White balance for long exposures?

[Ad@m]

Just wondering for next time since my last attempt at star trails I ended up with very warm skys and blue stars. Is there a "right" setting for this? I ended up having to correct WB in Lightroom and then desaturate the blue out of the stars. Any help is appreciated.

[Sorarse]

If you ended up with warm skies and cool stars, I would suggest that the problem isn't your white balance. The warm skies is more likely to be a result of light pollution or atmosphere glow, which you should be able to correct in post processing.

[Nighthound]

Set white balance to "auto".

The blue stars are a result of chromatic aberration or misalignment of spectral color at the focal plane. To simplify the lens or lenses you're using are not color corrected. Optics that are corrected are very pricey, i.e. true APO(triple objective or more) refractor telescopes.

I have a doublet APO refractor and although it is corrected well it still displays some false color. Noel Carboni's Astro Tools for Photoshop has a reduction feature for the blue halos. Difficult to get it all out when using camera lenses.

As far as the warm background, as long as the color balance is correct it's fine. I shoot for R=25, B=25, G=25. It may appear warmer than it is because of the cool blue halos on the stars.

[Ad@m]

Great, thanks for the help.

Sorarse, you have a good point, it was pretty dark where I was but there were a few small towns nearby maybe producing the light pollution.

Nighthound, the lens I used was a 24-105 f/4L @ 24mm wide open. Ive never seen CA on that lens wide open but it is no telescope. I guess Ill just have to deal with it in PP.

[Nighthound]

Great, thanks for the help.

Sorarse, you have a good point, it was pretty dark where I was but there were a few small towns nearby maybe producing the light pollution.

Nighthound, the lens I used was a 24-105 f/4L @ 24mm wide open. Ive never seen CA on that lens wide open but it is no telescope. I guess Ill just have to deal with it in PP.

I'm not all that bothered with some CA. I really don't do anything to reduce it with my Sky 90. Some purists are bothered by it, heck I'm just happy if I can get a full night of data without tracking errors.

[rabidcow]

Try daylight WB, works well for night sky.