Friday, December 27, 2013

Temperature Compensation

I noticed that the TOA scope shrinks quite a lot during the night when it gets colder. When I focus my scope first thing in the evening, it has to move almost 100 steps(!!) to regain focus (the last position was the focus point at the end of the previous night).

So, I used the TEMPer device to measure temperature and then the Bahtinov grabber do determine exactly the focus point:
1. Evening - 11.98 degrees - 29296
2. 1am - 6.91 degrees - 29224

That means I have to adjust 14 steps for each degree!

I entered this in SGPro. Next night, I checked but it didn't look as if SGPro adjusts the focuser (unless I run autofocus again). I checked in the log file and found a lot of lines like this:

[12/27/2013 4:34:31 AM] [DEBUG] [Sequence Thread] Temperature compensation: Adjusting for 0.0 degrees (end: 100.0; end: 100.0; coefficient: 14) for 0.0 steps...

Seems as if SGPro is not using the TEMPer device for compensation but the built-in Robofocus temperature (which always returns 100 degrees!) I asked on the mainsequencesoftware mailing list and was told that this wasn't implemented so far, but that the code is ready and will be in one of the next updates!

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Checked the fix, but it seems as if the 100 degrees still come in from somewhere. Waiting for the next fix.

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Release 2.3.1 seemed to address this! Worked perfectly the first night. But next night, the temperature was shown as NA. After some trial and error, I found out that I first have to disable this setting (Tools->Options->Other Equipment Options->Use a TEMPerHUM device) and then re-enable it. Then the temperature would be read properly from the TEMPerHUM device.