ENR CTIO Blanco 4-m 2020-03-09

Time spent engineering with the f/8 guider and COSMOS.  

From Rolo and Omar on the f/8 guider:
We first checked that the stars were falling on the field of the guider detector when the guide probe is at position 0,0. Position 0,0 of the guide probe should match the optical axis of the telescope and we were able to confirm that that was the case. Then we use GMAP to pick guide stars from the patrol field and send them to the TCS to move the guide probe to acquire the selected guide star. That also worked. Then we tested and succeeded in picking stars at different rotator angles as well. Then we focused our efforts on improving the guide star acquisition by calibrating the offset value for centering the acquired guide star on the detector field (without calibration the star falls right at the edge of the detector field). We tried first doing the calibration on the guide probe controller side with no luck, but finally we decided to calibrate the offset on the TCS side by adding the offset to the output of the guide probe guider slew logic. We repeated all of the tests done before the calibration and then we tested that the follow mode was functional as well. That worked fine, so we declared the work done. Omar will refine the tools for managing the calibration values tomorrow to be ready for the rest of the F8 run.

Many thanks to Omar, Rolo, Hernan, Rodrigo, and Alberto for their work on the guider.

For COSMOS, I took a set of spectrophotometric standards using the V4K grating and the blue, center, and red slits.  Toward the end of the night, I moved to an M83 SNR field.  This field was observed by Points in Jan 2019 using Goodman and I wanted to make a comparison between Goodman with the 1200l/mm grating and COSMOS with the V4K grating.  Observations with both instruments used a 0.6" slit.  The acquisition process was more difficult with COSMOS due to the lack of a narrow-band H-alpha filter.  I will compare the results once the data are reduced.