I am trying to figure out how to custom set a number white balance right now so that I can just leave my camera on a white balance suitable for astrophotography.

Edit: I assume 8200 K counts as an extreme white balance, correct?

Set it for daylight and leave it.
You can fine tune later in post.

Here is a longer article on white balance and astrophotography:

Using a Custom White Balance

Isaac,

This is what I made of your file that you shared. I used the one that you provided with the reset white balance.

Did all the processing in PixInsight.

Steps:
Dynamic Background Extraction to eliminate some gradients
Masked Stretch
Color balance
Histogram Stretch to reset black point
Created luminance mask
Noise Reduction with mask
Masked Unsharp to bring back details on the high SNR areas
Masked Curves to drive the lower SNR areas towards black to minimize the grainy background glow

Plate solve results:
Projection origin.. [2459.416059 1629.742835]pix -> [RA:+05 35 11.59 Dec:-05 21 26.81]
Resolution ........ 2.558 arcsec/pix
Rotation .......... -58.067 deg
Focal ............. 403.19 mm
Pixel size ........ 5.00 um
Field of view ..... 3d 30' 5.5" x 2d 19' 9.1"
Image center ...... RA: 05 35 11.507 Dec: -05 21 39.81
Image bounds:
top-left ....... RA: 05 34 57.516 Dec: -03 15 46.20
top-right ...... RA: 05 27 30.589 Dec: -06 13 36.08
bottom-left .... RA: 05 42 51.118 Dec: -04 29 22.04
bottom-right ... RA: 05 35 25.596 Dec: -07 27 33.36


Here's a link to the full size jpg:
https://www.dropbox.com/s/san5fjybw8e5m57/20150923-M42Trial.jpg?dl=0
https://www.dropbox.com/s/r7ojwhkb4f89d83/20150923-M42Trial_Annotated.jpg?dl=0

Full size TIF:
https://www.dropbox.com/s/j6lar7fn76b91p7/M42Trial.tif?dl=0
https://www.dropbox.com/s/shkd5b2qlxumikz/M42Trial_Annotated.tif?dl=0






What I'd suggest doing next time:

Get to a darker site. There's still a lot of background glow. This area has a lot of dust in it and this is only visible with longer exposures and darker skies.

Shoot when your target is high in the sky, at least 40 degrees above the horizon. This will minimize the amount of atmospheric distortion and filtering of the light.

Lower your ISO setting. Many of the stars are clipped and thus the true color is lost.

More subs. Lots more. With such short durations, I'd suggest at least 64.

What ISO would you recommend? Also, I went out again last night but even after 6 precise calibrations, the O-GPS1 wouldn't give me good tracking. Any typical reasons why this would be? I hate wasting so much gas and time unnecessarily

There are other users that know the O GPS unit and the way it works.

I'd suggest halving your ISO and seeing what you get - try ISO 400. Remember, digital ISO is really amplifier gain. There's no new signal being recorded as the sensor is not magically more sensitive. What is of concern with CMOS sensors is making sure that the readout noise from the CMOS is optimized with regard to the low end signal. There are resources on the Cloudy Nights forum as well as Craig Stark's paper on the Canon system.

My K10D is CCD based and so I run it at ISO 100 to maximize the dynamic range. There are other sources of noise in that camera that swamp readout noise (amp glow, etc) so the low ISO makes sense.

I have had that happen to me on occasion and it is discouraging after driving and spending time n money........sometimes removing all batteries and starting from scratch helps other times it is just maddening but have not had that happen lately......although I have been using rather short focal lengths.....14, 28 and a few 50......however want to go to 135, 200 & 300 since milky way season is pretty much over for now.........hopefully better results with Andromeda n the orion nebula thingy

Smigol are there any entrance level mounts that are worth looking at for just DSLR tracking, no telescope? I doubt I can afford a combo, but last night irked me so much with the astrotracer. I also always worry about my lens as I am swinging my DSLR around.

My camera setup weighs maybe 7 lbs. I just want to explore this realm fully and while the astrotracer is awesome it is still limited.

@Isaac T Haven't had the time yet for the pp of your Orion files but should be able to get to it before long. As I work with PSE 11 and some topaz add-ons it's likely not to be as sharp as smigol treatment but it will be interesting to compare. The astrotracer function is indeed not always consistent. When what you describe happens to me I tend to redo calibration pointing in a direction at 90° with the one I just did. Usually helps. Like Aaron28 my favorite lenses are short: 28, 50, and 105 mm, and from time to time 200 mm.. I can do 3 to 4 min with the 28 without calibrating. The 200 requires a good calibration to get sharp stars at 40 s. The astrotracer is great for starscapes and other wide field shots. If deep sky is really your thing than an equatorial mount is pretty much required. But then there's the added bulk.. and setup time.. and money...

