Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 3267c Report Date: 09-May-96:18:18 Version: ********** Check-in Date: ********** 1.Proposal Title: FIND GHRS MIRROR A1 COORDINATES ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SV/HRS Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dennis Ebbets BALL AEROSPACE USA 303 939 5964 ------------------------------------------------------------------------------------ 7. Abstract This is a new SV test whose purpose is to help calibrate the onboard data base coordinates used by target acquisition mirror A1 to center a star in the 2.0 arc sec LSA during an onboard target acquisition. This is needed to ensure proper centering in the LSA before slewing to the SSA. We have not yet been successful in getting stars well centered in the SSA with mirror A1. Many SV, GTO GO programs will use bright stars, for which A1 is the essential choice of acquisition mirror. revised and shortened July 23, 1991 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.58 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 3267c PI: Dennis Ebbets Proposal Title: FIND GHRS MIRROR A1 COORDINATES ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Dennis Ebbets BALL AEROSPACE USA Harry Garner BALL AEROSPACE USA ------------------------------------------------------------------------------------ 2. Scientific Justification. Mirror A1 is used for target acquisition of bright blue stars. For the most part all stars brighter than about V=6 use A1. This includes many of the most popular targets for interstellar medium studies, and several SV calibration stars. The flight software peakup algorithm moves the telescope until the measured position of a star coincides with the onboard data base value of its coordinates in detector deflection units. The software does not directly sense the geometrical center of the aperture. The software does not attempt to maximize the flux through the aperture. Any error in the onboard coordinates leads directly to an error in target centering. The attenuation with A1 is so great that we cannot detect the onboard spectral lamps, and therefore cannot perform a deflection calibration. Since some kind of calibration is necessary, we do the defcal with mirror N1, then the acq with A1. The offset between the N1 defcal and the A1 coordiantes has not been successfully established yet. Assuming that a stable offset even exists, this test is designed to measure it and make A1 useful for SSA applications. Without a good calibration, stars acquired with A1 will be misplaced at the SSA, and the desired S/N ratio will not be achieved. ------------------------------------------------------------------------------------ 3. Description of proposed observations. Part 1 - lines 10 - 80 onboard acq with mirror N1, peakup in LSA, map LSA take a short spectrum with G140L with star in LSA slew to SSA, map SSA, take same spectrum in SSA return to LSA, peakup and map again this leaves the star well centered in the LSA We think that N1 is very well calibrated, and will place the star accurately in both apertures. The spectra will show the true throughput ratio at 1300A when well centered. Part 2 - lines 110 - 160 initial image of LSA with A1 showing where N1 put the star peakup with A1, image LSA, short spectrum with G140L this will show how much A1 moved the star relative to N1's correct position. slew to the SSA, image, and repeat the spectrum - this should show a decreased ratio of SSA/LSA throughput due to miscentering return to LSA. These will measure the offset between N1 and A1 Part 3 lines 200 - 250 cycle back and forth between N1 and A1, doing only peakups in the LSA. each peakup will be preceeded by an N1 defcal. Since these are short exposures, they should be close to each other in time, so thermal and magnetic drift differences should be small. Analyze the offsets between A1 and N1 to derive a new estimate of the best onboard db position for A1 lines 900, 910 use the sequence twice, about 30 days apart the second execution should be after the A1 position has updated in the data base. Hopefully the offsets between A1 and N1 will be much smaller this time. The SSA/LSA flux ratio observed with the spectra should be independent of which mirror is used for centering. time estimates: each visit = 1.79 hrs (resource) * 1.5 = 2.7 hrs SU duration ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The precise position of the A1 image was not well determined during the ground based calibration programs. We have not been successful in inferring it from other data taken for other SV and SAO observations. We feel it is necessary to make this dedicated measurement to get a good calibration. Page 3 ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The centroids of all the images will be measured to fix the X,Y position of the stellar image after each peakup. The initial pointing offset detected by the flight