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chara:fringe_offsets [2021/12/06 15:10]
gail_stargazer
chara:fringe_offsets [2022/04/15 01:53]
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 2022Mar21 and has been in use since 2022Apr03.
 +
 +S1: -2.1 mm to 1.5 mm\\
 +S2: -0.8 mm to +0.6 mm\\
 +E1: +0.1 mm to +1.5 mm\\
 +E2: -0.1 mm to +3.5 mm\\
 +W1: +1.1 mm to +2.9 mm\\
 +W2: Reference Cart
 +
 +{{:chara:files:baseline_offsets_2022apr_mix_new_old.pdf|See comparison of the old and new solutions}}.
 +
 +Starting in 2022, it seems the baseline solution has drifted, and the offsets are again trending negative with increasing hour angle. Here are the ranges of recent offsets from March 2022 (look on the positive side of these ranges for early (-) hour angles and toward the negative side for late (+) hour angles):
 +
 +S1: -0.5 mm to 3.8 mm\\
 +S2: -1.5 mm to +2.6 mm\\
 +E1: +1.5 mm to +4.4 mm\\
 +E2: -3.0 mm to +4.0 mm\\
 +W1: -0.5 mm to +4.5 mm\\
 +W2: Reference Cart
 +
 +(hour angle +3 hr on negative side, hour angle -2 hr on positive side)
  
 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. 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.
chara/fringe_offsets.txt ยท Last modified: 2023/08/30 16:57 by gail_stargazer