Help with new CCD camera

[telecasterguru]

I need some help with my new Atik 320E OSC. It is a 2M camera and I used it for the first time on Saturday night and it was my first attempt at CCD imaging.

I have attached 25 minutes (5 x 5min) worth of Eta for advice. 10" GSO RC guided ED80 with PHD. Guiding seemed fine.

I captured with Nebulosity.

Firstly, the camera is cooled but not sure if the cooling comes on with Nebulosity or you have to turn it on with Artemis. Should the cooling stay on with Artemis not running? When I was doing frame and focus images there was a very strong glow in the upper right hand. It was most disconcerting. It was not evident in the images though. This confused me.

Focus is critical. I used a bahtinov mask with the frame and focus but found if hard to get right. I have also been having trouble with the G11 alignment but I think that is just the lack of sky I have to work with.

When I put the stacked images into PS it told me that there was no embedded colour profile in the image. This also confused me as it is supposed to be a OSC camera. I did no processing of this image in PS other than to resize it.

I know this camera has small pixels at 4.4 and the image looks a little oversampled to me. Also a focal length of f8 might not help.

I also did some images with the ed80 to see how they worked out but have not done anything with them yet.

Please help with this.

Frank

[Octane]

The embedded colour profile issue is because whatever software you're using to output the image, is not assigning a colour profile (colour space) to the image.

Photoshop is asking you if you want to assign a profile to the image so that colour management can take place.

Start off by assigning the image the Adobe RGB profile, process your image, convert back to sRGB for the web and save the file.

H

[tlgerdes]

Can't see an alignment problem? Your focus is soft and your stars appear to have a slight lemon shape to them.

How do you align? I can only drift in properly RA, as I cannot see a horizon below 40deg W and 80deg E.

[mithrandir]

How did you process the images? With a OSC you have to debayer first otherwise you'll be stacking different coloured pixels on top of each other and you'll never get the colour right, and it tends to blur the stars. eg:

star in frame 1
RGRG
GBGB

same star in a later frame with a one pixel drift
GRGR
BGBG

Stack before debayer:
R+G R+G
G+B G+B

[telemarker]

I tend to just align and stack the fits files in DSS which automagically does the debayering then use the resultant tiff file for post processing. In DSS make sure you tell it the bayer filter pattern of the camera.

[telecasterguru]

Thanks for all the info guys.

I think my main problem is focus. Have to work on it some more.

Also have to wait for a field flattener and focal reducer which I am sure will help. It is supposed to be available next month. I might try an Apo reducer which is supposed to work almost as well for RC.

Sorry, but when I said I was having trouble aligning I meant with the mount not the images. I use DSS which is a great program.

I will just have to learn about CCD imaging which is a bit different from DSLR.

Frank

[gbeal]

I never had any luck at all with the Bat Mask, and would suggest you use the inbuilt software assist focusing. Nebulosity has this and it works just fine.
Gary

[Terry B]

This is curious.
I found the Baht mask to work perfectly. I made my own from foam board for about $1. It gives me perfect focus in 1 minute vs mucking around for 10 minutes.

[gbeal]

Then I guess each to his/her own. I prefer the software assisted, or complete auto-focus.
Gary

[Paul Haese]

Frank not a bad starter image but I think you might be just a little too oversampled. Using a reducer will certainly make a difference to your sampling rate. You could use this rate for doing planetary nebula though, especially on the smaller ones.

As for focus I use the bahtinov mask too. I do view it at 200% though. This gives me a very accurate focus. You might find you can use the bahtinov grabber software too. I cannot get it to work with my camera or capture software, but it might work for you.

[telecasterguru]

Paul,

I have used the bat mask many times before and not had trouble. For some reason with this camera I could not get the spikes in a star using the frame and focus images no matter what I did.

I agree that I should use this camera for PN at a long focal length and PN are my main interest at the moment.

I think I will get a QHY9 for other deep space objects.

Frank

[Octane]

Frank,

Chris (Omaroo) takes exposures for several seconds to show up the spikes. When I used the 40D, I would bring the LiveView on the eeePC screen and use the Bahtinov Grabber software over the LiveView image. It was very fast and I could make adjustments in real time, zoomed in at either 100% or 200%.

I have since found that using the Bahtinov Mask and Bahtinov Grabber gives me out of focus stars. I think this is due to some slight chromatic aberration in the ED127. When the Bahtinov Grabber software indicates "perfect" focus, my stars are void of colour and I see a bit of a chromatic halo around the stars. I then adjust the 10:1 focuser out by a smidgeon and I see colour return to the stars and I know I'm in focus. This is most evident on red stars. So, the software gets me to within a hair's width of focus. Still, that's pretty good I reckon.

H