even beginning astronomers can make important discoveries!
A catalog is just the result of a survey of the sky – a catalog records the positions of objects of interest and nothing more. Some catalogs relate things of interest – like the Hickson Compact Group catalog which lists over 100 groupings of galaxies that meet specific criteria. Others, like the Messier catalog, are just a grouping of objects.
Just because we have seen something in the sky doesn’t mean that we know everything about it. For example the Fireworks Galaxy, also called NGC 6496, was discovered by William Herschel in 1798 and it resides in the NGC. However, just because we have cataloged it does not mean it’s the end of the story as far as discovery goes.
The Fireworks Galaxy got its name from being such an active galaxy. During the past 100 years that one galaxy has been home to 10 supernovae, which is an impressively large number of supernovae events.
More recently, in January 2019, a very bright supernova was discovered in NGC 3254. NGC 3254 was cataloged by William Herschel in 1785 yet we’re still making discoveries about it today!
Also in February 2019, a supernova called AT2019abn was discovered in M51 – a Messier object! Messier objects are very popular and studied by many, yet someone found a brand new supernova in it just this month! It was even observed by a Slooh.com member – view the observation here.
Catalogs are the guideposts that lead your journey through the skies. I recently completed imaging all of the members of the Hickson Compact Group (HCG) Catalog. It took me a couple of years but it was an interesting process locating each of these objects and imaging them. I also learned a lot about the Slooh.com telescopes and enjoyed sharing my findings.
I encourage you to look through the various catalogs that are available. To get you started, here’s a link to a page lists all of the objects in the NGC, IC, and PGC catalogs with photos: https://cseligman.com/text/atlas/ngc00.htm
If you’re just getting started in astronomy and are thinking of buying a telescope, consider this blog post.
I also encourage you to take a look at my book written for beginning astronomers, Remote Astrophotography Using Slooh.com – A Handbook.
You can view the first 10% of the book on Amazon.com, where you’ll be able to browse through the table of contents and browse through the first chapter. I have also made part of the book available for download on this website.