Atik Cameras Forum

Support (Please note, this is primarily a user forum, for direct Atik support, please email support@atik-cameras.com) => 3- and 4-Series Cameras => Topic started by: wahee on December 23, 2012, 04:16:53 pm

Title: atik 428ex osc
Post by: wahee on December 23, 2012, 04:16:53 pm

hi

I have just purchased the 428 ex OSC camera

I have got it connected up and was looping shots with a cover over the nosepiece

I noticed this blue line in the image. It getts better when the camers is cooled, but I didn't think it should be there.

I tried a different USB port etc but no change
Any help most appreciated

(https://lh5.googleusercontent.com/-2f-r_3QRLrA/UNctLdqw7bI/AAAAAAAAD-E/6z3iYg7VqI0/s800/atik%20428.jpg)

Title: Re: atik 428ex osc
Post by: bwa on December 23, 2012, 06:56:22 pm

I notice you're using a 1 sec exposure with AutoStretch checked.

1) Try a 1-5 minute exposure and see what the result looks like.

2) Then turn off AutoStretch and reset lower/upper bounds to min/max.  Capture the image and open it in something like Photoshop.  Stretch it and see if the problem still exists.

I have a mono 428Ex.  It has probably the cleanest dark frame I've ever seen.

bwa

Title: Re: atik 428ex osc
Post by: wahee on December 23, 2012, 10:01:59 pm

hi thanks for the reply.

here is a 4 minute dark taken and stretched right up in PS. The issue seems to be much reduced in real world use I guess.

This one is with the cooling on

(https://lh3.googleusercontent.com/-U0b0R3GS8tI/UNd9zpsdhcI/AAAAAAAAD-Y/KuUN3KF4NAk/s1024/dark.png)

Title: Re: atik 428ex osc
Post by: bwa on December 23, 2012, 11:36:21 pm

I believe the problem in your 1 sec sub was the huge stretch applied by the AutoStretch checkbox being checked.  The sub still looks a bit noisy with maybe more hot pixels than I would expect off a Sony sensor but I believe your image was one dark, not a stack of darks?

I've uploaded the 1800sec(30min) master dark off my mono 428Ex created from 20 subs taken at -10C for comparison (stretched to the max. w/ the Curves tool in Photoshop).  Image at:

http://tinyurl.com/bwa428Ex30minMstrDrk

I normally do not use darks in the processing of images off the 428Ex.  I do, however, dither subs to average out sensor "flaws", which are pretty minimal.

bwa

Title: Re: atik 428ex osc
Post by: wahee on December 24, 2012, 12:16:28 am

hi yes it was just one sub. The line is a bit concerning as it is continual.

The camera also was indoors at 26 deg C and the camera just would go down to -3 deg.

I will try to take a stack of darks at a lower temperature and compare

Your dark frame is amazing it shows just how great the camera can be

Title: Re: atik 428ex osc
Post by: bwa on December 24, 2012, 03:28:42 am

Yes, I've noticed you can only get about 30 degrees of cooling out of the 428Ex peltier; a problem if you're shooting in particularly warm climates. 

I have never run into this problem... it is -25C outside here at present.  Just in time to fire up my mount and get imaging!

bwa

Title: Re: atik 428ex osc
Post by: wahee on January 12, 2013, 12:05:00 am

yes it doesn't drop as low as some other cameras I have used.
It's a bit of  learning curve after using the DSLR for so long
I managed to get this shot of M42, so I think the camera is performing ok in real world use

(http://homepage.ntlworld.com/quad303/astroimages/images/atik%20m42.png)