Resolved Guide Camera Problems - won't focus/black frames

Have STT-8300 with self-guiding filter wheel 8 position. The guide camera went crazy last night. Got images with large out-of-focus stars, main camera in focus. Turned on camera taking continuos 1-second images and watched the monitor while I adjusted the guider focuser. Nothing changed no matter what I did! Image looked the same. Even tried focusing the telescope, no change, like this one image was in the buffer and wouldn't clear. Took the camera off the scope and watched the guider pick off mirror, which I could adjust up and down fine. Shutter looked like it was working, but now all the images were black. What the hey? Please advise. Already had this camera in the shop twice for various problems, hope this is one I can fix!

Wayne Hixson

 

6.13. I haven't tried it, no astronomy lately due to weather.

 

Hello,

I also own an STT-8300M camera with 8-position filter wheel. A few days ago, I moved the camera to a different telescope, and upgraded Maxim DL to 6.13. The main camera has been carefully and accurately focused. I have spent 2 nights trying to find a guide star with the internal guide camera, and can find nothing to focus, regardless of the position of the guide scope or the focus setting. I've even set the exposure up to 10 seconds, hoping I would discover something on which to focus. I now realize that the images that I'm seeing are not like a typical guider image, but more like a bias or dark image - a uniform grey and white screen of noise.

Does my issue sound like the same issue as Wayne's, or might I be experiencing something else? I see that this is a bug in 6.13, but is there a fix that I can download if this is the same problem, or some other remedy other than reverting back to an earlier version? Does anyone have a permanent solution? I would appreciate any advice. Thank you.

Bob H.

 

Hi Doug,

Thanks. I'll look into that tonight. By the way, this has been a fantastic camera, trouble-free for 2 years, and I use it every clear night. I appreciate your support.

Bob H.

 

Hi Doug,

I couldn't find where to change it to "External", but the guidescope was working fine when I turned the camera on tonight. However, after slewing to a star to focus, and slewing back, I was once again getting the "dark frame" image when I exposed with the guider. Please tell me where to find the "External" setting. I have attached a shot of the guider image that I am getting. Thank you.

Bob H.

 

Hi Tim,

Thank you. I have changed it to External. Is this a work-around of some kind, since the manual states "Select the Internal setting to use the guide chip that is built in to the main camera body. Select External Remote to use a separate "guide head". This camera is an STT-8300M with the guide chip built in. Regardless, if it works I'll be pleased, but I am curious why I set it contrary to the manual instructions. By the way, just so you can understand what was happening, the guide chip was giving me only images that I would call "darks". The next night, it was giving me guide stars. I calibrated and then tested the tracking, which worked fine. When I slewed to a star to refocus and returned to my target, I was no longer getting images of the sky with the guider. I shut down several times, but this did not fix it. I look forward to testing this again tonight.

All the best,

Bob H.

 

Thanks, Doug. I never understood that. Bob H.

 

Hi Doug and Tim,

Thank you both for your help. I have only managed to get the guide scope for the STT-8300M camera to give me an image of stars twice in the past week, even with it set to "External". And when I would slew to a star to focus and slew back, the guider would no long give me a view of the sky, but what I would call a Dark or Bias image. I had the Autoguider output set to Ascom Direct, and suddenly that stopped working, giving me the message "Could not initialize guider output. Please check guider settings". This setting had been working. I switched Autoguider Output to Telescope, and once again the guider started working, but continued to give me Dark images.

Up until now, this has been a fantastic camera, but the transition to use it with another scope has been difficult. I'm not suggesting that I'm not at least partially responsible for the problem that I'm having, but I do need help resolving it. Should I send the camera back for inspection due to this being a mechanical issue, or is this likely a programming issue that can be resolved remotely? I'm sure there is a solution, perhaps even an easy one. I could send you screen shots of whatever you feel might help. What is your advice? I have attached a screen shot of the guider settings. Thank you.

Bob H.

 

Hi All,

This issue has now been resolved. I called Bill Lynch of the SBIG repair department and described all of the testing and experimenting that I had done in an attempt to isolate the problem. He felt that I had eliminated everything except possibly a power issue. I have been running this camera from a 12v source, and it seems that either there is a subtle problem with the power cable or with the power supply. I connected the camera with the original a/c power cord and the guide camera once again works. I don't yet know specifically which item caused this issue, but the problem has now been greatly narrowed down. It seems that the cooler, even when using only perhaps 25% of maximum power, was preventing the guide camera from getting enough power to operate. Thanks to everyone for helping to resolve this issue.

Bob H.

 

Does that brick do more than convert to 12v? I have been using power pole connectors.

 

Hi Doug,

Thank you again. I had switched to a smaller power supply for convenience, which was obviously a mistake. I will correct that immediately.

Bob H.

 

Think of it this way: Would the 12v supply for the CCD be able to start your car? Why not?

 

Hi Bob,

Is that a rhetorical question? I'm not sure. All I need is a power supply that will start a camera, not a power supply that will start a car. I was using a 13.8-volt 5-amp regulated power supply from Astro-Physics, but have now switched to their 15-volt 12-amp regulated power supply. All works fine.

BobH.

 

Ha ha sorry, in retrospect it seems a bit snarky.I apologize. The idea was to point out that the PS has to be able to supply the required voltage while having the required full current pulled from it. If the PS is too weak, pulling "too much" current will drag down the voltage and cause weird problems or malfunctions.