- Exposure time: 180
minutes (20 minute sub-exposures)
- Lens/telescope: INTES 150 mm (6")
MK-69 Maksutov-Cassegrain at f/6
- Image scale: 1.24 arcseconds per
pixel, FOV 68.5' x 51.6' (F = 900 mm at 5.4 micron pixels)
- Camera: SBIG ST-8300M (T: -25 degrees
Celsius) with Baader
H-alpha 7 nm narrowband filter
- Mount: Astro-Physics Mach1 GTO
(guide rate: 1x, PEM activated)
- Guiding: TS OAG + SX Lodestar +
PHD
- SQM: 21.0 (28% moon, magn. -8.8)
- Location: Etoile St. Cyrice, Hautes-Alpes,
France
- Date: March 10
- 11, 2011
Workflow
Image acquisition:
- Capturing 1 flat frame of 60s
with a Geoptik Flat Field Generator
- Capturing 9 light frames of
1200s
- Capturing 3 dark frames of 1200s
Pre-processing
in
Nebulosity
(v2.3.5):
- Pre-processing the flat frame
with a
master bias frame
- Pre-processing the light frames
with
the
pre-processed flat frame and a master bias frame
- Stacking the dark frames applying a 0.75
Standard Deviation Filter (sigma
stacking)
- Creating a bad pixel map of the
stacked dark frames
- Subtracting the bad pixels from
the pre-processed light frames with the bad pixel map
- Aligning (registering) the
pre-processed, bad pixels subtracted light frames and saving
each individual file
- Stacking the individually saved
registered files applying a 1.25 Standard Deviation Filter (sigma
stacking)
- Trimming the dark edges by making
a crop
- Applying the "Digital Development
Processing (DDP)" tool (adjusting Xover)
Post-processing
in
Photoshop
(CS4):
- Adjusting levels and curves in
order to get a smooth and proper histogram and as much dynamic range
as possible without clipping
- Applying the "PictureCode Noise
Ninja" noise reduction tool
Finishing
touches
in
Nebulosity
(v2.3.5):
- Sharpening image with "Tighten
Star Edges"
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