Tonight's feeble effort....

[Kazzmaniandevil]

Managed to stack but can't seem to make sense of curving it or layering image, just seems to get brighter and brighter!!!! 

[Davey-T]

You need to move the black point in to near the histogram to keep the sky dark, don't try to do it all in one go.

Dave

[Kazzmaniandevil]

I have no idea what that means!? 

[Marky1973]

Get on YOU TUBE and search for processing videos - if you look for Doug German Astrophotography, there are a load of tutorials that are great to get started with - they are for photoshop, but the principles are the same in GIMP if you are using that programme?

[Kazzmaniandevil]

I used a couple of the vids that were suggested on this forum. The only problem is (and I think this is what the guy above was referring to) is that my black area starts in the bottom left and I've got no way of moving it across when doing the curving. I'm guessing I might head more dark photos when stacking so the contrast is more obvious?

 

 

[Marky1973]

I'm still learning a lot myself, so might not be the best person to help here, but what subs did you stack and what programme did you use? This might help people with more experience than I diagnose the issue you might be having.

[Kazzmaniandevil]

subs?

[Kazzmaniandevil]

this what I have when changing it from 32 bit to 16bit

[Kazzmaniandevil]

and this is what I have when I try to start curving

[Marky1973]

Subs are the basic pictures you are taking and then stack....so LIGHTS are your actual picture files,. DARKS are the Dark Frame Subs, BIAS (Bias Subs) and FLATS (Flat subs). Stick them all together in a programme like DSS (Deep Sky Stacker) and it will put them all together in a TIFF or FITS file that you can fiddle with in Photoshop. If you only had a few short LIGHT subs in your stack it might be harder to process, so it would help to know how many you had. If you click on the link in my sig, I have a little DSS tutorial on my blog that might help?

Have you tried adjusted the Levels in PS before curves? What does that graph look like?

If you haven't already grabbed a copy, I can recommend Making Every Photon Count - which is available through the site sponsor FLO, which gives a great basic grounding in all things AP from chosing equipment, taking photos and processing them.

I have found it frustrating, but rewarding if you keep at it - each incremental improvement in your own skill/understanding is really rewarding.

[Davey-T]

Start with levels, you should have a histogram type shape with a gap to the left, try moving the left hand pointer near the back of the pointy black bit sticking up
Best to start with levels as it doesn't alter the actual data as opposed to curves.

You can go mad and click on the left hand eye dropper icon at the bottom of the curves window and click somewhere on your background and turn it black, not recommended but gives you an idea, you really need to just click around on things and see the effect, you can always go back.

Dave

Had a quick hack at a screen shot, needs more data and calibration frames

[Kazzmaniandevil]

ok used 12 light frames and 12 darks/ exposure was for 5 seconds each on 800 ISO using a Cannon 350D I'm going to attempt some more tonight (gotta take advantage of the clear skies!)

How many should I look at taking then?

cheers for the assistance.

 

kazz

 

(sorry I've been a nuisance but am certainly struggling with all the new terminology and abbreviations)

[Marky1973]

Depending on what lens you are using...I'm presuming you are using just a DSLR and not a telescope...you could push the exposure to longer. I believe the rule is something like 500/fl to get the exposure. I've never had much luck with just DSLR photography though, so I'm not the expert.

Take as many lights as you can, the more data the better.

Are you shooting in RAW format?

[Kazzmaniandevil]

yes all on RAW and on just the DLSR (not had a great deal of luck on the telescope so thought I would go back to basics(!) on just the camera for the moment. Ive just jumped outside this second and done another load so we will see if that produces anything slightly better.

 

[Marky1973]

Good luck. A lot of this seems to be trial and error and learning as you, so getting out and having a go is the right thing to do!

[Davey-T]

Don't worry about asking any question, you're not being a nuisance, far from it, plenty of folk have been and are in your position so you're helping others .

5 secs isn't very long so take as many exposures as you can experiment with ISO to see how far you can push it although the 350d is a bit noisier than later models I believe.

Dave

[Kazzmaniandevil]

Ok, round two tonight and I still have a Histogram which is all the way to the left. I have no gap.  Is this because I haven't used flats, dark flats or bias (which I still cant figure out what they are) ?

 

 

[Davey-T]

OK here's an example pic, if you open the curves window and hold down the CTRL key and click on the sky background it will put a black marker on the curve line, you can move this up and down to alter the background level, in this I've pulled it down to darken it.

Dave

 

[Kazzmaniandevil]

Yup done that but histogram still refuses to budge to middle!! (Will post pics in a tic )

[Kazzmaniandevil]

this is tonight's photos having stacked them using darks and lights. I had 34 lights and about 10 darks. as you can see I have included the curve graph

[Kazzmaniandevil]

and this is once I had done the curves and wanted to adjust levels. as you can see I have nothing in the middle any more?!

[OutThereSomewhere]

@Kazzmaniandevil: In your last screenshot, drag the middle slider (just above the 1.00 box) about a quarter of the way to the left. Then click OK. Then get the levels dialogue box again and repeat this about 5 times. This will bring the histogram "hump" nearer to the middle. You should then see some more of the nebula.

 

[OutThereSomewhere]

Then you can use curves to fine tune the image.

[Kazzmaniandevil]

now would you believe it, not moving it a quarter but a slither to the left actually worked! I just kept repeating that till I finally started to see the historgram move across! now to try the curves!!

 

[Marky1973]

Nice one - as Dave says above, don't try and do it all at once, but little and often!