Help With My Image

[pscammp]

Hi all,
    I have just started a new trial licence and i have an issue i need help on if anyone is up for it.

I had a go at what i would call stacking some subs (Got to get my head around PI's terminology....Sorry)

Made master Flats, Darks & Bias's according to that written tutorial on the PI site. Then i registered, itegrated etc

The resulting file looks superb compared to any i have done in DSS, it appears that the master Flat actually done its
job with ref to getting rid of vignetting etc so i was happy as larry at that point. My subject is M31 here where all the image
and calibration files were captured with a modded Canon 1000D with a 2" IDAS P2 light pollution filter on the front. Scope
is a 10" Newt at F4 autoguided on a NEQ-6 Pro mount in case anyone wonders. Backyard EOS was used for data capture.

I  found a sequence of tutorials on youtube by Jason Brown where he is processing M33 so i decided this would be a great
place to start.

1. In his tutorial part 1 he does a linear stretch and ends up with a green image which he puts down to chromatic noise, he
    then uses the SCNR tool and uses 'Green' to get rid of it.....

    When i did it, my colour was almost completely red so i also used the SCNR tool set to red to remove it. The result pretty
    much looked like jasons except it looks a bit green, when zooming real close, He has black, blue & brown pixels dominating
    but my close up appears to have magenta pixels as opposed to brown ones. 
    Is this quite normal or does this show a problem with my image   ?

2. All other processes along the video's seemed to work & flow really well until i got to 'Part 7'. Here he uses the Colour Saturation
    Tool to increase the colours in M33's spiral arms etc.

    When i did this part i had no increased colour whatsoever even with the 'Range' selector set to 10. I even tried moving the whole
    line all the way up so all colours would increase but mainly all i noticed was Green in and around the dark matter area's. I had no
    masks in place at this point as i disabled them to see it that would make any difference but alas...Noooo

    Somethings not right here as the slight colouring at the top was a bit of green, is there, again, something wrong with my image   

Obviously, im sure it's difficult for anyone to be helpful unless they have my image to check out so i have loaded it up on my dropbox,
feel free to check it out and any help or identification of what i have done wrong would be greatfully appreciated.

The file is the one where the Master Flat, Dark and Bias files have been processed on the lights in the way which was described.

https://dl.dropboxusercontent.com/u/4938813/M31_PI_Cal_and_Stack.fit 
(realy hope this Public link works)

I so hope someone can help, i was so excited last night

Many Thanks
Paul
   
   

[pfile]

nothing wrong with the image, i did a very quick and dirty processing, and i mean dirty - the DBE needs a lot more work. the image has more potential than what i've shown here and the core has gotten a little ugly due to the order in which i did things.

perhaps when you were trying to boost the color the galaxy was masked?

rob

[pscammp]

Hey pfile,
     Many thanks for trying that out for me, obviously it's something im doing wrong somewhere.

Us newbies are so annoying   

So when applying the linear auto stretch & my image goes red (when jasons went green) is that
normal too as my result was a green hue after applying the SCNR tool set to red, i remember reading
somewhere that green should'nt exist in an astro image, why does it go from red to green in this process  ?

Regards
Paul

[AstroScience]

Hi Paul,
when you apply STF, try to unlink the channels and hit Ctrl+A again. Small chain symbol on the left of STF tool.

[pfile]

yes as astroscience says just unlink the channels in STF. it's pretty common for one channel to overpower the others for a variety of reasons.

the right way to fix the colors is to do backgroundneutralization and color calibration, but the AutoSTF usually balances the channels if the channels are unlocked. also, DBE tends to neutralize the background.

rob

[Carlos Milovic]

Don't apply SCNR to the red or blue channels. You are destroying data.

[pfile]

well, there are no green stars but that's just due to human vision and the width of the spectrum that different types of stars output. but your images can certainly look green for a variety of reasons. anyway as carlos says SCNR is not really the way to fix the color balance problems in this image. the amount of green reduction in this image that's necessary is relatively small, actually.

rob

[james7]

Also, before you do the DBE make certain that you've cropped out any areas around the edges of the image that contain incomplete data (usually caused by registration shifts between the subframes in your stack). On my images these generally show up as darker or multicolored, straight boundaries near to the edges of the master integration.

[pscammp]

Many Thanks all,
    Not applying SCNR using the red channel and unlinking the channels in the STF solved it, and i did crop edges too.

Made an image following those 12 tut's (with exception to the above points) and did'nt get a bad result considering
its my first time in PI, better than my results using DSS & Gimp for sure.

One thing i did notice though, in the STF, i could'nt tell if the channels were linked or unlinked, the little icon looks
identical either way.

Tried to save my result as a Tiff but the image looked, shall we say...Bayered...with a big black border to the right,
Whats that all about then  ? Never had a Tiff do that before, PNG, JPG & BMP worked though  !!!

Anyway, time to soldier on as they say.

Thanks Again everyone
Paul