- Exposure time: 1 panel of 220
minutes (11x
1200s) and 2 panels of 240 minutes (12x 1200s)
- Processing: Nebulosity 2.3 (pre-processing,
stacking & DDP); RegiStar
1.0 (combining); Adobe
Photoshop CS4 (post-processing)
- Lens/telescope: Takahashi FSQ-106ED (4.2")
quadruplet ED refractor at f/5 with
Baader
H-alpha 7 nm narrowband filter
- Camera: SBIG ST-8300M (T: -18
degrees Celsius)
- Mount: Astro-Physics Mach1 GTO
(guide rate: 1x, PEM activated)
- Guiding: TS OAG + SX Lodestar +
PHD (settings other than default: RA Aggressiveness 70; RA Hysteresis
20; Min. motion (pixels) 0.35)
- Location: Zoetermeer, The
Netherlands
- Date: May 14 - 15, 18 - 19 and 19
- 20, 2010
- Notes:
First light images with the
ST-8300M,
Lodestar guidecamera and OAG. The workflow for this mosaic was as
follows:
- Capturing light frames of
1200s
- Capturing a dark frame of 1200s
- Capturing a flat frame of 120s
with a home-made lightbox
- Capturing a dark frame for the
flat frame of 120s
- Capturing 30 bias frames in order
to create a master bias frame
Pre-processing
in
Nebulosity:
- Pre-processing flat frame with
master bias frame
- Creating a bad pixel map for the
flat frame with the 120s dark frame
- Substracting bad pixels from the
pre-processed flat frame
- Pre-processing light frames with
the
pre-processed, bad pixel subtracted flat frame and master bias frame
- Creating a bad pixel map for the
light frames using
the 1200s dark frame
- Subtracting bad pixels from
pre-processed light frames
- Equalising the histrograms of the
pre-processed, bad pixel subtracted light frames using the fifth light
frame of NGC 7000 as a reference
- Aligning (registering) the
equalised, pre-processed, bad pixels subtracted light frames and saving
each individual file
- Combining the individually saved
registered files applying a 1.75 standard deviation filter (sigma
stacking)
- Trimming the dark edges by making
a crop
- Applying the "Digital Development
Processing (DDP)" tool
Combining
in
RegiStar:
- Registering images
- Calibrating images
- Combining images (median / mean)
Post-processing
in
Photoshop:
- Adjusting levels and curves in
order to get a smooth and proper histrogram and as much dynamic range
as possible, without clipping
- Applying Noel Carboni's
Actions: Deep Space Noise Reduction; Local Contrast Enhancement
- Applying subtle unsharp masking
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