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M77 Galaxy (Spiral Galaxy)
Nick Keeley

Previous imageUp to Astr110 IndexNext imageSpiral Galaxy

As seen above, the image displayed is a spiral galaxy, specifically M77.  Spiral galaxies generally appear like flattened white disks with yellow-like bulges at the center (Bennett 607).  Making up 7% of all galaxy types, spiral galaxies have a range of large-to-small sized bulges, are surrounded by countless amounts of stars, and often have long spiral arms.  Inversely related to the size of a bulge, a galaxy's spiral arms are more clumpy with a smaller sized bulge.  An example of a spiral galaxy is our own Milky Way galaxy.  M77’s distance is 60 million light years (Frommert and Kronberg).  M77 is found in the constellation Cetus A and was discovered in 1780 (Frommert and Kronberg).  Originally misclassified as a nebula by its founder, Pierre Mechain, and subsequently as a cluster by Charles Messier, M77 is one of the biggest galaxies on record, as well as one of the first spiral galaxies to be recognized (Frommert and Kronberg). 

As seen by the image above, the spiral galaxy M77 can be classified as a Sb spiral.  This means that it has a medium-sized bulge and features spiral arms that are somewhat clumpy and broad structured. The spiral arms are very noticeable, and appear to feature clouds of dust interspersed with younger blue stars.  The image has clumps of blue all around the spiral galaxy.  The colors of the stars vary from blue, the warmest and youngest, to yellow to red, which is the coolest and oldest. The linear size of M77 is approximately 70,000 light years.

Bennett, Jeffrey, Megan Donahue, Nicholas Schneider, and Mark Voit. The Cosmic Perspective. 6th ed. San Francisco: Addison-Wesley, 2010. 607-08.

Frommert, Hartmut, and Christine Kronberg. "Messier 77." Students for the Exploration and Development of Space. Accessed 3 Dec. 2010.<>.

Right Ascension (J2000) 02:42:40.25
Declination (J2000) -00:00:48
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 300 seconds BVRC
Date observed

October 26, 2010 (CBVR)



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