It has been a long time between posts here unfortunately but I finally got the chance to take a step forward to auto-guiding under a dark sky at SPSP last week.
This was taken through the little Astro-tech AT65EDQ, using 9 x 5 min subs (plus darks), on the AZ-EQ6-GT mount through a newly astro-modded Pentax K-5 IIS DSLR.
That a good effort Pete and the green will be easy to manage with the right tools depending on the software that you are using for post processing. There is a slight gradient from left to right across the image. With the exception of a slight elongation in the bottom left corner the stars are nice and round across the image. Very nice detail in the nebulosity and the colours in the reflection and emission nebulae great. All in all 'tis looking pretty good Pete.
Thanks Rex, Bart, Rodney and Mike. That's exactly the kind of feedback I'm looking for.
I can definitely see the green cast now that it has been pointed out (& processed out by Bart). Interestingly as this was the first time trying out the new modded camera I tried a custom white-balance and it came out very green! I reverted back to daylight white-balance after the first sub and I suspect the green cast is more about my post-processing tweaks. I'm using DSS & PS CS5.
The stars at bottom left are a bit weird. Not sure if the camera was not quite orthogonal. I think the AT65EDQ has an in-built CAA so might have to investigate that. Other issue I can see are the blue 'blooms' around the brighter stars. There might have been a slight dewing up of the objective as I was concentrating on the laptop/PHD2 and didn't think to adjust the dew-heater before capturing the subs. Pretty sure the scope has no noticeable CA as I saw none on my unguided test images.
I did a repro on this with some proper noise reduction masks and boosted the colour. Not sure if I've actually overdone the colour now.
I also worked on the star shapes a bit as best I could. They weren't uniform across the field so I think I had some tilt in the system. Not sure what to do about that other than buy a new 2" nose-piece (the old one is pretty rough and ready and really needs replacing anyway).
Oh I also got rid of the excess green
Original Astrobin link in the first post has the repro uploaded in higher-res.
Last edited by Retrograde; 25-06-2016 at 01:01 PM.
Reason: Additional info
The repro looks really good, I don't think the boosted colour is overdone. I reckon if you are shooting in colour then flaunt it. Which is what I do with my images, but others will disagree on that concept.
The star shapes look OK, there are many causes of eggy stars, polar alignment, guiding, tilt, field rotation, collimation. If they can be repaired in post processing software then it is not really a disaster.
Looking great Peter, very rich & vibrant. Some detail missing in the lagoon though, not sure why but looks a bit smeared?
Nicely composed image too, well done
The repro looks really good, I don't think the boosted colour is overdone. I reckon if you are shooting in colour then flaunt it. Which is what I do with my images, but others will disagree on that concept.
The star shapes look OK, there are many causes of eggy stars, polar alignment, guiding, tilt, field rotation, collimation. If they can be repaired in post processing software then it is not really a disaster.
Cheers
Bill
Thanks Bill! I'm pretty sure the star shapes were due to something related to the OTA. This was basically first light with the little AT65 and another image with it that weekend showed similar (but not quite so bad) issues but when I used a different OTA that weekend on the same mount I had no such problems.
Quote:
Originally Posted by zardos123
Yep thats looking really good, your best shot to date by far, got to be wraped with that
Well done
Regards brad
Thanks Brad!
Quote:
Originally Posted by Andy01
Looking great Peter, very rich & vibrant. Some detail missing in the lagoon though, not sure why but looks a bit smeared?
Nicely composed image too, well done
Thanks Andy. Some of the bright stars are showing blue halos (and not all of it is due to reflection nebulosity ) - it's possible because I was focusing on the autoguiding part so closely I forgot to turn up the dew heater and this may have affected the brighter parts of the Lagoon (plus I had some tilt as discussed with Bill above).
but as Barts tweek shows, it was a bit green 
) - it's possible because I was focusing on the autoguiding part so closely I forgot to turn up the dew heater and this may have affected the brighter parts of the Lagoon (plus I had some tilt as discussed with Bill above).
