Observing Globular Clusters

Three to view if no others...

I’ve been doing a lot of reading and researching of Globular Clusters lately. I’ve also been observing them. I have been working on observing the Herschel 400 and am now just over a third of the way through that list. A few months ago, just before Rocky Mountain Star Stare 2000, my observing list had me observing some of the Globular Clusters of late Spring, in Boötes, Canes Venatici, Coma-Virgo, etc.

One in particular stood out to me, due to its proximity to M-3, the eighth brightest Messier Globular Cluster. You may know that M-3 is fairly large. So is the nearby NGC-5466 in Boötes. In fact, these two GCs share a nearly identical Declination, so with an Equatorial telescope (or maybe even easier without), you can easily swing back and forth between them in Right Ascension.

NGC-5466 is about the same size as M-3, but in my 10" LX5, it just appeared as a large round fuzzy patch of faint light. When I got the 12" LX200 in July, I pointed to 5466 and saw stars! This was soooo cool!

The latest cool Globular I’ve observed is NGC-288 in Sculptor in early morning skies right now. I’ve only seen it once, and the transparency wasn’t as good as it could have been, so I am not sure if NGC-288 is fainter than NGC-5466, but I am sure I was able to resolve stars in it, as well as see the faint background glow of the cluster overall. NGC-288 is huge.

It is at least the same size as M-13! About the time I observed NGC-5466 at Rocky Mountain Star Stare 2000, I began to realize that it should be possible to observe a lot of the Milky Way’s Globular Clusters. I wondered how many were "out there".

This latest experience has really ignited something in me. I’ve put together an Appendix to my observing web pages dedicated exclusively to Globular Clusters.

I have now observed 61 of the maximum 126 possible on my list of 152 Globular Clusters. I say maximum because I may have to revise my limiting magnitude range downward. Of course, there is always the 22" Cassegrain I now have access to.

Star Clusters, both Open and Globular, have always been my favorite Deep Sky objects - why I have had Schmidt-Cassegrain telescopes for twenty plus years now (OK, clusters and light-polluted back yards). Not long ago, Alan Baxter asked me about comments I have been making about Globular Clusters. He said something like, "I thought your favorites were Open Clusters?", perhaps feeling a little betrayed. They were, and now they are a very close second. Afterall, Open Clusters are visible all year round.

Globulars are too, but it is tougher. M-79 in Lepus, south of Orion is visible in the early mornings now, and NGC-2419, the most distant NGC "independent" Milky Way Globular is in Lynx just north of Gemini. Here, independent means not associated with a satellite galaxy of the Milky Way.

Because of the distance to NGC-2419, Astronomers once thought that it was not bound gravitationally to the Milky Way. They now know that Dark Matter associated with the Milky Way is what does keep it with us.

The Messier Globulars are bright and beautiful to behold. If you never plan to look at an NGC Globular, at least take a look at these three.

Adapted from a posting to Astronomy: General: 9 September 2000

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