Roaming the Deep Sky #9
NGC7619 and NGC7626
By Don Clouse
NGC7619 and NGC7627 are two very similar appearing elliptical galaxies in Pegasus visible in the same field of view. I observed this pair of galaxies for the first and only time (so far), shortly after 8pm (CST) on October 28 at Twin Lakes Star Party 2000. The sky conditions that evening were among the very best that I’ve experienced in my three years of observing – so I figured I had to write this article about one of the sixteen observations I recorded that evening. This close pair seemed an interesting choice for several reasons.
I find that I really enjoy multi-galaxy fields of view. There are several suitable even for smaller scopes. I suspect that this pair, however, will require at least 6" of aperture. Both galaxies are listed1,2 as having a magnitude of 11.1. These observations were done with my 8" SCT and a 20mm eyepiece. This particular combination yields a magnification of 102x and a 31’ field of view, easily encompassing both galaxies. Here’s what I wrote about NGC7619, "Circular, perhaps 2’ in diameter. Non-stellar core with much dimmer, surrounding haze." And for NGC7626, "Visible in same field with 7619 and separated from it by 9’. Core is less distinct than 7619. Slightly larger than 7619, perhaps 2.5’x2. 5’." When I write these articles, I like to check my observations against the experts.1,2,3,4 For instance, the separation between the two is only 7’, not 9’, but hey, I was close. (Normally, I only read the descriptions after the fact, as I don’t like to prejudice my observation.) The sources were in agreement on 7626’s core being less prominent than 7619’s. However, contrary to my perception, all describe 7619 as being the larger – up to 2.9’ in diameter with 7626 being from 2.0’ to 2.4’ in diameter.
The first chart5 can be used to locate these galaxies on the sky about 2.5 degrees northwest of the top of the Pisces Circlet asterism and around seven degrees south of the west side of the Great Square of Pegasus. This chart shows stars to 9th magnitude. The second chart is a bonus for those with 12" or larger telescopes. It shows stars and galaxies to 15th magnitude. NGC7619 and NGC7626 are the dominant members of the Pegasus I Galaxy Group. The cluster’s distance is given variously as 160 million light years2 (mly) and 250 mly1. One source3 remarks that 10 to 12 galaxies can be seen within a one-degree area. That sounds like something worth checking out with a big scope.
Sources:
- The Night Sky Observer’s Guide, George Kepple and Glen W. Sanner, Willmann-Bell, Inc., 1998.
- SkyAtlas 2000.0 Companion, 2nd edition, Robert A. Strong and Roger W. Sinnott, Sky Publishing Corporation, 2000.
- Observe the Herschel II Objects, Candace Pratt and Carol Cole, Rose City Astronomers, the Astronomical League, 1997
- Observing Handbook and Catalogue of Deep-Sky Objects, Christian B. Luginbuhl and Brian A. Skiff, Cambridge University Press, 1990
- MegaStar 4.0, E.L.B. Software, Willmann-Bell, Inc., 1997.
Visitors of This Page Since 3/31/02
