SA: Tim
SO: None
Others: Hitesh, Charl, Ockert, Chris, Martin, Ted
---------------------
Summary
---------------------
no SALT operations other than hitesh doing a quick mirror alignment to test something. tim and ted worked on FP stuff until 2330 and then tim worked on mass-dimm/timdimm stuff until 0330.
Nightlog 2010-07-24
SA: Tim
SO: None
Others: Hitesh, Charl, Ockert, Ted
---------------------
Summary
---------------------
ted worked on FP stuff most of the day and through the evening. tim assisted in the afternoon and evening. charl gave a tour to the group from university of central lancashire and exercised the structure as part of the exercise. with an assist from hitesh tim opened up and did some starcam observations with the structure and tracker both fixed in position. got just under two hours of data before being forced to close due to humidity at 2040 SAST.
---------------------
Results
---------------------
the behavior of the previous starcam results led me to believe that the non-repeatability probably has something to do with temperature effects. namely, the clear, dry conditions we were experiencing means the sky is very cold and different parts of the structure will couple to that differently depending on how they're shielded by the dome. to test this, we took some data tonight with the structure fixed at an azimuth of 150 degrees and the tracker locked down at (0,0). in this configuration with the dome open we ran a script to take a starcam image once a minute. we were only able to get just shy of 2 hours of data due to high humidity, but even this was enough to show significant drifts in both elevation and azimuth (see attached plots). the drifts amount to 1.1' in elevation and 2.7' in azimuth. we didn't open the louvers or condition the chamber well so this probably exaggerates the effects of temperature variations, but it does show how significant they can be and the results are consistent with what we observed in our previous tests.
No comments:
Post a Comment