First Light Modded 1100D - Flame and Horsey

[Gina]

Taken last night with very little time. A couple of dozen subs but the first few were before it got really dark and the last few suffered from some obscuring by the obsy and a touch of LP. I think this was probably my last chance at this target this time round unless the clouds go away by dark tonight.

[swag72]

What length subs are you taking? Is this through the scope or eyepiece? How many subs in total

I have read your trials and tribulations with modding your camera - Having looked at the pictures you are taking with it, I've not seen so much noise on a DSLR as I am seeing here. I used my modded 1000D for a while and even though the noise bugged me, it was nothing compared to this. Is there possibly some issue with your mod? Are these massive crops? DSLR's are proving to be so very capable now, I am a little surprised by this if I'm honest.

[Nadeem Shah]

Hi

Can we have the full frame please, like sara im quite bemused why it's so noisy as well !

Unless it's been stretched too much...

[Gina]

I'll sort out a full size JPEG shortly, meanwhile I saved the unadjusted TIFF from DSS and uploaded it - here's the link (70MB file size) :-

filehosting.org - download page for Flame-unadjusted.TIF

[Nadeem Shah]

you have to register your email address there to download

[Ags]

What ISO did you shoot it at?

[Gina]

Here's the full frame from DSS converted from TIFF to JPEG and scaled for here. No extra processing. Not uploaded to Photobucket and linked like before but a direct upload here.

[Gina]

What ISO did you shoot it at?

1600 with 20s exposures and a total of 52 subs though probably a dozen or more rejects.

[badgers]

Looking at the image in PS it just seems to me that there is just simply not enough signal.

Very gentle processing below, taking care not to clip and making small adjustments each time, undoubtedly others could get more out.

Flats and Darks would sort the dust spots and dead pixel trails, and reduce the noise levels a lot.

But I'd imagine this would come out a lot better with 1 minute subs at least ?

[Nadeem Shah]

best I can do with your jpeg

[badgers]

you have to register your email address there to download

10 Minute Mail

does exactly what it says on the tin : )

[Nadeem Shah]

cheers. i'll bookmark that one

[Gina]

No good tonight - patchy cloud - Orion not visible I think I should have used my CLS filter.

[Zakalwe]

Theres not enough signal. It has to be stretched loads to get any detail. Longer subs required (certainly for my rubbish processing skills anyway).

[Gina]

Looking at the image in PS it just seems to me that there is just simply not enough signal.

Unfortunately I was limited by the time between getting dark and Orion disappearing.

Very gentle processing below, taking care not to clip and making small adjustments each time, undoubtedly others could get more out.

That's better

Flats and Darks would sort the dust spots and dead pixel trails, and reduce the noise levels a lot.

I have some darks I think I can try. Must sort something for taking flats.

But I'd imagine this would come out a lot better with 1 minute subs at least ?

Yes, I think you're right.

[Gina]

best I can do with your jpeg

Yes, that's better - thanks

[Ags]

I think 40 seconds at ISO 800 would be better, or 80 seconds at ISO 400. The noise on the 1100D shoots up over ISO 400.

[badgers]

Considering it was only 20second subs Gina, I'd be very encouraged.

Nothing wrong with the camera or mod !

[Gina]

Theres not enough signal. It has to be stretched loads to get any detail. Longer subs required (certainly for my rubbish processing skills anyway).

Yes, it needs more time. I had a quick try first off with a few different exposure times - I thought I chose the best.

The apparent noise is due to over stretching which brings out the variation in pixel sensitivity in the sensor chip, I reckon. The darks at those settings are well below the bottom end of the light histogram. The S/N ratio is fine but there is simply not enough signal.

[Gina]

I'm running DSS again and this time adding in the darks. I also found a few lights I had missed. I doubt the darks will make much difference as the dark signal is way below anything significant in the lights. Will remove any hot pixels, of course. There are 61 lights and 15 darks.

Actually, I'm quite pleased to have got an image in which I can see the flame and horsehead.

[Zakalwe]

Actually, I'm quite pleased to have got an image in which I can see the flame and horsehead.

So you should be. You managed to find it, frame it, focus it, track it and photo it:icon_salut:.

Drop the ISO and get some longer subs and you're sorted.

[Gina]

Thank you

[JimStan]

A modded camera is certainly the way to go on that subject. I have tried to get the horse with an un-modded Nikon, and it is a real struggle.

Don't push the processing too much, as others have suggested, and get more photons to stack, and you should have a fine image, Gina !

Jim S.

[swag72]

The edits show that the initial processing was a little too much and also, I believe that the crop is too severe. I know that when I had my DSLR I wanted to crop everything in so that it was nice and big in the screen, but if you want a pretty picture, than I found that was not generally the way to go. A serious crop gave rise to all sorts of problems, such as lack of resolution and noise.

Better to have the target smaller and well presented as in the edits, in my opinion.

[Gina]

The edits show that the initial processing was a little too much and also, I believe that the crop is too severe. I know that when I had my DSLR I wanted to crop everything in so that it was nice and big in the screen, but if you want a pretty picture, than I found that was not generally the way to go. A serious crop gave rise to all sorts of problems, such as lack of resolution and noise.

Better to have the target smaller and well presented as in the edits, in my opinion.

Thank you Sara Yes, I think you're right. Here's another go with no cropping and less severe stretching.