Checklist for technical nights preceding science observing run

Special Projects

  1. Fix the Z22 Zero Point for LBC-Blue. On 24 October 2009 we worked on this and think that it should be changed by -170 nm from 2.3 to about 1.5, see But this was not tested, and with this offset, data were not in focus. A change in Z22 Zero Point would require changes also in Z11 and in focus Z4. We need to determine these and test them. It seemed like a -0.06 mm focus shift was needed, but needs to be tested? (what is the approach we should take here?)
  2. Fine-tune the matrix in lbcfpia.cfg.
  3. Insure past problems with offsets, timing are gone. Create one or two science OBs to check this.
    • offsets absolute and not relative
    • rotator position set by first image
    • first science image offset correctly (try an OB with an initial offset from base position)
    • Blue Master, Red Slave OK?

Collimation and Pointing:

  1. Iterate on collimation and pointing:
    1. Obtain collimation data, fit model and implement.
      1. run the OB, RB_rVfastextra, at a range of elevations. Ask the telescope operator to slew. When the pupil is well collimated, note the filename. Make two lists, one for each side, of the names of these files with well-collimated pupils, e.g. bluecollimlist and redcollimlist
      2. For these files, run hselect to extract the mirror position, elevation and temperature filename: hsel @bluecollimlist mirrorx,mirrory,mirrorz,mirrorrx,mirrorry,telalt,lbttemp > bluecollimdata. There is an IRAF script, which takes as input the list of fits files to be used for the collimation table and outputs the information, ready for input to the IDL fitting routine. The script adds 0.8mm to the mirrorZ values and it converts telescope elevation to decimal degrees. To run the script, define it as a task by giving the full pathname to the script file, i.e. at the IRAF prompt, type task pcollim = /path/to/ It requires as input the name of the list of files with well-collimated pupils and an output filename, e.g. pcollim @bluecollimlist bluecollimdata.
      3. Run the idl procedure, (in /home/lbcobs/Collimation/new/), with the syntax mkcoll_lbc, "bluecollimdata". This will output a file called Collimation_lbc.dat which contains quadratic fits to X,Y,Z,RX,RY as functions of elevation and a set of plots.
      4. Edit the filename to be more descriptive (e.g. SXcollim_yymmdd.dat or DXcollim_yymmdd.dat).
      5. In the five lines around 0 degrees elevation (from +/- 0.2 degrees elevation), if there are any X,Y,Z values >2.0mm or <-2.0mm, replace these by 2.0 or -2.0 and if there are any RX or RY values >50 or <50 , replace these with 50. This prevents the mirror from bumping the static supports when parked at horizon.
      6. The following four steps are from the Commissioning/CollimationModel wiki. Move the new table into the right place/name where PSF will find it. As of 16-Apr-2008, the file with an appropriately coded name SXPMLBCCollimation.dat or DXPMLBCCollimation.dat goes in /home/telescope/TCS/Configuration/PSF/new/.
      7. Press the initialize button on PSF to load the new table. Be sure that Active Optics corrections are cleared and Global Offsets are cleared (green numbers are zero).
      8. Then it should work. Note that a small change in temperature can result in a different initial focus. The new table should be good enough for LBCFPIA to run without manual intervention. Verify that the new table isn't causing the mirror cell to "saturate" its position (X,Y,Z more than +-2.6 mm, RX,RY more than +-100 arcsec) at high or low elevations.
      9. Confirm that the new table gives correct results.
    2. Off-line:
      • compare to old collimation models
      • note where limits are hit (elev > 80, Y limit of SX is touched)
    3. Obtain pointing data, make azimuth correction and implement.

Check or refine calibrations if necessary:

  1. Astrometry - obtain one astrometric field. OBs are in /home/lbcobs/REDCOMMISSIONING/ASTROMETRIC_STD/
  2. Throughput - obtain one standard star field if photometric. OBs are in Calib_OBs package, in STANDARDS directory.
  3. Filter focus offsets - red I and R highest priority, next all other red.
  4. Investigate shifts in Y collimation.
  5. Check temperature coefficient... the points that were discrepant in the last collimation model were those 3 that were obtained last, after the nominal collimation run, and at a lower temperature.

Investigate recently uncovered or ongoing problems with LBC or telescope:

  • Focus changes in DX/Red: issues 1214 and 1245.
  • Blue guiding - mirror jumps. Issue 1148 and 1035.
  • Red rotator - after powering on, does not stop? Reported by Vincenzo during INAF run at beginning of April.
  • Red filter wheel #1 - problems reaching position. Wheel #1 contains Red Bessel filters & Y-FAN

Implement tools to aid observers and LBTO staff

  1. Simple scripts to list relevant header information for images taken that night.

Check stability of cameras:

  1. Obtain biases and a dark. OBs for this are in the Calib_OBs package: Calib_OBs/BIASDARK and are 25Bias_Bino.ob and 2Darks_Bino.ob.
    1. Check bias stability and dark count rate
  2. Obtain flat fields (ask Vincenzo which filters and PAs are most needed). OBs are in Calib_OBs/SKYFLATS/
  3. Calculate gain from flats and biases. One way (Howell, Handbook of CCD Astronomy): gain = [(avg(f1)+avg(f2)) - (avg(b1)+avg(b2))]/[sig2(f1-f2) - sig2(b1-b2)] and readnoise = gain x sig(b1-b2)/sqrt(2)

OlgaKuhn - 17 Apr 2008
Topic revision: r9 - 07 Sep 2012, OlgaKuhn
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