15457( 5) - 17-May-2018 19:58:39 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15457 Version: 5 Check-in Time: 17-May-2018 19:58:39 STScI Edit Number: 1 Title COS/FUV/G160M/1533 Wavelength Calibration - Dispersion Solution ------------------------------------------------------------------------------------ Type Cycle CAL/COS 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Andrew J. Fox Space Telescope Science Institute - ESA Y CoI: Dr. Bethan Lesley James Space Telescope Science Institute - ESA N CoI: Elaine Mae Snyder Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract This program will observe the emission-line star Epsilon Eridani for use in deriving the dispersion solution for the new G160M/1533 central wavelength at LP4. The G160M dispersion solution is a 1st-order polynomial, so the goal is to derive the dispersion coefficient and zero-point of the wavelength solution. The exposure time and orbit request are driven by the number of counts needed in week FUV emission lines, following program 15365, the wavelength calibration program for the other cenwaves at LP4. We need to achieve at least S/N ~5 (~25 counts) in the peak of the weaker emission lines to allow good cross correlation with the lamp template. Eps Eri is chosen as the target because its spectrum contains many chromospheric emission lines across the FUV bandpass. ------------------------------------------------------------------------------------ Observations Description ------------------------ The primary goal of this program is to obtain spectra of Eps Eri with G160M/1533 to determine the dispersion coefficient and zeropoint of the dispersion solution, which is assumed to be linear. The observations follow those in program 15365 (LP4 wavelegth calibration, PI=Rachel Plesha). The following emission lines will be used as fiducials for our correlations, following program 15365. According to the observations taken in that program, the peak count rates and exposure times to obtain 30 counts (25+1 sigma) in those lines are as follows: G160M FUVA 1681.4 A -> 0.015 counts/s, so 30 counts requires ~2000s G160M FUVB 1485.7 A -> 0.025 counts/s, so 30 counts requires ~1200s Since the FUVA line (1681.4) is fainter, that one drives the exposure time. We verified using the latest version of the ETC (26.1, which includes 1533) that these count levels should be met or exceeded for 1533. Instead of using special commanding, we use the OSM ALIGN command to set the rotation and focus to 1533, as in the 1533 focus sweep program 15452, using the FOCUS and OSM1ROT parameters, which are the relative offsets from 1577 to 1533. This approach works since only 1 FP-POS position (3) is used. Double BOA NUV ACQ/IMAGE target acquisitions will be performed to ensure the best possible target centering for the zero-point measurement, following Program 15365 (which observed Eps Eri, the same target). We checked that using 15457( 5) - 17-May-2018 19:58:39 - [ 2] two ACQ/IMAGES was worthwhile by looking at the size of the TA slews in 15365 Visit 03. In that case, the second ACQ/IMAGE slew was 0.025" in AD and 0.033" in XD, larger than the best precision achievable (0.016" according to Steve Penton), so it is worth keeping the second ACQ/IMAGE, especially given that optimal wavelength precision is needed for this program. The visit is structured as follows 1) BOA+MIRRORB ACQ/IMAGE: 10s (to acquire target, S/N=30) 2) BOA+MIRRORB ACQ/IMAGE: 17s (to refine target centering, S/N=60) 3) G160M/1577: 0.1 s (to configure 1577 , the closest cenwave) 4) OSM ALIGN, FOCUS=-538, OSM1ROT=15 (to configure 1533) 5) G160M/1533: 1952 s (actual exposure, fills the orbit) 6) OSM/ALIGN, FOCUS=0, OSMROT=0 (to return OSM to 1577) The Visit uses SCHED 70, giving a window beginning June 23. We request the data by the end of June, using a BEFORE July 1 timing requirement. ------------------------------------------- SPECIAL REQUESTS: 1. Please turn off calibration for the COS/FUV 1533 exposure (01.005) 2. Please disassociate all exposures. SQL is used to meet the above requests. In case 1 qexposure.control_id is modified. In case 2 qeassociation records are deleted. Please see G. Chapman/M. Reinhart. ------------------------------------------------------------------------------------ 15457( 5) - 17-May-2018 19:58:39 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 EPSILON-ERI EXT-STAR, K V-IV RA=03H32M55.8450S +/- 0.1", J2000 V = V = 3.73 DEC=-09D27'29.73" +/- 0.1" 16.43 Reference Frame: ICRS Extended: NO Comments: This from SIMBAD: eps Eri -- Variable of BY Dra type ICRS coord. (ep=J2000) : 03 32 55.84496 -09 27 29.7312 (Optical) [ 1.84 1.75 90 ] A 2007A&A...474..653V Proper motions mas/yr : -975.17 19.49 [0.21 0.20 0] A 