DeepSkyStacker

[Jon Foster]

Ok, so I'm going to give DSS a try with some shots I'll be taking later this month and I was just reading the online manual and FAQ. Now I have a few questions for the people who actually use it etc.


When you are shooting, how many shots do you usually take to insure a decent stack?
Do you use the same camera settings for ever shot?
What camera settings give the best results? I like to shoot with the lowest ISO possible but the DSS site says to go higher, like ISO 800 to 1000.
Is there a good starting point for the number of light, dark, flat and bias images to use?
Is there a optimal exposure time to limit star trails when using a stationary mount?
Everyone shoots RAW (CR2) and stacks the images with DSS without any other work beforehand right?Thanks!

Jon.

[chris.bailey]

1) As many as you can. The more you take, the lower the noise and the more detail you can tweak out. I commonly shoot 6 minute exposures and aim for 2 hours worth so 20.

2) Yes

3) ISO 800

4) Dont bother with darks or flats to start with. Darks/Bias I typically take 100.

5) Depends on you targets location in the sky and what lens. Trial an error but 20 seconds is a good starting point at widish angles.

6) Yep. Plain old RAW works best

[MintMark]

I'm a relative beginner, but here are my answers anyway :)

1. The more pictures the better improvement in signal to noise ratio. I have used as few as 6. At the moment I'm using 20-30 pictures.

2. Yes. More importantly don't move the camera at all otherwise DSS can have trouble registering the images with each other.

3. I follow the advice to get the histogram peak away from the left hand side. My longest exposure time is limited to avoid star trails. Then I boost ISO and widen the aperture to get the histogram away from the left. Usually I end up wide open at ISO 1600, but sometimes there is some leeway.

4. I use long exposure noise reduction (dark frame subtraction in the camera) and no dark, bias or flat frames. Light frames... the more the merrier.

5. Yes, there are formulae. It depends on focal length and how close your subject is to the celestial equator (where it moves fastest) and the resolution of the sensor and how picky you want to be...

For example, http://velatron.com/dca/Tripod/ or
http://www.astropix.com/GADC/SAMPLE7/SAMPLE7.HTM

6. Yes, I shoot raw and stack them in DSS. Plenty of fiddling afterwards though.

Hope that helps.

[Sorarse]

The only time I tried DSS the resulting image came out with a uniform grey background sky, with white dots for the stars; absolutely no colour whatsoever. This was with JPGs so it either doesn't work with JPGs or I had some settings incorrectly set.

[Jon Foster]

Thanks for the replies guys. We'll be above the 45 parallel so I won't push the exposure times too much. I'll play around with a few shots before hand. My widest lens is the 18-55 non IS kit lens so I'll be trying that first. It should be fun if nothing else and a good trial for the new timer remote. We'll be there several nights so hopefully we'll have plenty of opportunities for a clear cool sky...

Jon.

[Adrena1in]

The only time I tried DSS the resulting image came out with a uniform grey background sky, with white dots for the stars; absolutely no colour whatsoever. This was with JPGs so it either doesn't work with JPGs or I had some settings incorrectly set.
The resulting image within DSS always looks bright grey for me too. And I have always used JPGs because I can't seem to get good results with RAWs for some reason. But once I save the TIFF and open it in PS or something it's fine. I never bother with adjusting the image in DSS...all my editing is done elsewhere.

[A.S.I.G.N. Observatory]

The resulting image within DSS always looks bright grey for me too. And I have always used JPGs because I can't seem to get good results with RAWs for some reason. But once I save the TIFF and open it in PS or something it's fine. I never bother with adjusting the image in DSS...all my editing is done elsewhere.

I have heard this many times. This IS the way DSS will process and stack. The thing to do is go into the midtone shadows sliders, then bump the saturation, tweak the shadows and highlights until it looks semi decent.

After that you can save it as a TIFF and go have a play in whatever editing PP program you like.

Baz.

[spit]

try editing the autosave file, then compare it to the save-as file

[Jon Foster]

I was hoping to try a stack with shots taken this weekend but our plans changed and I wasn't able to head out of town to get the shots. Argh. I'll have to try for another weekend before winter sets in and we can't camp...

Jon.