NGC 2403 is an intermediate spiral galaxy in the constellation Camelopardalis. It is an outlying member of the M81 Group, and is approximately 8 million light-years distant. The galaxy bears a striking 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 nearby galaxy NGC 2404. NGC 2403 can be observed using 10×50 binoculars.

NGC 2403 was discovered by William Herschel in 1788. Allan Sandage detected Cepheid variables in NGC 2403 using the Hale telescope, giving it the distinction of being the first galaxy beyond our local group within which a Cepheid was discovered. He derived a distance of a mere 8 thousand light years. Today, it is thought to be a thousand times further away at about 8 million light years (2.5 Mpc). [Source Wikipedia].

The image was captured with the Meade 12"LX200, using the Atik 383L+ mono at F7.16. Astronomik's LRGB filters were used.

All subs were taken at 1x1 bin, -10C, and 10 minutes each.

Lum : 30 subs (5.00 hr) on Jan 10th and 11th.

Red : 12 subs (2.00 hr) on Jan 2nd and 18th.

Green : 12 subs (2.00 hr) on Jan 2nd and 18th.

Blue : 13 subs (2.17 hr) on Jan 2nd and 20th.

Processing was done with PixInsight, following (for the most part) kayronjm's tutorial of Feb. 24th. Only L was used to develop the Luminance image. R, G and B were collected for the color mix.

All in all, this is a pretty lousy image. Reasons include

a) Object low on the northern horizon

b) Object sitting directly over city of Burleson resulting in strong light pollution

c) Moon out at various times

d) Use of LRGB filters that have little defense against the above problems.

However, I'm documenting this for record purposes because it is the first use of my Starizona SCT Corrector. The Starizona replaces the old Meade F/6.3 ff/fr and yields a 0.716 focal ratio (vs. the Meade's 0.656). And significantly, the corner stars are (almost) perfect, and the corner vignetting has vanished (at least for this time). Lastly, the removal of the Meade F/6.3 allowed me to tuck the camera assembly 1 5/8" further into the base of the OTA, thus allowing imaging objects closer to the pole. Consequently, the new Starizona appears to be a major success. My light polluted skies simply do not play nice with LRGB filters.

North is up, and this is a very slight crop . Next up, some narrow band.