How to calculate HPF's fiber positions on HET
-Incase of any doubt, drop me an email (Joe Ninan)
Scenario 1: Everything from scratch
When: This is when you suspect the HPF's fiber puck inserted in the HET's focal plane has moved with respect to BIB, LRS2 etc..
Things to do:
Measure the cCFB and sCFB positions in in ACAM
Calculate all of the HPF fiber positions in the fplane.txt file
Calculate the offsets in X & Y coordinates for moving from cCFB to science fibers.
Calculate the ACAM pixel coordinates for all the fibers.
Step 1: Measure the cCFB and sCFB positions in ACAM
Use the previous estimate of the ACAM coordaintes to bring the star inside cCFB
Guide the telescope using a guide probe and offset it to bring the star to the center of cCFB. (You cannot guide on cCFB unless the orientation is constrained later)
Once the star is at the center of cCFB of HPF_ACQM, and guiding smoothly on the guide probe. Insert the ACAM and wait for it to stabilise before taking exposure.
Take a few exposures, and then retract the ACAM. Make sure star is still at the center of cCFB
Repeate the procedure of inserting the ACAM, taking images, retreive,reinsert..
Average the centriods to get a good accurate ACAM pixel position of cCFB.
Do the same for sCFB and get its pixel coordinates on ACAM.
Step 2: Calculate all of the HPF fiber positions in the fplane.txt file
Get the latest ACAM pixel positions of BIB, LRS2R, and LRS2B from https://het.as.utexas.edu:8001/trac/WFUCommissioning/wiki/NightOperations/Commissioning/Results
Get the fplane.tx coordinates of BIB, LRS2R, and LRS2B from fplane.txt file
Fits a linear transformation matrix to transform ACAM pixel coordinates to fplane.txt coordinates
Scenario 2: Update the ACAM coordinates after an IHMP take down and IFU install
When: This is when there is only an overall shift to correct after IHMP take down and IFU re-install
Things to do:
Get the old ACAM pixels positions of BIB, LRS2R, and LRS2B
Get the latest ACAM pixel positions of BIB, LRS2R, and LRS2B from https://het.as.utexas.edu:8001/trac/WFUCommissioning/wiki/NightOperations/Commissioning/Results
Fit a linear transformation from the old pixel coordinates to new pixel coordinates
Apply the transformation to old HPF acam pixel positions to obtain new pixel coordinates