Etalon Engineering Run 2014Jun
This CHARA run is for installing and testing the Etalon.
by John Monnier
I arrived on 2014Jun07 with the hardware. I discovered a small clearance issue -- the edge of the mount clipped V6. see image below
Media:etalon_clearance_problem.jpg
Laszlo kindly trimmed off the extra hardware and moved the mounting points over 3 inches. Now it is fine.
Keith Johnson joined me on Jun 11 (I had a Jun 9 keck run to attend to). We did a number of tests and discovered the chara beams were heading down at about 0.5 degree angle -- we had shim the mount to account for this so that the etalons were near-normal. All of the etalons are normal to beam within about 18" or so -- usually better. We measured by putting in a target with hole and looking for the spot upon reflection on a target. We used steel shims from Laszlo.
We did some tests in the lab to confirm that the system was working as expected. on UT2014Jun15 we aligned MIRC with the PRISM and used B1B2 with etalons 2.000 <-> 2.006 (see engineering logs) and the data seemed to show good correspondence with expectations. We also tried 2.000 <-> 2.012 for B1 and B2, but we did not have adequate spectral resolution to see the phase modulation.
Next on 2014Jun16 we aligned using the R150 GRISM. there was a clearance issue and so couldn't simply 'move' the spectrum into the correct quadrant. So we had to the 'flip quadrant function.' Our final setup was: 48 252 100 2 4 500 500 which gave frame times of 13ms (Ok). We repeated the same experiment as previous day using a dx=6mu and dx=12mu etalon along with calibrations. For fun we also found the secondary fringe packets -- by tuning the retro by 2mm X 1.46 we found fringes with extra dispersion .. also for 4mm X 1.46
I analyzed the 2014Jun16 data carefully and found good correspondence with theory.. see:
Next we came up with an observing strategy for the run.
mu boo (cal: gam her). mu boo was a target in PHASES with no astrometric motion. Good test target.
v819 Her (cal: gam lyr). v819 her is a perfect test target from Mutterspaugh thesis. bright, up in june, 100mu-as motion with 4.4 day period, separation <~100mas.
kap peg (cal: sig Cyg). kap peg is another great test from MUtterspaugh thesis. separation is larger 100-250mas (150mas for our current run). astrometric mtion of B is 1.0 mas motion over 6 day period.
