Arduino Shutter Control is Implemented

I have gotten my replacement for the Foster Systems shutter control operational. Go to this page for more information.

Basically, I have had too many problems dealing with Foster’s shutter control. The Rotation system works well enough, but I have constantly had problems with the shutter system. In particular, the software always had problems (the hardware seems to be robust).

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Another Darkness Tool

I borrowed the SQM-L meter from NOAO again to try a new thing. As per Sky & Telescope, a new iPhone6 app allows me to use the iPhone as an SQM meter! So, I wanted to a) compare readings from the two devices, and b) calibrate the iPhone as needed.

I ran seven sets of 10 readings, 3 on the SQM-L and 4 on the iPhone6. The 42% moon was still in the West and there were some clouds. Temperature was dropping rapidly.

SQM-iphoneGraphConclusions:

a) the SQM-L has better reproducibility. Its readings are within 0.1 units most of the time (my readings are about 20).

b) the iPhone gets the same readings but with greater variability, perhaps +/- 0.3 units. Comparing the 10 reading averages shows the iPhone statistically the same as the SQM-L. That’s good, since I don’t know where I would put my calibration value in the app. The app provides 2 corrections, one for readings less than 20 and one for readings over 20. My readings were right around 20, about half just under 20 and half just over:)

The following night when the moon went down, the sky was “pretty clear” (it had been cloudy earlier).

SQM-L showed 20.51 (5 point average, throwing out the first few) = Bortle 5.82

iPhone6 showed 20.42 = Bortle 5.76

I will try again when the sky is definitely clear.

Maxim hangs STF8300

I have been having an irregular problem where ACP imaging would fail when Maxim gets hung on reading the camera. I start an imaging run and it fails after several images.

Symptoms:
– The cooling on the camera reports as being off. When the camera is restarted, it often gives a Filter Wheel err 7, or Maxim crashes.
– The exposing tab says “Reading”. Guiding appears to be continuing.
– Sometimes Maxim gets a filter wheel error 7.

I set up some tests, using only Maxim and the camera (no FocusMax, ACP, SkyX) running sets of 40-50 exposures and found that
a) the problem occurs if I guide on the camera simulator rather than STi.
b) the problem occurs if I have no guiding.
c) the problem does NOT occur if the exposures are 5 min or less. The original problem occurred with 30 minute exposures; it still occurs with 10 minutes.

Found that the camera drivers are out of date again via SbigDriverChecker. I updated the windows drivers, and also updated the camera firmware.

Initial test indicates that the problem has gone away; will need to keep an eye on this.

I also found a scary web post indicating there is a setting in the Power Settings tab which causes Windows to turn off power to a USB port if it hasn’t been used for a few minutes (unclear how many). I will turn this setting off, by default it is on.

Update: turned off the power setting, started to run a series of Darks. Keeps failing, similar to the previous problems. However, slight difference is it indicates “300 of 300” in the progress bar rather than “Reading”. So, will have to keep looking into this.:(

Update: well, it appears that the problem is due to a slightly loose USB cable. I went out and re-plugged in the cable on both ends, and it might have been slightly loose on the computer end. After that, a couple of tests worked OK. Crossing my fingers…