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chara:fringe_offsets [2021/09/20 18:28]
gail_stargazer
chara:fringe_offsets [2021/12/06 15:10]
gail_stargazer
Line 2: Line 2:
  
 The fringe offsets on any given night will depend on the POP configuration and the daily alignment. The table below gives a range of values where the fringes have been found for each cart on multiple nights across different POP configurations. The ranges should at least provide a guide for how far one might need to look to find fringes. The relative offsets between any pair of telescopes can be calculated from the differences between the ranges. The fringe offsets on any given night will depend on the POP configuration and the daily alignment. The table below gives a range of values where the fringes have been found for each cart on multiple nights across different POP configurations. The ranges should at least provide a guide for how far one might need to look to find fringes. The relative offsets between any pair of telescopes can be calculated from the differences between the ranges.
 +
 +A new baseline solution was created on October 18, 2021 and accounts for changes in elevation. The offsets are more stable over the night, but there seems to be some differences between pop configurations. There is a new fringe predictor tool that plots offsets for the last 5 nights based on mircx headers. Log on to spooler@mircx and type "fringe_predictor" to see the mst recent offset vs. hour angle plots for each baseline.
 +
 +S1: -0.2 mm to +1.2 mm\\
 +S2: -0.6 mm to +0.8 mm\\
 +E1: 0.5 mm to +2.0 mm\\
 +E2: -0.2 mm to +1.6 mm\\
 +W1: 1.0 mm to +3.0 mm\\
 +W2: Reference Cart
  
 The offsets on S2 changed after the primary mirror recoating and realignment in September 2021. We are still using the baseline solution created July 29, 2021. The fringe offsets change rapidly with hour angle of the target. Early hour angles tend to have more negative offsets, positive hour angles tend to have more positive offsets. {{:chara:files:baseline_offsets_2021sep17_20.pdf|See plot of cart offset vs. hour angle}}. Fringes during 6T MIRCX observations on 2021 Sep 17 and 20 (W2 as reference cart): The offsets on S2 changed after the primary mirror recoating and realignment in September 2021. We are still using the baseline solution created July 29, 2021. The fringe offsets change rapidly with hour angle of the target. Early hour angles tend to have more negative offsets, positive hour angles tend to have more positive offsets. {{:chara:files:baseline_offsets_2021sep17_20.pdf|See plot of cart offset vs. hour angle}}. Fringes during 6T MIRCX observations on 2021 Sep 17 and 20 (W2 as reference cart):
chara/fringe_offsets.txt ยท Last modified: 2023/08/30 16:57 by gail_stargazer