Waid Observatory

Object: Sh2-171 - NGC7822
Date: Sept. 20-21 - Oct. 01, 2017   -   Location: Davis Mountains, TX
Telescope: Stellarvue SV-102 ED  Mount: MI-250   Camera: ST-8300M
Exposure: SII, Ha, and OIII = 260 min. each (20 min. sub-exposures)

Click on the image below to view at higher resolution.


Sh2-171 - NGC 78221

Sh2-171, as designated in the Sharpless Catalog of HII emission nebulae, is a star forming complex located in the constellation Cepheus at an approximate distance of 3,000 light years from the Earth.  A very young cluster of stars, designated Berkeley 59, is located in the upper center right of the image.  The cluster is only a few million years old and is the primary ionizing source of illumination for the nebula.  Its intense radiation and strong stellar winds have shaped and eroded the many columns and pillars seen in this remarkable star forming complex.  The Berkeley 59 cluster contains one of the hottest stars within a thousand parsecs of the Sun.  It is an eclipsing binary containing an O5V star (BD+66 1673) with a surface temperature of almost 45,000 Kelvin.  It has luminosity approximately 100 thousand times that of our Sun.  2The bright star located in the center of the image (SAO 10956) is not associated with Sh2-171.  It is a foreground star approximately 317 light years from the Earth.

The image above is known as a mapped, or false, color image and was acquired using narrowband filters.  It was assembled using the standard Hubble Palette with SII mapped to red, Ha mapped to green and OIII mapped to blue.  A Bi-Color (near true color) version of the image may be viewed here.

2Software Bisque - TheSkyX Professional Edition

Copyright Donald P. Waid