2007A&A...474..653V Radial velocity : V(km/s) 16.43 [0.09] / z(~) 0.000055 [0.000000] / cz 16.43 [0.09] Spectral type: K2Vk: C 2006AJ....132..161G U 5.19 [~] C 2002yCat.2237....0D B 4.61 [~] C 2002yCat.2237....0D V 3.73 [~] C 2002yCat.2237....0D R 3.00 [~] C 2002yCat.2237....0D I 2.54 [~] C 2002yCat.2237....0D J 2.23 [~] C 2002yCat.2237....0D H 1.75 [~] C 2002yCat.2237....0D K 1.67 [~] C 2002yCat.2237....0D Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.06590730479442056 0.019489999999999997 0.31094 ------------------------------------------------------------------------------------------------------------------------------------ 15457( 5) - 17-May-2018 19:58:39 - [ 4] Visit: 01 (Eps Eri G160M/1533) Visit Requirements: SCHED 70% On Hold Comments: Additional Comments: ** Please schedule before the end of June 2018 if possible. I originally used a BEFORE timing constraint to specify this, but removed it at the request of George Chapman after PIT meeting on 5/17/18. We prefer the data in June 2018 to allow us to complete the analysis this summer and deliver the reference files in time for Cycle 26. ** These Eps Eri observations must achieve at least 25 peak counts (~100 total), and preferably >30 peak counts, in the following faint lines for G160M G160M FUVA 1681.4 G160M FUVB 1485.7 Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EPSILON-ERI COS/NUV ACQ/IMA BOA MIRRORB 1 10 S (10 GE S) Comments: ACQ/IMAGE with BOA/MIRRORB, S/N=30 per guideline (exposure time rounded up) ------------------------------------------------------------------------------------------------------------------------------------ 2 EPSILON-ERI COS/NUV ACQ/IMA BOA MIRRORB 1 17 S (17 GE S) Comments: Second ACQ/IMAGE to refine target centering, using S/N=60 for optimal centroiding. ------------------------------------------------------------------------------------------------------------------------------------ 3 EPSILON-ERI COS/FUV TIME-TA PSA G160M 1577 FP-POS=3, BUFFER-TIME=150, 1 0.1 S (0.1 G LIFETIME-POS=LP4, FLASH=NO, S) WAVECAL=NO Comments: This is a dummy exposure used to configure the G160M/1577 cenwave (the closest cenwave to 1533 currently available in APT). Flash = NO to save time. ------------------------------------------------------------------------------------------------------------------------------------ 4 NONE COS ALIGN/O FOCUS=-538, OSM1ROT=15 1 0 S (0 S) SM Comments: FOCUS=-538 is the relative focus offset from 1577 to 1533, as determined from the 1533 focus sweep analysis (program 15452). OSMROT1=15 is the relative rotation offset from 1577 to 1533, exactly as used in the focus sweep program. ------------------------------------------------------------------------------------------------------------------------------------ 15457( 5) - 17-May-2018 19:58:39 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 5 EPSILON-ERI COS/FUV TIME-TA PSA G160M 1577 FP-POS=3, BUFFER-TIME=4288, 1 1952 S G LIFETIME-POS=LP4 (1952 S) Comments: This is the 1533 wavelength calibration exposure. Exposure time calculated using ETC version 26.1 buffer time =2/3 * 6432s = 4288s. The exposure gives S/N>13 per resel in the 1681 emission line, which translates to >>30 counts, the requirement ** Please turn off calibration for this exposure using SQL by modifying qexposure.control_id. ** ------------------------------------------------------------------------------------------------------------------------------------ 6 NONE COS ALIGN/O FOCUS=0, OSM1ROT=0 1 0 S (0 S) SM Comments: This command returns the OSM to the 1577 position. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ EPSILON-ERI 1 COS/NUV ACQ/IMA BOA MIRRORB none none none none 1 N/A GE EPSILON-ERI 2 COS/NUV ACQ/IMA BOA MIRRORB none none none none 1 N/A GE EPSILON-ERI 3 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G NONE 4 COS ALIGN/O none none none none 1 N/A SM EPSILON-ERI 5 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G NONE 6 COS ALIGN/O none none none none 1 N/A SM 15457( 5) - 17-May-2018 19:58:39 - [ 6] Summary Form for Proposal 15457 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures BOA, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS, COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, ALIGN/OSM, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=150, BUFFER-TIME=4288, FLASH=NO, FOCUS=-538, FOCUS=0, FP-POS=3, LIFETIME-POS=LP4, OSM1ROT=0, OSM1ROT=15, WAVECAL=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SCHED 70% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G160M, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names EPSILON-ERI, NONE ------------------------------------------------------------------------------------------------------------------------------------