NGC2403 (Caldwell 7) in RGB + HO (Mau_Bard)

NGC2403 (Caldwell 7) in RGB + HO

Revision title: v2

Weather has not been favorable in the last weeks, therefore I was more than happy to catch the few-hours clear sky opportunity in two consecutive nights, despite wind and full moon, and capture this lovely galaxy that was on my wish-list since long.

This was the first time I have been enriching RGB signal with H-alpha and OIII.

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NGC 2403 (also known as Caldwell 7) is an intermediate spiral galaxy in the constellation Camelopardalis, in the corner close to Ursa Maior. It is an outlying member of the M81 Group, and is approximately 9.6 million light-years distant.
It bears a similarity to M33, being about 50,000 light years in diameter and containing numerous star-forming H II regions. The northern spiral arm connects it to the star forming region NGC 2404.
NGC 2404 is 940 light-years in diameter, making it one of the largest known H II regions. This H II region represents striking similarity with NGC 604 in M33, both in size and location in galaxy.

There have been two reported supernovae in the galaxy: SN 1954J, which attained a magnitude of 16 at its brightest, and SN 2004dj. SN 2004dj was the nearest and brightest supernova in the past 17 years. It is currently (2021) the nearest and brightest supernova in 21st century.

The galaxy was discovered by William Herschel in 1788. Edwin Hubble detected Cepheid variables in NGC 2403 using the Hale telescope, making it the first galaxy beyond the Local Group within which a Cepheid was discovered.

Original
B
C
Final
D

B

Title: Starless

Description: Starless

Uploaded: ...

C

Title: v2 starless

Description: Reprocessed. H-alpha merge with RGB in linear state, and pseudo-luminance in non linear.

Uploaded: ...

D

Title: v2

Description: Reprocessed, with stars

Uploaded: ...

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Status	Advanced success
Started	...
Astrometry.net job	5345991
PixInsight job	RSVBKI5EHHIBUOM9W8JKU3HXCJ96CQ9F
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	07h36m55s.560
RA (top/left)	07h40m50s.909
RA (top/right)	07h32m57s.359
RA (bottom/right)	07h33m05s.683
RA (bottom/left)	07h40m48s.387

Dec (center)	+65°35′32″.70
Dec (top/left)	+65°54′02″.31
Dec (top/right)	+65°53′41″.25
Dec (bottom/right)	+65°16′37″.30
Dec (bottom/left)	+65°16′58″.44

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