Archive for September 10, 2018

09/10/2018 -Ephemeris – The Coathanger in the sky

September 10, 2018 Comments off

Ephemeris for Monday, September 10th. The Sun will rise at 7:15. It’ll be up for 12 hours and 47 minutes, setting at 8:02. The Moon, 1 day past new, will set at 8:57 this evening.

Just about every amateur astronomer knows a little asterism or informal constellation called the Coathanger. It’s stars are mostly below naked eye visibility, but it is a great sight in binoculars. It’s located along a line from Altair in Aquila the eagle to Vega in Lyra the harp. These are two star of the Summer Triangle. It is also just west of, or right of, the constellation Sagitta the arrow. It consists of six stars in just about a perfectly straight line with four stars in a tight group south of them making the hook. In telescope finders which invert the image the Coathanger appears right-side-up. Arab astronomer Al Sufi discovered it and described it in 964 AD. It has the catalog designation of Collinder 399. It is also known as Brocchi’s Cluster.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Coathanger finder animation

How to find the Coathanger. Look for the Summer Triangle. On the line from Altair to Vega the Coathanger can be found. Star imaged by Bob Moler.

Binocular view of the Coathanger

Binocular view of the Coathanger. From the original resolution of the above photograph.

Telescope finder view of the Coathanger

Telescope finder view of the Coathanger. Telescope finders usually invert the image, so it looks like a proper coat hanger.