Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 3367c Report Date: 09-May-96:18:32 Version: ********** Check-in Date: ********** 1.Proposal Title: WFPC ASTROMERTRIC CALIBRATION PLATE DISTORTION, POINTING ASSISTANCE CALIBRATION. ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID CAL/WFC Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. Roberto Gilmozzi STSCI USA (301)338-4760 I. SCIENTIST - TEL ------------------------------------------------------------------------------------ 7. Abstract The purpose of this calibration test is to determine the plate distortions in the WFPC for assisted target acquisition for the small-aperture science instruments and for calibrating WFPC astrometric performance. The target field is observed at several overlapping positions so that many stellar separations of various sizes and position angles can be measured in different regions of each CCD. The observations provide their own PSF data. These observations are crucial for the GO observations of Pluto and Charon, and should be scheduled close to them. ------------------------------------------------------------------------------------ 8. Scientific Key Words: ASTROMETRIC CALIBRATION OF WF/PC ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 0 par: 0 10. Num targs pri: 0 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 3367c PI: Dr. Roberto Gilmozzi Proposal Title: WFPC ASTROMERTRIC CALIBRATION PLATE DISTORTION, POINTING ASSISTANCE CALIBRATION. ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Roberto Gilmozzi STSCI USA Shawn Ewald STSCI USA Richard White STSCI USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. This calibration is crucial for the supporting of WFPC assisted target acquisitions. It has been shown, in fact, that the WFPC displays a substantial geometrical distortion (up to 0.2" over 20") which would impair any astrometry performed with it, and in particular any measurements intended for subsequent "blind offsets" with other, small aperture, instruments. Gilmozzi and White (1991) have however shown that it is possible to remove the distortion (at least in the area analized by them, about half of one chip) down to a level of 0.01". This proposal extends the calibration to the whole field of view of both WFC and PC, although the first step will be to calibrate only the "default" chips (W2 and P6). To do so we plan to observe a moderately crowded globular cluster in the LMC (NGC1850) for which we already have a set of observations in August and September 1990 (used for the quoted analysis). The telescope will be moved at 5 different position within the cluster so as to have the same group of stars in each quadrant and in the center of the chip. Comparing the relative positions of the stars in each sector will yield the relative distortion between sectors, which will be then tied together in the central, overlapping area. The outcome of this proposal will be a two-dimensional polinomial which will be used to correct the x,y coordinates of each chip. The use of the same target as in the study by Gilmozzi and White will allow us to check for long term stability of the distortion. The observations will be performed in the F555W filter (probably the standard for this sort of astrometric measurements). We will however check for wavelength dependence of the distortion by taking a single image in F439W (an image in the F785LP is already in hand). ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Instrument calibration. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. This is a calibration activity for which the prerequsites are that the WF/PC is UV-flooded, if we are using a flood, and the final telescope focus and collimation be adopted. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Avoid the SAA for all exposures. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. These data will be analyzed at STScI and the results will be part of the ScI calibration data base and will be included in WF/PC Instrument Science or Target Acquisition reports. ------------------------------------------------------------------------------------ 11. Address Information Page 3 Name: ROBERTO GILMOZZI Category: PI Institution: STSCI Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ Name: SHAWN EWALD Category: CON Institution: STSCI Address: 3700 SAN MARTIN DR. City: BALTIMORE State: MD Zip Code: 21218 Country: USA Telephone: 301-338-4927 Telex (or e-mail): ------------------------------------------------------------------------------------ Name: RICHARD WHITE Category: CON Institution: STSCI Address: 3700 SAN MARTIN DR. City: BALTIMORE State: MD Zip Code: 21218 Country: USA Telephone: 301-338-4797 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 3367c [ 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 NGC1850 YOUNG CLUSTER RA = 05H 08M 59S +/-1.0S, 1950 DEC = -68D 49' 24" +/- 5.0" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3367c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1.1 NGC1850 WFC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 SEQ 1.1-1.6 NO GAP PRE-FLASH=YES CYCLE 1 / 1.1-2.6 POS TARG -10,10 Comments: AVOID SAA FOR ALL EXPOSURES. USE SAME GUIDE STARS FOR 1.1- 1.6, IF POSSIBLE. SCHEDULE LINES 1-1.6 DURING SAME WEEK AS PLUTO/CHARON OBSERVATION FROM GO PROP 2215. ------------------------------------------------------------------------------------------------------------------------------------ 1.2 NGC1850 WFC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 POS TARG +10,-10 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 1.3 NGC1850 WFC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 POS TARG -30,-10 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 1.4 NGC1850 WFC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 POS TARG -30,+30 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 1.5 NGC1850 WFC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 POS TARG +10,+30 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 1.6 NGC1850 WFC IMAGE ALL F439W CR-SPLIT=0.5 1 2200S 1 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 2.1 NGC1850 PC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 SEQ 2.1-2.6 NO GAP PRE-FLASH=YES POS TARG -10,10 Comments: AVOID SAA FOR ALL EXPOSURES. USE SAME GUIDE STARS FOR 2.1- 2.6, IF POSSIBLE ------------------------------------------------------------------------------------------------------------------------------------ 2.2 NGC1850 PC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 POS TARG -26,-6 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 2.3 NGC1850 PC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 POS TARG -26,26 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 2.4 NGC1850 PC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 POS TARG 6,26 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 2.5 NGC1850 PC IMAGE ALL F555W CR-SPLIT=NO 1 300S 1 POS TARG 6,-6 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ 2.6 NGC1850 PC IMAGE ALL F439W CR-SPLIT=0.5 1 2200S 1 PRE-FLASH=YES ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 3367c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC PC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO PRE-FLASH=YES CR-SPLIT=0.5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for CAL/WFC ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SEQ 1.1-1.6 NO GAP; CYCLE 1 / 1.1-2.6; POS TARG -10,10 POS TARG +10,-10 POS TARG -30,-10 POS TARG -30,+30 POS TARG +10,+30 SEQ 2.1-2.6 NO GAP; POS TARG -26,-6 POS TARG -26,26 POS TARG 6,26 POS TARG 6,-6 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F439W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1850 ------------------------------------------------------------------------------------------------------------------------------------