Adam Block’s image of a small supernova remnant 3C 461 (Cassiopeia A) was beautiful but subtle in his exposure with the monster 24-inch Mt. Lemmon RCOS scope (link below). Seeing his image lured me in to try my hand at capturing “Cas A” from Chiefland, Florida at (essentially) sea level. Cas A is the brightest object in the sky (beyond the solar system) in radio frequencies and the Chandra orbiting telescope did some damage to it in x-ray wavelengths, but it is quite faint and small (7×7 arcmin) and private optically. It does not reveal its identity easily! It is apparently the youngest known remnant of a supernova explosion in the Milky Way!
Attached is my 20 hour LRGB exposure with the 14.5-inch RCOS using the Apogee U16M camera @ -30C robotically in November and December 2010. This is 10 hours luminance 1X1 and 10 hours total of red, green, and blue 2X2. This object is buried in the Chiefland light dome making it even more challenging! Some low humidity nights with good transparency helped the cause. A 40 minute long H-alpha exposure showed next to nothing; an equivalent OIII exposure would be interesting. Any takers???
http://www.caelumobservatory.com/obs/cassA.html – Adam Block image with 20-inch Kitt Peak RCOS
http://gallery.rcopticalsystems.com/gallery/cassiopeia_a.html — very best Cas A image – Adam Block image with 24-inch RCOS shown at Chiefland Star Party
http://chandra.harvard.edu/photo/2002/0237/ — x-ray Chandra image
http://coolcosmos.ipac.caltech.edu/cosmic_classroom/multiwavelength_astronomy/multiwavelength_museum/casA.html – Very COOL website!
http://hubblesite.org/gallery/wallpaper/pr2002015a/ – Hubble Cas A!
http://hyperphysics.phy-astr.gsu.edu/hbase/starlog/cassa.html – Spitzer Space Telescope image!!!