Hey Hemi, here are my thoughts, hopefully they help until someone more experienced chimes in:
>> No calibration frames. 294 is cooled to the max: gets to about -10 max, as I live in the tropics.
Flats will obviously help with vignetting, it's always worth taking a few mins to capture those. Simple twilight sky or t-shirt flats are fine to start with. I tend to avoid running the cooler at max power although that's more of a gut-feel thing, doesn't seem right to run at max for several hours.
>>Im getting a lot of hot pixels. Is this normal at this length of exposure?
What gain are you using? I tend not to use Darks and don't have an obvious problem with hot pixels at 300 gain and 60s exposures. If you post a few sample dark frames (at different gains and exposure lengths) then we can take a look.
>> Can someone tell me what the finger print like smudge is, the optical train appears clean.
It looks like slight condensation to me. Did it appear toward the end of the session or permanent fixture? High humidity at your location?
>> Should I expect vignetting with this setup? Or do I need to alter the spacing? currently reducer is directly on the SCT, then a Baader click lock, with 1.25 adapter and then the nose piece of the camera.
I think the 1.25 adapter is causing the vignetting, suggest switching to a T-adapter behind the reducer and then T2 extensions all the way to the camera. I don't know the correct spacing for the Meade .63 but the Celestron is 105mm from back of reducer to the sensor. The Celestron .63 will give you a corrected field at that distance.
>> Lastly, I am bewildered on how to properly get the WB settings correct. They clearly have a great effect on the stacked image, but how do I set them correctly so the colours are accurate?
There are 2 schools of thought it seems. Some folks use the R and B sliders on the
camera Image Control panel (1 below) to get the RGB peaks aligned in the live view and stacking histograms. Robin (SharpCap developer) has advised against using these camera-level controls and instead advises using the color sliders in the live stacking window (2 below) to adjust the color:
These 3 color sliders move the color peaks relative to each in the DISPLAY histogram only. The 4th slider is saturation and should probably be set lower than I have it here.. worth playing around with while stacking.
The idea is to get the peaks roughly aligned although you may get more pleasing results when slightly misaligned depending on the target. You could try both approaches to see what works best. Keep in mind that accurate color balance is somewhat display-specific. The M51 above looks ok on my laptop but is far too red on my desktop monitor.
Edit: corrected panel name, explained 4th slider and added link to Robin's post on color correction
Edited by cshine, 06 May 2019 - 10:13 PM.