Need help with postprocessing first nightsky pictures

[Run45]

Hi,

 

Recently took my first nightsky pictures and slowly trying to postprocess what I got.

I stacked them using Deep Space Stacker. Using version 3.3.2 I get a very reddish output picture (see 332-Autosave.tiff) but 3.3.4 produces an almost monochrome picture (334-Autosave.tiff). I attach also the 16 tiffs to this thread.

Is the 3.3.2 output just wrong (did something get fixed in 3.3.4) ? Or is 3.3.2 correct and 3.3.4 wrong ?  My camera is a Canon 100d.  What is the next postprocess step? I guess Photoshop should help me get back all the colours that I cant see in the 334 output. But not sure how and which of the 4 output files to start with.

Could I do it in gimp or other free software ? I tried star tools on all the stacked tiff files but could not get out anything that looked good/reasonable.

I found lots of online material but so much info is out there that it is a bit overwhelming.

The source raw images are similar to the thing I posted here:

https://stargazerslounge.com/applications/core/interface/file/attachment.php?id=219007

 

I feel like I am on the right track but am stuck now .

Thanx for any advice.

 

332-Autosave.tif

332-16bit.TIF

334-Autosave.tif

334-16bit.TIF

[Marky1973]

Images do tend to come out of DSS looking very grey. You are right, you need to get the colour back in through Photoshop/GIMP or whatever other tool you use. You can increase the saturation in DSS if you want to have a quick look to see what colour you might have in the picture, but it is generally not recommended to do this when saving a file for processing elsewhere. I'm still learning myself, but if you have a look on YOUTUBE for Photoshop tutorials, I am sure you will find plenty to help you get started with basic Levels/Curves and Colour processing. There is a lot out there, but I am pretty sure I started out with Doug German's tutorials - part one is here:

https://www.youtube.com/watch?v=Ke3iO9d2Qw8

and that will get you started - there are a number of parts to work through - but I found them very helpful.

 

[Run45]

thanx for link will check it soon.  I am convinced now that my deep space stacker 332 output is wrong and will stay with 334.

Converted the 32 bit tiff into a 16 bit in photoshop and got lots of detail back via the hdr toning gui. Not a lot of colour yet  but feel happier atm ;-) 

 

[Run45]

after playing with lots of sliiders (a bit aimlessly I have to confess) and got this ... still very monochrome ..

going to watch now youtube video mentioned above

[Marky1973]

Yep, stick with 3.3.4 for DSS. Have you aligned the colours in the histogram in DSS as well? I have a very basic tutorial on my blog in the link in my signature if you want to have a look at that - might help.

It can be frustrating trying to get colour out, and I always struggled with PS. STAR TOOLS is well regarded, but needs to be "learnt" - the thing to remember is it isn't "you" it is just the hobby - it is not easy and takes a lot of time and patience - but the images will get better in time. The biggest frustration is the lack of clear skies to keep trying!

 

Good luck!

[Run45]

thanx will have a look.  Clear and dark skies is what I am lacking. Was really lucky that our holiday location had a lot darker skies than our garden ;-).

 

[happy-kat]

Www.budgetastro.net has good  articles and much  can be done in GIMP

[Run45]

Playing around with DSS stacking settings. Got now Vega better resolved. Still not finished watching on the youtube video ... tried the colour alignment in DSS and it looked quite good .. trying to get something similar in PS.

Going to check the budgetastro site next .

[Run45]

this is my result with median stacking and using just curves and levels in PS ... my preview on the camera LCD has lots of more colours (like purple etc) .. not sure yet how to get to those from the DSS output ... if I could get the colours similar to the raw preview of my camera then that would be great.

 

 

[D4N]

Ok so this is what it looks like after I ran you 334 autosave through PI.

Processing was:

Multi scale linear transform

Stretch RGB

RGB in Levels

Contrast stretch RGB

Stretch Saturation

Adjust Green in levels

Adjust black point in levels

DBE

Stretch Saturation

Crop & Scale to 50% to bring it down to a sensible size to post.

 

The main problems are the CA in the corners and the blue bloat on the stars.  I imagine star tools could help with that but a lower f-stop during capture would also be beneficial.

[Run45]

thanx so much ... just got the PI trial license so will try myself

like the colours!

[D4N]

Your welcome, the data is there, just hidden from view

If you use PI it is best to register and stack in PI as well.  You will also be able to take advantage of drizzle, typically DSS will run out of memory if you drizzle a DSLR image but PI is 64 bit so can address a lot more memory and perform more extensive calculations.

[almcl]

I had a quick play with your data in StarTools and this is what I got. As  Dan has said, there's good data there and it's a nice area of Cygnus and friends.  Don't give up on ST - although PI is good too - both require a bit of practice to get the best.

[happy-kat]

If using StarTools you want to use the autosave FITS file.  The autosave TIFF files has been compressed.

StarTools does have Chromatic Aberation (CA) removing tools that are reasonably effective (for blue star bloat).

If you stop your lens down yes you will get a little less light getting in but you will very likely reduce the CA. 2 or so stops slower so if you used f2.5 try f4 next time and see what difference it makes.