IC 405: The Active Region (Alex Woronow)

IC 405: The Active Region

IC 405: The Active Region

OTA: AG10
Camera: Proline 6303
Observatory: Insight Observatory (AFIL-1)

Exposures:
H: 25 x 900 sec
O: 32 x 900
S: 40 x 900
Total Exposure time used: 24.25 hours
Image Width: 37 arc minutes (cropped by almost half in width)

Processing: PixInsight, Topaz Studio2, custom scripts for image weighting and star replacement

I want to thank Mike Petrasko of Insight Observatory for accommodating my picky questions about the data. Great customer service! Great data set!

This narrowband image has been mapped to "true color." That is, SII is set to pure red, Ha is set to red with about 10% green—because it lies greenward from SII—and OIII is set to a teal color. That scheme works fine for the nebula, but it is impossible to fully accommodate the color range of the stars. The color space is limited by the vertices of red and the blue and green limits as set by the teal OIII line. All processing I do is in sRGB. I understand that broader color spaces are possible on my screen, but ultimately, for publication or printing, one needs to provide an sRBG image and processing in, say, Adobe RGB, and converting to sRGB in the end alters the color distribution in the image, possible adversely affecting the color detail.

Simultaneously, color calibration of the stars pushes the hydrogen areas toward an orange. Apparently, you cannot have both true nebula colors and approximately correct star colors.

This data set is large, probably overly large, for any reasonable sky limit to image resolution and noise abatement. AI noise reduction drove the remaining noise lower, indicating that it could have done the same with a greater noise level from far fewer subframes. However, there the subs were, so I used them.

One pixel on this image subtends 1500 giga-kilometers on the nebula…so the minimum-size structures seen in this image are hardly small!

Alex Woronow

	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

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Status	Advanced success
Started	...
Astrometry.net job	8158372
PixInsight job	AZU1WS2N7DSG9X5D3FLECSD4KNCIXBAN
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	05h16m17s.79
RA (top/left)	05h17m47s.59
RA (top/right)	05h14m48s.38
RA (bottom/right)	05h14m48s.55
RA (bottom/left)	05h17m46s.36

Dec (center)	+34°27′28″.2
Dec (top/left)	+34°45′19″.8
Dec (top/right)	+34°45′22″.6
Dec (bottom/right)	+34°09′31″.3
Dec (bottom/left)	+34°09′24″.9

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