As for iso I tend to crank it up quite a bit (1600 to 3200 range) and stack at least 10 shots to keep noise under control. Smigol discussion of the topic is very very interesting, . I crank up iso to move the histogram away from the left side, I'm afraid lower iso will actually mean more noise coming from the more agressive post-processing needed to bring up image density. I will definitely do some tests.

Isaac,

Regarding entry level mounts that would be good for a DSLR/lens combo, I highly suggest browsing Astromart.com.

You'll see prices of things second hand and get a feel for what has the longest shelf life.

Getting used gear helps keep the budget reasonable.

Note that once you start going with tracking mounts, you'll have to figure out autoguiding and that's a slippery slope of bringing more and more gear out to the field!

Eventually, you'll end up like me, driving a Prius so laden with gear that it will bottom-out on rough roads.

One of the biggest benefits of the latest Sony CMOS sensors used in recent Pentax cameras is the low readout noise. One can actually get away without using any darks if you are lazy without too much penalty. I agree with Steven that the more subs, the better.

Jack

Finally had time to have a crack at the orion files. this is like a poor man's solution to deep sky imagery and the final result has more noise and couldn't get as nice a color balance nor as much detail in the central parts as smigol image. So I guess it really pays to get the right tools and learn how to use them!

What I did was apply level correction on each channel with pse11, tweeked the hue by +0.02, applied topaz adjust adaptative exposure tool (sort of hdr treatment), applied topaz clarity micro contrast adjustments and finally applied "color blotch reduction" of astronomy tools 1.6 by Pro Digital Software to help get a darker sky.

Reliability of the O-GPS1 tracking was an issue in many discussions on this topic. I have it as a tool for my K-5 and "built-in" my K-3 II. Comming to longer lenses and having only a little time for this hobby I got increasingly frustrated about it. Wide lenses (10-20 mm) always produce trails in the edges with Astrotracer.

I now only use it for the "normal" length lenses in skyscape photos and really like it there.

For deep space objects, sun and moon I uses the inexpensice but reliable Skywatcher Star Adventurer in this type (photo: TeleskopExpress):"Sky-Watcher Star Adventurer Motorized Mount Astro Package"




It is quite small, of light weight (1.4 kg + counterweight), carries up to 5 kg, fits into a small case and is easy to set up for use on a stable (normal) tripod. It gives me > 3 minutes of exposure time without trailing stars with a 200 mm lens + 1,4x TC.That allows me to use lower ISO and stop down the lens for better focus and sharpness. With Astrotracer and a 200 mm lens I am at lowest F-stop and above ISO 1.600. With Star Adventurer I can use ISO 800-1.600 and can stop down 2 stops. The quantity of shots to get good results reduced dramatically. Longer lenses than 200 mm + 1.4 TC not yet tested, waiting for clear skies to test the new (old) SMC Pentax-A 400 mm 1:5.6.

It was the biggest step forward for me in astrophotos. Besides the longer exposure time best conveniance is the possibility to set the system up in the early (dark) evening, let it follow and shoot the target autonomously (the mount triggers camera or use interval timer or remote) and collect the results in the next morning without staying awake the whole night and readjust the camera as it is necessary with Astrotracer.

I think the Astro Package Version costs about 330 $ at the moment.

Hey guys what are your thoughts on the iOptron ZEQ25? It is an interesting design but I keep reading good things on it. I want to get something(if I get something) that will also allow me the freedom to add an actual telescope if I ever get the desire to. I just don't want the Equatorial Mount I get to limit me, because I have a feeling that I would end up needing to replace it.

Isaac,

I know a fellow that's used the iOptron mount for astro work. I know that it's worked well for him when he started using it. I am not sure if he has continued using it after the initial few times.

I'll drop him a line and see what he thinks.

Your local astro group might have a gear night where you could talk with people about what works or doesn't.

PeteXL's stripped down mount looks dandy for small DSLR work! Just the kind of thing to set up for time-lapse sequences in the day or night.

Here is a thread on Cloudynights that talks about the iOptron ZEQ25 mount: iOptron ZEQ25, initial impressions - Mounts - Cloudy Nights

Is works fine for a DSLR with a long lens but will not replace a 3,000$ mount . With the "L-bar" (dont know the english word) you can even mount two cameras at the same time. I tried it and shot north america nebula @100 mm with an OM- D and M13 with a K5 @300 mm x 1.4 TC in parallel. it worked perfect. Both cams were triggered by th built-in 100sec. interval timer of the mount.