SC-4C not picking up star when tracking

I have an SC-4C I use for guiding my 47-10. I can run the calibration step under the Guide tab in the Camera Control window in Maxim DL to calibrate the guider, which works properly, but when I select "Track", the guider is not able to track. The SNR of the star listed in the Camera Control window will be very low, like 0 or less than 1, despite the star in the Autoguider Image window appearing quite clearly. If I disconnect both the 47-10 and the SC-4C cameras on the Camera Control window, then reconnect, redo the calibration, then the guider is able to track. While this eventually works, it's rather inconvenient. For reference, the star I'm using for tracking tonight was initially reading an SNR of 0, but after doing the reset, it's at an SNR of 40.

Has this been seen before? I am running Maxim DL 7.1.4.

 

Other strange behavior: I'm doing a long set of exposures, using a 5 second exposure for guiding. The guide star faded from view after about two hours of observing. I stopped tracking, and did a single 5 second exposure on the Guide tab. The image was completely blank, with every pixel at 0 counts. I switched to a 4 second exposure and a 6 second exposure, and both of those were able to show stars. I've set it to tracking using 6 second exposures, and that seems to be working well for now.

 

Thanks, I will try that.

Also, the same behavior happened with the 6 second exposures. After maybe 2 hours the images went dark and nothing was showing up. 4 second and 7 second exposures showed stars, but 5 and 6 second exposures were blank. Disconnecting and reconnecting the cameras via Maxim DL was able to fix this, and the exposures were again seeing the sky. I'm not sure if this helps, but I'm attaching a 5 second exposure before (*blank.fit) and after (*restart.fits) restarting the camera. It's blank prior to the restart, and normal after the restart.

 

I've updated the software to 7.2.2 but unfortunately I'm still running into the issue of Maxim not recognizing the autoguider star. Maxim was reading a SNR of 0, though the star was visible in the image and it could properly calibrate. It took about 30 minutes of rebooting Maxim for it to properly read the star. Once it did recognize it, it was reading an SNR of ~45.

I also ran into a separate issue with the calibration. While the star would move left-right and up-down during calibration, the software was not reading the up-down motion properly. It correctly drew a line connecting the star's before/after position when moving left-right, but the up-down motion was off by 45 degrees. This was fixed after restarting Maxim.

I haven't run into the disappearing star issue so far.

 

This is a bit of a mess, but I'll include everything here to see if it helps you out, in the guider.zip file. I'm including the Maxim DL log as well. We did some work with collimating the telescope up until 00:52 when we started to use the guider. We again ran into the issue of the guider reading a S/N of 0 and the 45 degree error. The S/N of 0 errors seem to correlate to the "Warning - Error getting guider imageError" messages that appear in the logs. Screenshots of the 45 degree error are attached. Unfortunately in the process of trying to fix this and closing/reopening Maxim DL the Record Tracking Images seemed to have been switched off, so we don't have a record of most of our images.

We also ran into the issue of the guide star slowly fading from view (sadly, no images as mentioned above it was not saving them). In trying to fix this, we adjusted the guider exposure time (around 05:05), which allowed us to see the star, but we again ran into the issue of reading a low S/N and it couldn't guide. We again tried closing/reopening Maxim DL, which did fix it, but in another unfortunate set of events it seemed to overwrite the Tracker.log file so we don't have a full log of the night. However, when I did look at the Tracker.log file during the night, I could clearly see the column that reads "Bright" getting smaller and smaller as the guide star was disappearing. I think it got to like 40, when it started around 150. I'm assuming that's related to the brightness of the guide star.

Two other things to note:
When the guide star was fading from view, the telescope was still able to track well, in fact there was no real noticeable difference between guiding with a visible star, and guiding with the faded star. I'm confused by this as there was virtually no signal from the guider star, as seen in the images.
We were using 5 second exposures for our guider, where the guide star eventually faded. There is an option under the Guider tab to clear the saved darks used for auto-calibration. When I selected that option and took another 5 second auto-calibrated exposure, the image appeared as normal and was not faded. This leads me to believe this is not a shutter operation error, but a software issue. It's like the dark frame itself is being altered somehow. Is there a way to see the dark used for auto-calibration? I could not find them in the GuideCal folder.

If we get another observing opportunity I will try to get another more complete set of data.

 

We have a 40 cm Ritchey-Chretien f/8 telescope with a German equatorial mount. There is no focuser, instead the secondary mirror adjusts as needed. We have a 2 inch draw tube. We have a guider, filter wheel with 1.25" filters, and a CCD 47-10 camera.

 

Ok we'll give that a shot. Is there a way for us to see the auto-dark that's being used for calibration? I did not see it under the Cal files.

 

I set the focal length in the program (I had it set for the main camera, but not the guider!), and it was able to calibrate and track properly on the first try, so hopefully that fixed it. We picked a fairly bright star to track on so we did not see it fade from view like before, but I did see the background counts go to 0 through the night. If the star were fainter I suspect it may have faded again, but can't say for certain.

I have the data saved but haven't had a chance to collate it all. I'll update if I get the data together, or if it happens again. I should be able to get an observation in this Wednesday.

 

I think I figured the disappearing star issue - there is some light leaking through the shutter on the guider when taking the initial dark. At the end of a recent observing run I took a single exposure using the guider with the Expose option under the guider tab. That image is attached as guider_1.fit. It is using an auto-calibration dark that was taken at the start of the night. Right after that image was taken, I cleared the saved dark and took another image with the Expose option, which took a new auto-calibration dark, and produced guider_2.fit. The background is noticeably bright in the second image, as it is not being subtracted off as much as it was when using the dark at the beginning of the night.

So if that issue comes up again I should be able to solve it by clearing the saved dark and doing another one.

 

I didn't save any darks, I didn't think about the issue until the end of the night. I'll try to get some next time.

 

I don't think the shutter is sticking. I'm attaching a set of zip file of images of a test run alternating light and darks as requested.

I'm also including a dark taken at the start of the night (AG_start.fit) and at the end of the night (AG_end.fit). The median counts in the dark at the end of the night are lower by about 100.