Seeing index: OK (3)
Transparency: Average (3)

    Integration time:
    * OSC 33 X 120s (66m)
    * Total: 1h06m

This evening was unexpectedly clear though with a thin layer of high, semi-tramsparent cloud which affected guiding and visibility. Around half the gathered frames were discarded. The clouds got thicker around 1 am so I closed the observatory roof and left the calibration frames for the morning. As has been the case recently, calibration frames have been very problematic but I did finally resolve two outstanding issues: