#21  
Old 30-09-2009, 04:38 PM
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lesbehrens (Les)
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Originally Posted by toryglen-boy View Post
Les, as asked previously, how many dark frames?
i used 7 darks to 16 light frames. i have some more that i coud try out
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  #22  
Old 30-09-2009, 04:41 PM
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Could be camera settings too.
What's that setting for Adobe?
Colour Space = Adobe RGB
Would that have something to do with it.
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  #23  
Old 30-09-2009, 04:41 PM
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In older models the amplifier that read the chip was left on during the exposure and created an red glow along one edge or in one corner. Later models turn the amp off until readout is needed.

Number of darks shouldn't affect the colour. To me is almost sounds like the darks are being used as flats and divided into the image rather than being subtracted. Or added into the image.
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  #24  
Old 30-09-2009, 04:42 PM
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Quote:
Originally Posted by [1ponders] View Post
In older models the amplifier that read the chip was left on during the exposure and created an red glow along one edge or in one corner. Later models turn the amp off until readout is needed.

Number of darks shouldn't affect the colour. To me is almost sounds like the darks are being used as flats and divided into the image rather than being subtracted. Or added into the image.

how do i fix this?
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  #25  
Old 30-09-2009, 04:47 PM
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Les you need more darks to lights generally and they must be captured under the same conditions as the lights
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  #26  
Old 30-09-2009, 04:49 PM
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Quote:
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Les you need more darks to lights generally and they must be captured under the same conditions as the lights
exactly, having too few darks, can actually introduce noise Les.


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Old 30-09-2009, 04:50 PM
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You don't have amp glow by the look of it. The easiest way would be to sit down with someone that knows DSS (which is where the prob is I think) and go through it step by step.

BTW does the autosave image look like this as well or is this the autosave image?
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  #28  
Old 30-09-2009, 04:55 PM
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Quote:
Originally Posted by TrevorW View Post
Les you need more darks to lights generally and they must be captured under the same conditions as the lights

so u would recomed to take one light then one or two darks after it?
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  #29  
Old 30-09-2009, 05:01 PM
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If you do that then you might as well us the ICNR. The number of darks isn't the problem here. In a dark sky you need more darks than in a light polluted sky because statistical reasons. In a dark sky the more darks you have the better quality of master dark that is produced, however subtracting a master dark made of one dark frame or subtracting a master dark made from 100 dark frames would not produce that affect if subtracted correctly.
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  #30  
Old 30-09-2009, 05:41 PM
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Having more darks than lights is nonsense. You want to capture light. The more signal you have, the less noise you'll have. I'm not saying to take one or two dark frames. Take at least an hour's worth. More if you can. But, it doesn't explicitly have to be more than your light frame count.

Les, you're mixing exposures, aren't you, as in, short exposures along with long exposures, correct?

I am almost certain that your problem is that you're not using matching dark frames to light frames. My guess is that you're using your 10-minute darks to subtract from your short exposures.

Regards,
Humayun
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  #31  
Old 30-09-2009, 06:54 PM
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Humayun I beg to differ from what I've read a lot of imagers collect at least the same number of darks to lights and some even use up too twice the number of darks too their lights

Moreso the darks must be gathered under the same conditions and temperature as the lights

With mulitple exposures of varying length you can stack in DSS as long as the darks correspond to the expsoure time of the lights

ie: 10 x 1 minutes lights (exposures)
the 10 x 1 minutes darks
then 10 x 5 minute lights
then 10 X 5 minute darks etc
once set of flats can be used multiple times
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  #32  
Old 30-09-2009, 07:08 PM
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Quote:
Originally Posted by Octane View Post
Having more darks than lights is nonsense. You want to capture light. The more signal you have, the less noise you'll have. I'm not saying to take one or two dark frames. Take at least an hour's worth. More if you can. But, it doesn't explicitly have to be more than your light frame count.

Les, you're mixing exposures, aren't you, as in, short exposures along with long exposures, correct?

I am almost certain that your problem is that you're not using matching dark frames to light frames. My guess is that you're using your 10-minute darks to subtract from your short exposures.

Regards,
Humayun
yes. ok how do i stack them then? 10 mins with 10mins, 5 mins with 5 mins etc? also by resetting the dss settings i did get a less noisy image
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  #33  
Old 30-09-2009, 07:44 PM
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Les,

I don't use DeepSkyStacker, so can't help you there. I'm sure there's lots of tutorials on the home page.

The general idea, however, is that you want to calibrate your 10-minute light frames, with a 10-minute master dark (master dark is a median combine of all your 10-minute darks). Then, do the same with your shorter exposures; calibrate your short exposure light frames, with the equivalent length master dark.

Once the images are calibrated correctly with the dark frames, and a master flat frame (you will only need one master flat frame, which would be made by median combining many flat frames), you can then median combine the entire lot together.

Example:

10 light frames of 10 minutes each;
10 dark frames of 10 minutes each;
median combine your 10-minute dark frames into a master dark frame;
calibrate (subtract and flat field) each 10 minute light frame with your master dark and master flat frame;

10 dark frames of 5 minutes each;
10 dark frames of 5 minutes each;
median combine your 5-minute dark frames into a master dark frame;
calibrate (subtract and flat field) each 5 minute light frame with your master dark and master flat frame

Now, at this stage you have a completely calibrated set of 10-minute and 5-minute exposures.

You now median combine the both of them for your final stack.

Regards,
Humayun
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  #34  
Old 02-10-2009, 08:08 PM
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lesbehrens (Les)
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hi. what other software is there that can be used to stack the photos?
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  #35  
Old 02-10-2009, 08:21 PM
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Quote:
Originally Posted by lesbehrens View Post
hi. what other software is there that can be used to stack the photos?
DSS is a breeze to use Les, make sure the lights and darks are the same length, drag each into the file window, register checked pictures ...

and away you go ...
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  #36  
Old 12-10-2009, 01:41 PM
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hi. well i have a better outcome. i have reseted DSS and have better image ,but i to have lost some detail. y? will flats and bias frames help?
thanks
les
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  #37  
Old 12-10-2009, 02:35 PM
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Les,

Refer to my post above which details the use of flats. Don't worry about bias frames. The bias is contained within both the darks for your lights as well as your flats.

Regards,
Humayun
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