NGC 7479

Object

NGC 7479 is a barred spiral galaxy of 11th magnitude in the constellation of Pegasus. The galaxy has a very asymmetric spiral structure. The most dominant features are the bright, long bar and the luminous western spiral arm.

Equipment

Telescope: 12" F5.3 Newton
Mount: EQ6 Skyscan
Camera: SBIG ST7e ABG
Filters: SAC-filterwheel with Astronomik LRGB filters

Circumstances

Date: 31 august 2005/ 2 september 2005 / 7 september 2005
Location: Steenbrugge
Weather: Clear sky, 14°C
Temperature CCD: -14°C; -17°C; -21°C

Technique

Technique: LRGB-technique
Exposure: LRGB 180:118:118:186
Processing:
Exposures:
31aug: l-data: 5minx36 (-14°C) 180min
2sept: r-data: 59x2min (-22°C) 118min
7sept: g-data: 59x2min (-17°C) 118min
7sept: b-data: 93x2min (-17°C) 186min
Flat, dark bias automatic subtraction:
Aligned en add-combined in ccdsoft
Deconvolution of 2 iterations in CCDsharp
Gamma stretch in MaximDL for luminance
Several DDP's of luminance and layered in photoshop to become the final luminance data
RGB-dataColor combined in CCDSoft
Luminance layering in Photoshop 6.0
Levels, blur and Unsharp mask in Photoshop
Small noise reduction in NeatImage

Comments

I tried to do a mega-exposure with 10 hours of total exposure time. If I wanted to reach this, I had to spread the exposure time over several nights. I had some failures due to incoming clouds, finding the object and a lot of human errors (bad darks). The final result satisfies me a lot !