Cassiopeia A or Cas A (October 8, 2013)

Cas A is a supernova remnant very near the Bubble Nebula (NGC 7635) and M52 in Cassiopeia.  Astronomers estimate that Cas A blew up around 300 years ago.  There is no certain historical record of the event, though one celestial cartographer recorded a star near this location that does not appear there now.

I have always wanted to see this object, and I was encouraged by Sue French's column in the November 2013 Sky & Telescope.  Ms. French said the remnant was visible in her 10-inch scope, so I thought it would be visible with my refractor and camera.  And here it is.  I was unable to find many amateur images of Cas A, but Ken Crawford's is spectacular.  The Chandra X-ray Observatory also has great material on Cas A, including a movie showing the movement of material in the nebula over a relatively few years.  The movie appears to show a central star that may be the neutron star left after the explosion.

This is not a pretty picture, just an observation.  I took only a few hours through a narrowband OIII filter, and the object is very dim.  I had to take an exposure of a few minutes just to find it.  But it's exciting to look at such an object and imagine the tremendous forces that created it and continue to operate there.  The remnant is roughly 11,000 light years away.

Telescope: Astro-Tech AT111EDT and William Optics AFR-IV (eff. at f/5.6)
Camera and Exposure: SXVF-H9 (OIII: 8x600"), Alnitak Flat-man flats
Filter: Astronomik OIII
Guiding: SX Lodestar and SX OAG
Mount: Takahashi NJP
Software: Nebulosity, Maxim DL, Photoshop CS3
Location: The Woodlands, TX