20170201

Twilight Tests

Note: Twilight exposures are critical science calibrations for LRS and VIRUS and if possible should be done every night that science data is taken.

twilights with VIRUS with different tracker positions

Purpose: There is some interest in seeing what the long term illumination correction changes look like including what different track positions do to them. The script is "specialtwilight" in /home/mcs/astronomer/bin/. It takes a single argument which is the Observation number.

Procedure:

• Despite of pressures at the start of the night try to get the twilights.
• Setup the guide camera for sky twilight (GC2, 0.1 sec, B filter)
• When you hit the correct flux level (biased to a slight higher value, perhaps 5k) execute the specialtwilight script

On-sky science:

Watch out for the moon brightness. I am not sure that the automatic moon brightness works in htopx so you should set this manually to make sure you don't hit inappropriate targets or miss targets. After the moon sets just turn off the moon brighness.

If you have a choice of targets please skip PSU17-1-002, however, if the moon is up these are perfectly fine targets to observe.

During any thin parts of the night (few targets) please try to get your standards.

When VIRUS targets are available they generally should have priority over regular targets, at least at the same priority.

Watch out for the request telluric standards needed just before or after UT17-1-008!

On-sky engineering:

This should be the lowest priority but could be done when the moon rises or during a hole in the queue (after standards have been taken). The priority of the tests is in the order given below.

WFS1 coordinate transform test

The purpose of the test is to verify that we have the correct directions for all offsets. Note that the WFS1 controls the theta and phi through the TTC fiducial.

• Setup on a star 20 minutes before the center of the track
• Setup guiding and get well centered with WFS1
• Null out any offsets in WFS1 using the hand paddle for focus, theta and phi.
• increase exposure times on the WFS1 to greater than 15 seconds but not saturated.
• make sure the WFS1 loop is started but not activated
• make sure that the TTC is in open loop mode
• make a 2" X sky offset with the hand-paddle, save 5 frames and record the time and offset type in the RA log
• recover position and null any WFS1
• make a 2" Y sky offset, save 5 frames and record the time and offset type in the RA log
• recover position and null any WFS1
• make a 0.25mm focus offset with the hand-paddle, save 5 frames and record the time and offset type in the RA log
• recover position and null any WFS1
• make a 15" theta offset with the hand-paddle, save 5 frames and record the time and offset type in the RA log
• recover position and null any WFS1
• make a 15" phi offset with the hand-paddle, save 5 frames and record the time and offset type in the RA log
• recover position and null any WFS1
• set a new fiducial on the TTC and close the loop
• save 5 frames with the WFS and TTC and record the time in the RA log
• change the fiducial position by 15" in theta -> which means increase the y fidicual position by 27
• save 5 frames with the WFS and TTC and record the time in the RA log
• move the fiducial position back to its original position
• save 5 frames with the WFS and TTC and record the time in the RA log
• change the fiducial position by 15" in phi -> which means increase the x fidicual position by 27
• save 5 frames with the WFS and TTC and record the time in the RA log

Then repeat the entire test for WFS2.

Characterize LRS2-B to LRS2-R offsets

The purpose of this test is to document how well we move from a well setup position on the ACAM for 1 LRS2 position to the other.

• Start a trajectory
• setup on ACAM and one guide probe at the LRS2-B location.
• offset from LRS2-B to LRS2-R using: B2R: syscmd -T 'offset_trajectory(dx_ang=-103, dy_ang=+3, adjust_probes="true")'
  • Guider should stay in Active mode
  • Allow guider to catch the star and drag to the final position
• once the guider has settled to position measure the position on ACAM and report in the RA report.
• have the TO center the object on the LRS2-R and set new guider fiducial.
• offset from LRS2-R to LRS2-B using: R2B: syscmd -T 'offset_trajectory(dx_ang=103, dy_ang=-3, adjust_probes="true")'
  • Guider should stay in Active mode
  • Allow guider to catch the star and drag to the final position
• once the guider has settled to position measure the position on ACAM and report in the RA report.

Repeat this test 5 times, but it can be done in a single trajectory.

• When done please make a summary of the offset results from B->R and from R->B.

Blind setup accuracy

The purpose of this test is to document how well we setup on the ACAM LRS2 position for any given offset star.

• Start a trajectory for a 13 mag star on the LRS2-B using do_shuffle with the latest version of the fplane and cfg files. (matt4)
• Save the do_shuffle fake ACAM image for later analysis.
• setup on ACAM and one guide probe at any blind offset star and record the target position of the setup star.
• save an image and measure and document the position of the star which should be near the LRS2-B position. Here we are using a star close to the IFU to serve as a proxy LRS2 observation. We take only acm images, and we use the star close to the IFU position to measure how a real LRS2 observation would be stup. The idea is to use different steup stars in the acam setup image and see if our IFU-proxy star moves around.
• repeat the last two steps for up to 5 different blind offset stars.

Repeat the test for 3 different trajectories (different Az)

Repeat the test for LRS2-R.

• make a table of: AZ blind offset X blind offset Y LRS2 target X LRS2 target Y
• send out resulting table to het-ops.