Waid Observatory

Object: Sh2-176
Sept. 22/23/24, 2022    -    Location: Davis Mountains west of Fort Davis, TX
Telescope: 10 in. RC   Mount: Paramount MX   Camera: Apogee Alta F8300M
Exposure: Ha = 18x30 min. Bin 1x1   R G & B = 15x15 min. each Bin 2x2
Click on the image below to view at higher resolution.



Sh2-176 - Planetary Nebula in Cassiopeia

Sh2-176, as listed in the Sharpless Catalog, is located in the constellation Cassiopeia 140 parsecs(2) (457 light years) distance.  Sabbadin et al 1977(2) determined Sh2-176 to be an ancient planetary nebula that is expanding at a rate of 19 kilometers per second(1).  Sh2-176 is very faint and has expanded to a diameter of about 1.6 light years(3).  Although the nebula is essentially round, it is asymmetrically brighter toward the southeast.  This is probably due to a bow shock produced by interactions with surrounding interstellar medium(1).  This bow shock displays as a bright crescent in the lower left section of the nebula.  The central star is a dim blue subdwarf with a magnitude of 18.74(1).

1Anthony Ayiomamiti: - http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176.htm
2Sabbadin, F. et al 1977 - https://articles.adsabs.harvard.edu/pdf/1977A%26A....60..147S
3Stellar Scenes - https://stellarscenes.net/object_e/sh2_176.htm

Copyright Donald P. Waid