NGC 1023 - Arp 135

Object: NGC 1023 galaxy in Perseus 9.5m, 7.4'x2.5' type SB0 (sometimes referred to as lenticular), distance 32 Mly. This galaxy is thought to contain a supermassive blackhole in the core and is believed to be interacting with the irregular dwarf companion NGC 1023A. It also has an extremely bright globular cluster orbiting it, Mv = -10.9, the same brightness as Omega Centauri near our Milky Way and G1 in M31.

Subimages: 13 x 300s (~1 hr) SD Mask combined after bias, dark and flat calibration. Output ~3.5"
Scope: C11XLT with C6.3FR, EFL=1590mm (f/5.7 effective)
Mount: Losmandy G11 with Gemini L4
Camera: ST7EI (1.17"/pixel) set to -25C oriented at 5d21' (N up, E left)
Guiding: SX716 camera on a Taurus Tracker III OAG. Exposure time 1 sec, forgot to dither guider!
Acquisition and Processing: MaxIm DL/CCD v4.5
Imaged on: Nov 25, 2006

Processing:

Combine: SD Mask, Frame Align=Auto Correlation, Bilinear resampling.
Filter: Kernel Hot Pixel remove, 2% threshold. I don't normally have to do this but since I forgot to dither the guider....
Remove Bloom: Three brightest stars, used very large boxes for the brightest two.
Clone: corners of repaired bloomed stars using the Kernel filtered image as the source.
DDP: bgd=990, mid=1300, filter=none.
Clone: Again, to fix bloom fix remnants exposed by aggressive DDP. Used offset regions from a duplicate image.
Edit Pixels: Final clean up of remnants and of two leftover hot pixels near bright stars.

Colorized version

Color stack command putting mono into R, G and B channels then Levels command with:

	Black	Gamma	White
R	0	1.2	249
G	0	1.4	256
B	9	0.8	256