Help/Advice needed

[martin_h]

I'm having great problems in getting the best I can from my data, I dont know if its me or the data (me probably).

Can anyone have a go at this stack.TIF

and tell me if there are any problems with it..

Its a stack of 9 x 10 min subs with darks, flats, and bias calibrated, this is the stack straight out of DSS with no tweeking at all done to it.

Thanks in advance for any advice given.

Martin

[adamsp123]

Hi Martin,

Maybe....just maybe

When DSS finished it loads a pic and at the bottom you see a curve with the RGB histograms on top if the RGB are aligned select "linked settings" and move the RGB up the curve hit apply.

Here are a couple of screenshots to illustrate from a stack of 5 subs - even a small move along the curve makes a hell of a difference. First as it came out second with the tweak.

HTH.

Pete

[martin_h]

- even a small move along the curve makes a hell of a difference.

How much is a small move tho - what am I actually looking for? The Image 'just' in view, the Image in 'full' view? I assume that if moved to far it will be over cooked?

[Cloudwatcher]

It's a nebula! You didn't say anything about it being a nebula! I don't do nebulae............

see why below.

[Ben Ritchie]

What camera are you using? There's some signal in there, but it needs stretching pretty hard - are you using an unmodified DSLR by any chance?

As an aside, you don't need bias if you're using same-length darks.

[adamsp123]

How much is a small move tho - what am I actually looking for? The Image 'just' in view, the Image in 'full' view? I assume that if moved to far it will be over cooked?

If you look at my 2 pics you can see how far I have moved the RGB peaks as an example, you use the RGB sliders to move it and BTW if it looks wrong (eg too bright and washed out) after applying the change you can use the back button.

[Cloudwatcher]

Have a heart Martin,tell us it's part of ic1805 you captured....... looks like it in the attached rotated re-work.

[martin_h]

BINGO!!

yes it is the heart....and you have answerd my question, looking at your image .....its my processing that is pants...ho hum

Have a heart Martin,tell us it's part of ic1805 you captured....... looks like it in the attached rotated re-work.

[martin_h]

What camera are you using? There's some signal in there, but it needs stretching pretty hard - are you using an unmodified DSLR by any chance?

As an aside, you don't need bias if you're using same-length darks.

Its a QHY8 CCD...and you, like everyone else I've asked have said the same....'I's in there but hard to get out' My question is WHY?????? Do I need longer subs??? these were 10mins.

Do I need more subs?

Acording to the DSS workflow chart I do need bias as well as darks ?

[Ben Ritchie]

Acording to the DSS workflow chart I do need bias as well as darks ?

Darks are effectively bias + thermal noise, so your darks already contain the bias.

You only need both if you want to scale a dark frame to match an exposure of the same temperature but different integration time - e.g. a 5-minute dark and a 10-minute exposure. In that case you subtract bias, scale the dark current to match the lights and then add the bias back again.

[ollypenrice]

Be aware that the Heart is terribly faint at the best of times. I recently shot it with an f3.9 Takahashi and you don't get too much even then. Not double subtracting the bias might help quite a bit.

Olly