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chara:fringe_offsets

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Fringe Offsets

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 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. See plot of cart offset vs. hour angle. Fringes during 6T MIRCX observations on 2021 Sep 17 and 20 (W2 as reference cart):

S1: -2.5 mm to +1.0 mm
S2: -1.2 mm to +2.4 mm
E1: -2.4 mm to +1.0 mm
E2: -2.8 mm to +1.2 mm
W1: -3.5 mm to +0.8 mm
W2: Reference Cart

A new baseline solution was created on July 29, 2021. The fringe offsets continue to change rapidly over time depending on hour angle. See plot of cart offset vs. hour angle. Fringe offsets during 6T MIRCX observations on 2021 Jul 29, Aug, 02, Aug 06 (W2 as reference cart):

S1: -2.5 mm to +1.0 mm
S2: -2.0 mm to +0.6 mm
E1: -1.8 mm to +0.9 mm
E2: -1.5 mm to +1.0 mm
W1: -1.5 mm to +0.8 mm
W2: Reference Cart

Fringe offsets during 6T MIRCX observations in 2021 Mar-Apr (W2 as reference cart): For the current baseline solution, the fringe offsets change rapidly depending on hour angle. See plot of cart offset vs. hour angle.

S1: -2.0 mm to +2.0 mm
S2: -2.0 mm to +2.0 mm
E1: +0.0 mm to +3.0 mm
E2: +0.0 mm to +3.0 mm
W1: -1.5 mm to +2.0 mm
W2: Reference Cart

Fringe offsets during 6T MIRCX observations in 2020 June (W2 as reference cart):

S1: -0.7 mm to +1.1 mm
S2: -0.2 mm to +0.6 mm
E1: +0.2 mm to +0.8 mm
E2: +0.6 mm to +1.6 mm
W1: +0.8 mm to +1.3 mm
W2: Reference Cart

Fringe offsets during 6T MIRCX observations in 2019 July-August (W2 as reference cart):

S1: -1.3 mm to +0.2 mm
S2: -1.1 mm to +0.2 mm
E1: -2.0 mm to +0.5 mm
E2: -0.8 mm to +0.7 mm
W1: -0.6 mm to +0.2 mm
W2: Reference Cart

Fringe offsets during 6T MIRCX observations in 2019 July (W2 as reference cart):

S1: -0.8 mm to +0.2 mm
S2: -0.6 mm to +0.2 mm
E1: -1.1 mm to +0.5 mm
E2: -0.4 mm to +0.6 mm
W1: -0.2 mm to +0.2 mm
W2: Reference Cart

NOTE: Theo installed a new baseline solution on 2019Jun26. This is based on Aaron's most recent file merged with new numbers for beam off sets and internal airpaths as measured by Judit and Theo in the lab.

Fringe offsets during 6T MIRCX observations on 2019 May 31 - June 2 (W2 as reference cart):

S1: -2.6 mm to -1.5 mm
S2: -2.6 mm to -1.7 mm
E1: +1.9 mm to +3.4 mm
E2: -2.5 mm to -1.0 mm
W1: +0.6 mm to +1.8 mm
W2: Reference Cart

NOTE: Theo installed a new baseline solution on 2019May09.

NOTE: Theo installed a new baseline solution on 2019Apr12.

Fringe offsets during 6T MIRCX observations on 2019 Apr 2+9 (W2 as reference cart):

S1: +3.0 mm to +4.4 mm
S2: +0.3 mm to +0.5 mm
E1: -0.4 mm to -2.3 mm
E2: +5.9 mm to +6.8 mm
W1: +6.3 mm to +8.9 mm
W2: Reference Cart

NOTE: Theo installed a new baseline solution on 2019Feb20.

Fringe offsets during 6T MIRCX observations after Phase 2 upgrades in 2018 September (W2 as reference cart):

S1: +4.3 mm to +6.5 mm
S2: +3.0 mm to +5.0 mm
E1: -3.0 mm to -0.7 mm
E2: +6.5 mm to +9.0 mm
W1: +6.0 mm to +7.5 mm
W2: Reference Cart

Fringe offsets during 6T MIRC observations on 2018 Mar 29 (W2 as reference cart):

W1: -0.3 mm to +1.4 mm
S2: +3.3 mm to +4.4 mm
S1: +1.4 mm to +2.1 mm
E1: +3.7 mm to +4.3 mm
E2: +3.3 mm to +4.2 mm
W2: Reference Cart

NOTE: Theo installed a new baseline solution on 2018 Mar 22.

Fringe offsets during 6T MIRC observations on 2017 Oct 26-27 (W2 as reference cart):

W1: -4.0 mm to 2.7 mm
S2: -0.3 mm to +0.6 mm
S1: -2.0 mm to +0.4 mm
E1: -3.0 mm to +2.4 mm
E2: -2.0 mm to +1.5 mm
W2: Reference Cart

NOTE: There might have been another baseline solution applied in August.

Fringe offsets during 6T MIRC observations on 2017 July 9-10 (W2 as reference cart):

W1: +5.6 mm
S2: +1.0 mm to +3.0 mm
S1: +0.8 mm to +3.1 mm
E1: +2.5 mm to +5.0 mm
E2: +1.0 mm to +3.1 mm
W2: Reference Cart

Fringes offsets during CLIMB fringe searching on 2017 July 4 (W2 as reference):
E1: -1450 um to -1600 um
E2: -1450 um to -1900 um
S1: +2900 um to +3230 um
S2: +3380 um to +3650 um
W1: -500 um to -750 um
W2: Reference Cart

NOTE: Theo ran a new baseline solution on 2017 June 08.

Fringe offsets during 6T MIRC observations on 2017 March 18 (W2 as reference cart):

W1: -15.9 mm to -18.4 mm
S2: 0.0 mm to -1.6 mm
S1: +0.5 mm to +1.1 mm (S1 fringe extrapolated from relative S1-S2 offset in previous configuration)
E1: +2.0 mm to +4.8 mm
E2: +3.3 mm to +6.5 mm
W2: Reference Cart

NOTE: AO optics were installed in all remaining beams during 2017 Jan-Mar.

Fringe offsets during 6T MIRC observations on 2016 June 18 - 2016 July 17 (W2 as reference cart):

W1: -3.4 mm to +1.6 mm
S2: +0.8 mm to +5.3 mm
S1: +1.0 mm to +5.9 mm
E1: +2.4 mm to +6.6 mm
E2: +1.4 mm to +5.3 mm
W2: Reference Cart

chara/fringe_offsets.1632176305.txt.gz · Last modified: 2021/09/20 18:18 by gail_stargazer