California Nebula

California Nebula

Buy a Print

Name (required)

Email (required)

Address (required)

Phone Number (required)

Select Type

Select Format

Select Size

Select Size

Select Size

Select Size

Sectional prints are available in dimensions that are multiples of 20cm (about 8 inches). The following sizes and prices are for example only. Please select the desired width below to get a quotation.

Size Price
80x60cm $90
120x80cm $140
160x120cm $210

Select Width

Order Notes

This nebula contains all 3 of the target spectral lines, hydrogen-alpha, sulphur-2, and oxygen-3. But I didn’t get enough OIII data to do anything other than balance the color of the stars. I was using 8 minute sub-exposures because that’s where bright stars were starting to saturate, but I think I would need to go to longer subs to get any OIII nebulosity. The SII image has significant nebulosity, but not a lot of differentiation from the H-a image, so longer subs would probably help there as well.

This is a 2×1 mosaic and, unusually, doubles the longer axis. Not many targets are as elongated as the California Nebula.

The channel assignments are R=H-a, G=SII, B=OIII. However, I tweaked the hue slightly after combining the channels because this shows the difference between H-a and SII more clearly.

Guiding was excellent most of the time, but the wind seemed to affect it at times.

Scope: AT111EDT at f/5.6
Mount: AP Mach1
Camera: QSI 583 at –25C
Exposure: 10 x 480s H-a, 10 x 480s S-2, 6 X 480s O-3 (2x each for mosaic) (7 hrs total)

About Greg Marshall

I am a retired electronics engineer and after a few months of enjoying my leisure I began to miss doing product development. My astronomy hobby always needed new solutions to unique problems, so I decided that whenever I came up with a good solution I would try to make it available to others.

Leave a comment