NGC 2685 – Galaxy In Ursa Major – March 2021- Observer’s Challenge Report # 146

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

March 2021

Report #146

NGC 2685, Galaxy In Ursa Major

Sharing Observations and Bringing Amateur Astronomers Together

march-2021-observers-challenge-_ngc-2685-2

Introduction

This month’s target

German astronomer Wilhelm Tempel discovered NGC 2685 in 1882 with an 11-inch refractor. Loosely translated, his discovery description reads: Good II-III; round; with a small star in the middle; stands 4′ south of a 10th-magnitude star. 

In the Hubble Atlas of the Galaxies, Allan Sandage states, “NGC 2685 is perhaps the most unusual galaxy in the Shapley-Ames catalogue.” While most astronomers would agree with this, there remain various opinions as to why. NGC 2685 is generally regarded as a polar ring galaxy wrapped in exterior hoops of gas and dust aligned nearly perpendicular to the plane of the galaxy’s lenticular disk. The rings may have been birthed by a merger and/or accretion event. A less touted viewpoint is that this galaxy is strongly warped, and the semblance of rings is merely the result of projection effects.

This perplexing galaxy lies roughly 50 million light-years away from us. As seen photographically, the unusual array of gas, dust, and resultant stars entwining the Helix gives rise to its name. The galaxy may also house a supermassive black hole. Sue French

Date: February 3, 2021

Telescope: 10-inch reflector

Sketch Magnification: 114x

Field of View: 1/2º

Description: Small, fairly bright, elongated NE-SW, brighter bulged center with a stellar nucleus. I last observed this galaxy on March 11, 1996, from the same location and telescope with almost identical results.

From my 5.0 NELM suburban location, it is very easy to locate and see with the 10-inch, but with very little fine detail. The stellar nucleus required a magnification of 183x, and averted vision. It was my plan to observe this galaxy with my 6-inch reflector for a comparison. Hopefully, I can make this comparison next year. Roger Ivester

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