Tuesday, September 17, 2013

Pacman Nebula Ha

Pacman Nebula Ha by S Migol
Pacman Nebula Ha, a photo by S Migol on Flickr.
Via Flickr:
Pacman Nebula in Ha as seen on the evening of Sept 15, 2013. The moon was after first quarter, so the sky was pretty bright. Shot with a Baader Ha filter - 35 nm wide so it's not very tight and allows a lot of extra light through.

This is a stack of 6 1200 second exposures at 100 ISO with the converted and cooled Pentax K10D camera shot through the Stellarvue SV4 scope.

Calibrated with Maxim using my standard process. I'd tried calibrating with just the red channel but didn't like how the noise was so prevalant. Plus the reduced size seemed to lose a lot of detail in the stack.

Processed in PI pretty simply: crop, masked stretch, histogram stretch, and masked curves. Didn't need to do anything else.

I'm rather pleased with the outcome.

Here's the platesolve:
=============================================================
Referentiation Matrix (Gnomonic projection = Matrix * Coords[x,y]):
-1.0234e-005 +0.000530248 -0.662942
-0.000530054 -1.02716e-005 +1.03623
+0 +0 +1
Projection origin.. [1930.000003 1287.499936]pix -> [RA:+00 51 46.25 Dec:+56 44 54.92]
Resolution ........ 1.909 arcsec/pix
Rotation .......... -88.903 deg
Focal ............. 648.33 mm
Pixel size ........ 6.00 um
Field of view ..... 2d 2' 48.4" x 1d 21' 55.4"
Image center ...... RA: 00 51 46.249 Dec: +56 44 54.92
Image bounds:
top-left ....... RA: 00 46 47.891 Dec: +57 46 43.03
top-right ...... RA: 00 46 46.880 Dec: +55 43 57.34
bottom-left .... RA: 00 57 02.150 Dec: +57 45 05.18
bottom-right ... RA: 00 56 28.593 Dec: +55 42 24.66
==============================================================