Observation Log - May 3, 2000 - Greenwood, NJ

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Well, this night at Greenwood was an extraordinary event. Dan's and David's twin 18" light buckets provided an outstanding view of a bunch of galaxies. The highlight of the night for David Segelstein was his observation of Abell 1656, a galaxy cluster in Coma Berenices. The cluster is a BIG batch of LITTLE galaxies, ranging from about mag 11.5 down to the limit of visibility. The light from these galaxies started out on its journey to earth about 425,000,000 years ago! David had a finder chart which he had generated from SkyMap Pro 6. For about an hour, we all heard his voice from up on the ladder, "There's 4889! And there's 4886!" This went on and on until he had pretty much depleted the list of observable galaxies!

Before David started his observations, we talked about taking a CCD image of the area (or PART of the area), so I went to work. I centered my lowly 10" f6.3 LX200 on the cluster, specifically to 13 00.0 RA, 28 00 DEC (talk about easy to remember!) and cut loose a series of exposures. I ended up with 17 frames for a total of 33 minutes of photon collecting. At that time, my SCT dewed up ON THE INSIDE and business came to an end. And here is the result: Abell 1656! This photo has an extreme contrast stretch designed to bring out the faintest of the galaxies. It's not as "pretty" as it might be, but our goal was to image the little dim ones!

And to help you with identification of all those little island universes, here's a finder chart from SkyMap Pro 6. A couple of notes: The map shows dimmer galaxies than stars. I set the limit for both at mag 20, but the stars come from the Hubble Guide Star Catalog, which isn't exactly a complete set. So you may see stars on the image that are not on the finder which are brighter than galaxies that ARE on the finder chart. Confusing, I know, but you have to live with what you've got! And now for the good news. The limiting magnitude of the image seems to be about magnitude 19. The little galaxy 126759 is listed as 18.2, and that's an easy one to identify. Number 126765 is listed as mag 19.2, and if you really look hard and MAYBE use your imagination a bit, it's there! A couple of other faint galaxies are 44635 at mag 17.9 and 126781 at mag 18.4. I believe that at least 40 of the galaxies on the finder chart are visible on the image. [BTW, if you are using SkyMap Pro 6, center your display at the coordinates above, boost the magnitude limits to 20, and you'll have to rotate the field to the right a ways to match the view in the image.]