16326

The COS Target Acquisition (TA) monitor is divided into two pieces comma NUV and FUV. This program is the FUV portion and is designed specifically for FUV LP4. FUV LP4 uses NUM_POS > 1 PEAKXDs for cross-dispersion TA. All previous LPs used NUM_POS=1 PEAKXDs. The NUM_POS=1 PEAKXDs required the routine monitoring of the grating-dependent WCA-to-PSA offsets. The NUM_POS >1 PEAKXDs do not use these flight software (FSW) patchable constants as they use the LTAPKD FSW macro used in ACQ-PEAKD comma but re-purposed for use in the cross-dispersion (XD). This program uses the HST standard star WD1657+343. This target was used previously in the COS TA Monitor programs comma 13124 (C20) comma 13526 (C21) comma 13972 (C22) comma 14440 (C23) comma 14857 (C24) comma 15386 (C25) comma 15537 (C26) and 15775 (C27). We re-use this target here as it is safe with PSA-MIRRORA and visible almost year-round.