Several problems during the night.
1) Before opening for the night, we noticed that some of our short exposure calibration data were ramped. We eventually saw that the dewar had warmed. The conclusion was that the dewar was not completely filled previously, allowing it to warm. We checked the vacuum pressure and it was OK. We refilled the dewar with LN2 and allowed time for the detector to cool. We probably lost an hour on that.
2) Have noticed a drift in the guiding during exposures. I have not completed the analysis of all of the data, but it looks like the telescope may drift by about 6pix EW and 8pix NS during a 20min period. An example of this occurred from images 20159 - 20165. These two images were acquisition images with 4x300s spectra being taken between. I noticed a high peak for the first spectrum and gradually saw the peak decrease of the course of the exposure sequence.The final acuisition image showed the object 8pix N of its starting position. The slit width was only 3pix wide.
3) Focus tool in COSMOS interface does not work. We had to manually focus the telescope by hand. The Telescope focus keyword is not in the FITS header, further complicating matters.
As a result of this, we were able to get spectra of Hamuy spectrophotometric standards, but the data are of dubious value as the stars were drifting off the slit. We will continue with this effort tomorrow.
| Total Times | Time Observed | Time Engineering | Time lost technical | Time lost weather | Time lost other | Total Program Time |
|---|---|---|---|---|---|---|
| 2014-04-11 | 9.5 | 0.0 | 1.0 | 0.0 | 0.0 | 10.5 |
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We need to add COSMOS to the drop down menu of instruments for night reports.