Seagull Nebula and Thor's Helmet at 85mm in HOO (JDJ)

Seagull Nebula and Thor's Helmet at 85mm in HOO

This wide field image of the region around the Seagull Nebula (IC2177) was captured on the night of February 8, 2020 using a short telephoto lens and dual narrowband filter. The field of view also includes Thor's Helmet. This session was a bit of an experiment. I've been capturing DSO target subs with this lens/filter combo at ISO 200 x 240 s exposure, but I wanted to see how a stack of shorter subs at higher ISO would turn out so I shot these at ISO 800 x 60 s. The results were nowhere near as good as the longer exposures (no surprise). There is a weird streaking image artifact in these shots I can't figure out and of course the noise is worse. Still glad I gave it a go, particularly since I can only image the Seagull Nebula region for 1 hour per night due to obstructions.

Imaged with 85mm/F1.4 Rokinon at F/2, STC Duo Narrowband Clip Filter, and full spectrum modified Nikon D5300.

Total integration time was ~1 hours using 70 subs at ISO 800 x 60 sec. Pre-processed using PixInsight Batch Pre-Processing (BPP) script. Images calibrated using darks, bias, and flats. Instead of separating out the R, G, and B channels and processing the narrowband results separately, I just processed this as a standard RGB image (one of the benefits of using a dual narrowband filter with a OSC DSLR). Post-processed in PixInsight: Cropped, gradient removal with ABE, MLT for noise reduction, stretched in two stages, stage 1 stretch using histogram transformation with starmask generaated using starnet++ (to start to bring out the nebulocity), stage 2 stretch using masked stretch, Curves Transformation, TGVDenoise for noise reduction, HDR transform, Local histogram transform, morphological transform to shrink stars.

Cloudy Nights
DSLR narrowband
Suburban Astrophotography
The OSC Club (One Shot Camera)
Camera Lens Astrophotography

85mm Rokinon

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Status	Advanced success
Started	...
Astrometry.net job	3317073
PixInsight job	TO68NGEZSFH92SNQM36F2CM8L04NVUI3
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	07h09m28s.26
RA (top/left)	06h54m18s.82
RA (top/right)	06h55m56s.32
RA (bottom/right)	07h24m59s.99
RA (bottom/left)	07h22m37s.19

Dec (center)	-11°04′04″.1
Dec (top/left)	-07°10′40″.5
Dec (top/right)	-15°20′18″.8
Dec (bottom/right)	-14°54′07″.1
Dec (bottom/left)	-06°45′52″.8

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