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- Transfer code works. The images are written to the internal disk and then transferred to the external disk.
- Sources are consistent through 22:45 Chile time
- The camera is moving to the left with a rate of 2 pixels for 500 frames, this was 488
- Actually no turning left, the images started moving right, this is 1276
- We may see huge differential image motion. Or it may cancel out in the COM frame.
- We were taking 5 second exposures, from 11 until 322.
- Started 1, 10, 30 second exposures with 323
- Started 1, 5, 10, 30 second exposures with 326
- Frame 2110, still all sources detected.
- Time 23:33, rotating the dome and taking pictures with the best exposure. Planning to take an additional hour of data after this.
- 23:48 dome opened up more in addition to rotation.
- 23:50, tried 3072, focus gone, going to run back.
- Went up to dome and refocused. New data is in observe-readjust folder
- We find decent sources but it looks like we have a significant shift to left. This time for real.
- Will start taking flats at 1AM.
- The files locations got fixed again. No left shift.
Flat file trials:
Took flat files with dome closed to see the background light. Here is the summary table for the night of 12/13/22:
Exposure ID Exposure Time (s) filter AT azimuth AT elevation flash (y/n) ND filter computer screen status count 435 60 none 270 20 n 1,50 all screens off 4 436 60 none 270 20 y 1,50 all screens off 4 437 60 none 215 20 n 1,50 all screens off 438 60 none 215 20 y 1,50 all screens off 439 60 none 315 20 n 1,50 all screens off 440 60 none 315 20 y 1,50 all screens off 441 60 none 270 50 n 1,50 all screens off 442 60 none 215 50 y 1,50 all screens off 443 60 none 270 50 n 1,50 all screens off 444 60 none 270 50 y 1,50 all screens off 445 60 none 315 50 n 1,50 all screens off 446 60 none 315 50 y 1,50 all screens off 447 60 none 215 50 n 1,50 all screens off 448 60 none 215 50 y 1,50 all screens off We were only able to check the count of the first two images, they were both approximately 4. The absolute difference was negligible, Tiago suggested dividing the flash pictures by non flash pictures.
From Stubbs:
Ok sounds like a partial success. I think the key think is to get a good dome-closed vs. dome-open comparison.
I don't understand the longer exposures. Is that with a single flash per image? If so then all the longer images would seem to do is add to the background and not the signal. Or are you running with constant light source?
I can certainly believe that dome rotation shakes things- During most image the dome is not rotating.
The focus change could well be due to temperature change of the lens. I can't remember if there is an f-stop ring on that lens or not... I think not. The depth of focus will increase if you make a smaller aperture in front of the lens. There is heavy duty Aluminum foil in the cardboard fan box at the base of the pier. You could try making a snout with a 1 inch off-axis hole and see if that (with reducing ND filter) helps with focus.
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