software is in the trailing UDL of each peakup data set. These numbers will be analyzed, averaged probably, to determine a mean error in the A1 position after an N1 defcal The revised A1 position will be placed in PDB PTLD table ZFDEFXNC for A1_LSA, A1_SSA, A1_SC1, A1_SC2 ------------------------------------------------------------------------------------ 11. Address Information Name: DENNIS EBBETS Category: PI Institution: BALL AEROSPACE Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ Name: HARRY GARNER Category: COI Institution: BALL AEROSPACE SYSTEMS GROUP Address: PO BOX 1062 AR 1 City: BOULDER State: CO Zip Code: 80306 Country: USA Telephone: 303 939 4816 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 3267c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 BD+75D325 UV STANDARD RA = 8H 10M 49.31S +/- 0.5S, 2000 1 V=9.54 DEC= +74D 57' 57.5" +/- 0.5" 2 B-V=-0.36 3 F-CONT(1240)=8.0E-11 Comments: PLATE-ID=00LQ Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B 1983.80 -0.0005 +/- 0.0004 0.0120 +/- 0.0100 0.0000 +/- 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3267c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 DEF BD+75D325 HRS ACQ 2.0 MIRROR-N1 SEARCH-SIZE=5 1 5S 50 1 1 ONBOARD ACQ FOR 20 VISIT1 FAINT=4000 -250 CYCLE 0 / 10-250 ------------------------------------------------------------------------------------------------------------------------------------ 20 DEF BD+75D325 HRS ACQ/ 2.0 MIRROR-N1 1 9.2S 50 1 1 VISIT1 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 30 DEF BD+75D325 HRS IMAGE 2.0 MIRROR-N1 1 96.8S 25 1 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 40 DEF BD+75D325 HRS ACCUM 2.0 G140L 1300 STEP-PATT=4 1 57.6S 50 3 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 50 DEF BD+75D325 HRS IMAGE 0.25 MIRROR-N1 DELTA-X=1 1 96.8S 25 1 1 VISIT1 DELTA-Y=1 PRECISION=HIGH ------------------------------------------------------------------------------------------------------------------------------------ 60 DEF BD+75D325 HRS ACCUM 0.25 G140L 1300 STEP-PATT=4 1 288.0S 50 3 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 70 DEF BD+75D325 HRS ACQ/ 2.0 MIRROR-N1 1 9.2S 50 1 1 VISIT1 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 80 DEF BD+75D325 HRS IMAGE 2.0 MIRROR-N1 1 96.8S 25 1 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 100 DEF BD+75D325 HRS IMAGE 2.0 MIRROR-A1 1 484S 25 1 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 120 DEF BD+75D325 HRS ACQ/ 2.0 MIRROR-A1 1 460S 20 1 1 VISIT1 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 130 DEF BD+75D325 HRS IMAGE 2.0 MIRROR-A1 1 484S 25 1 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 140 DEF BD+75D325 HRS ACCUM 2.0 G140L 1300 STEP-PATT=4 1 57.6S 50 3 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 150 DEF BD+75D325 HRS IMAGE 0.25 MIRROR-A1 DELTA-X=1 1 484S 25 1 1 VISIT1 DELTA-Y=1 PRECISION=HIGH ------------------------------------------------------------------------------------------------------------------------------------ 160 DEF BD+75D325 HRS ACCUM 0.25 G140L 1300 STEP-PATT=4 1 288.0S 50 3 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 200 DEF BD+75D325 HRS ACQ/ 2.0 MIRROR-A1 1 230S 50 1 1 VISIT1 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 210 DEF BD+75D325 HRS ACQ/ 2.0 MIRROR-N1 1 9.2S 50 1 1 VISIT1 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3267c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 220 DEF BD+75D325 HRS ACQ/ 2.0 MIRROR-A1 1 230S 50 1 1 VISIT1 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 230 DEF BD+75D325 HRS IMAGE 2.0 MIRROR-N1 1 96.8S 25 1 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 240 DEF BD+75D325 HRS ACQ/ 2.0 MIRROR-N1 1 9.2S 50 1 1 VISIT1 PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ 250 DEF BD+75D325 HRS IMAGE 2.0 MIRROR-N1 1 96.8S 25 1 1 VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 900 USE VISIT1 ------------------------------------------------------------------------------------------------------------------------------------ 910 USE AFTER 900 BY 30D + VISIT1 /- 10D ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 3267c [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=5 FAINT=4000 STEP-PATT=4 DELTA-X=1 DELTA-Y=1 PRECISION=HIGH ------------------------------------------------------------------------------------------------------------------------------------ Proposal for SV/HRS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.58 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 20-250; CYCLE 0 / 10-250; AFTER 900 BY 30D +/- 10D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 G140L MIRROR-A1 ------------------------------------------------------------------------------------------------------------------------------------ Target Names BD+75D325 ------------------------------------------------------------------------------------------------------------------------------------