Cepheus Widefield in HO-LRGB (Jim Lindelien)

Cepheus Widefield in HO-LRGB

Swimming with the Shark in HO-LRGB

A wide and deep look at the dusty nebulae lurking under LDN1235 in Cepheus, including LDN1217.

Processing notes:

This camera's Bayer pattern is CFA[0-3]=RGGB. Of course there is a loss in quantum efficiency in double-filtering narrowband signals thru a Bayer filter.

Overall this is a dim field of view and presents a challenge. Although there is not too much OIII, there's certainly some but it's very dim. To reach a deeper narrowband OIII stack and improve its SNR I employ a sort of hybrid binning strategy akin to the old established method of binning 1x1 for L and 2x2 for color filters in the old days of noisier mono CCD sensors.

Furthermore, Bayer matrixing is, itself, another form of hybrid binning.

Bayer CFA0 subarrays (red pixels) from Duo and Ha filters combined into a single Ha master stack of 39x300s then 2x drizzled back to native camera resolution.

Bayer CFA1, 2 and 3 subarrays (greens and blue pixels) from Duo and OIII filters combined into a single OIII master stack of 213x300s then 2x drizzled back to native camera resolution.

In other words, although the "wallclock" time on the sky was about 11.75 hours total, the OIII stack is almost 18hrs deep, the Ha 3.25 hrs; and the RGBs, about 4.25hrs.

OSC 15s and 30s L filter subs combined into one master stack for unsaturated stars post processing.

OSC 120s and 300s L filter subs combined into one master stack for background (starless dust and nebulae) post processing.

An additional master luminance layer was created by combining all filter data.

There is no such thing as a free lunch, so here I trade resolution for stack depth and noise control. That said, neither the narrowband objects nor the dusty structures change much in intensity from one pixel to its neighbors, so the hybrid binning is not visually noticeable in the final result.

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CMOS Imagers
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The OSC Club (One Shot Camera)
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Status	Advanced success
Started	...
Astrometry.net job	8298498
PixInsight job	HD1V6LENX1OXJ533H3LLC7SP9LMOCNPQ
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	22h09m51s.44
RA (top/left)	22h26m13s.81
RA (top/right)	21h33m42s.32
RA (bottom/right)	21h58m13s.93
RA (bottom/left)	22h38m20s.48

Dec (center)	+71°18′05″.2
Dec (top/left)	+74°33′20″.8
Dec (top/right)	+73°26′09″.8
Dec (bottom/right)	+67°59′03″.3
Dec (bottom/left)	+68°49′22″.5

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