tornado33
12-02-2013, 10:46 PM
Hi all
Finally got to do some DSO imaging after too long a break, and under dark skies too, visiting an Aunt in Gloucester, took up my 6 inch F3.6 Cometracker SN.
Here is M42, 9x 10 mins ISO 200. No filters at all so full spectrum including near IR. Yet subs showed almost dark sky background, whereas in Newcastle they would be almost white. Thermal noise was more evident than any sky glow. Took a few 30 sec subs to mask in the bright core. Used Berts Parracor coma corrector, it increases the focal length a bit and gives a flatter field with the Cometracker then the MPCC I normally use.
Larger version here (http://d1355990.i49.quadrahosting.com.au/Scott/m42x9x10minsiso200unf6inchmod350dgl oucesterwarmp_filteredl.jpg)
Sadly the inexpensive Cometracker has an uncoated corrector plate, susceptable to internal reflections from bright stars. One is in the Running man Neb top right. Still, happy to get the brown dust around the bright nebulae.
Scott
Finally got to do some DSO imaging after too long a break, and under dark skies too, visiting an Aunt in Gloucester, took up my 6 inch F3.6 Cometracker SN.
Here is M42, 9x 10 mins ISO 200. No filters at all so full spectrum including near IR. Yet subs showed almost dark sky background, whereas in Newcastle they would be almost white. Thermal noise was more evident than any sky glow. Took a few 30 sec subs to mask in the bright core. Used Berts Parracor coma corrector, it increases the focal length a bit and gives a flatter field with the Cometracker then the MPCC I normally use.
Larger version here (http://d1355990.i49.quadrahosting.com.au/Scott/m42x9x10minsiso200unf6inchmod350dgl oucesterwarmp_filteredl.jpg)
Sadly the inexpensive Cometracker has an uncoated corrector plate, susceptable to internal reflections from bright stars. One is in the Running man Neb top right. Still, happy to get the brown dust around the bright nebulae.
Scott