6841( 8) - 02/09/96 10:04 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6841 Version: 8 Check-in Date: 09-Feb-1996 09:55:11 1.Proposal Title: The Nucleus of Comet H-M-P ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Solar System GO/DD 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Michael F. A'Hearn University of Maryland CoI: Harold A. Weaver Applied Research Corporation N CoI: Philippe Lamy Laboratoire d'Astronomie Spatiale N ------------------------------------------------------------------------------------ 6. Abstract The WFPC2 will be used for photometry and colorimetry of the nucleus of comet 45P/Honda-Mrkos-Pajdusakova during its remarkably close approach to Earth in early February 1996. ------------------------------------------------------------------------------------ 6841( 8) - 02/09/96 10:04 - [ 2] Observations Description ------------------------ These observations should be scheduled during the first week of February 1996 in order to catch the comet near its minimum geocentric distance. Ideally they would be coincident with a ground-based observing run which we have requested on Feb 3-5 (UT) although shifting one or two days beyond either end is possible without too much degradation in the interpretation. Since the comet will have an apparent geocentric motion of about 0.16 arcsec/sec, GS selection might be problematic. We emphasize that the primary scientific objective of this program requires the full spatial resolution capabilities of HST. Thus, we cannot tolerate any target drift that results in image smear of more than the rms jitter associated with FINE-LOCK tracking (i.e., more than 7 mas rms). However, if the gyro drift is roughly at its nominal value (of 1 mas/sec), then we estimate that we can tolerate single GS tracking (which would permit rotation about the selected GS) for exposure times of 20 sec or less. So we would consider using single GS tracking if a pair of GSs cannot be found to support these observations. Our program uses two orbits with the second being a repeat of the first in order to search for temporal variability and/or possible color changes with rotational phase. We hope to take images through the R (F675W), U (F336W), B (F439W), I (F814W), V (F555W), and R (F675W again) filters during each orbit. The specific sequence of observations is: Orbit no. 1: 2 F675W images with exp times of 3 sec and 10 sec 2 F336W images with exp times of 140 sec and 400 sec (exp times can be adjusted) 2 F439W images with exp times of 40 sec and 120 sec 2 F814W images with exp times of 3 sec and 10 sec 2 F555W images with exp times of 4 sec and 12 sec 2 F675W images with exp times of 3 sec and 10 sec Orbit no. 2 is simply a repeat of orbit no. 1. Since it is unlikely that the same pair of GSs will support both orbits, we have structured our program as requiring two separate visits. However, you can restructure the program if that would provide more efficient scheduling. In any case, we want to use consecutive orbits. We estimate that the above activities will require about 53 mins, which means that the visibility window is tightly packed. If all 12 exposures cannot fit in one orbit, then you should adjust the exp times for the F336W filter to make a fit. The general approach in CR splitting is to increase our dynamic range (because the magnitude of the nucleus is so uncertain by splitting the exposure in roughly a 3:1 ratio but this can be changed in order to increase the total observing time available, particularly in the F336W observations. As these observations are TIME-CRITICAL, we request that you contact the PI immediately to resolve any issues that arise during scheduling. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6841( 8) - 02/09/96 10:04 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6841( 8) - 02/09/96 10:04 - [ 4] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: COMET-45P ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: COMET 45P-HONDA-MRKOS-PAJDUSAKOVA ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET,Q=0.5320503,E=0.8242449,I=4.2 | 4877,O=89.15246,W=326.05550,T=25-Dec- | 1995:23:45:20.0,EQUINOX=J2000,EPOCH=29- | Dec-1995 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | B-V = 0.75+/-0.2 | Magnitude of nucleus is very V = 13.7+/-2.5 | uncertain. Magnitude of coma in any | pixel is faint compared to nucleus. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: COMET-45P-2 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: COMET 45P-HONDA-MRKOS-PAJDUSAKOVA ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET,Q=.05320503,E=.8242432,I=4.24 | 869,O=89.15214,W=326.05763,T=25-Dec- | 1995:23:38:41.0,EQUINOX=J2000,EPOCH=29- | Dec-1995 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 13.7+/-2.5 | Magnitude of nucleus is very B-V = .75+/-.2 | uncertain. Magnitude of coma in any | pixel is faint compared to nucleus. | ------------------------------------------------------------------------------------------------------------------------------------ 6841( 8) - 02/09/96 10:04 - [ 5] Visit: 01 Visit Requirements: BETWEEN 03-Feb-1996:09:36:00.0 AND 07-Feb-1996:09:36:00.0 On Hold Comments: Additional Comments: All exps should be completed within one orbit. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 COMET-45P WFPC2 IMAGE PC1 F675W CR- 1 14.0S SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 12 COMET-45P WFPC2 IMAGE PC1 F336W CR- 1 600.0S MIN DUR 30% EXPAND SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 13 COMET-45P WFPC2 IMAGE PC1 F439W CR- 1 160.0S SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 14 COMET-45P WFPC2 IMAGE PC1 F814W CR- 1 14.0S SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 15 COMET-45P WFPC2 IMAGE PC1 F555W CR- 1 16.0S SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 16 COMET-45P WFPC2 IMAGE PC1 F675W CR- 1 14.0S END ORBIT SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 6841( 8) - 02/09/96 10:04 - [ 6] Visit: 02 Visit Requirements: BETWEEN 03-Feb-1996:09:36:00.0 AND 07-Feb-1996:09:36:00.0 On Hold Comments: Additional Comments: All exps should be completed within one orbit. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 COMET-45P-2 WFPC2 IMAGE PC1 F675W CR- 1 14.0S REQ EPHEM CORR HMPFIX SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 22 COMET-45P-2 WFPC2 IMAGE PC1 F336W CR- 1 600.0S REQ EPHEM CORR HMPFIX MIN DUR 30% EXPAND SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 23 COMET-45P-2 WFPC2 IMAGE PC1 F439W CR- 1 160.0S REQ EPHEM CORR HMPFIX SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 24 COMET-45P-2 WFPC2 IMAGE PC1 F814W CR- 1 14.0S REQ EPHEM CORR HMPFIX SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 25 COMET-45P-2 WFPC2 IMAGE PC1 F555W CR- 1 16.0S REQ EPHEM CORR HMPFIX SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 26 COMET-45P-2 WFPC2 IMAGE PC1 F675W CR- 1 14.0S REQ EPHEM CORR HMPFIX END ORBIT SPLIT=0.25,ATD- GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ 6841( 8) - 02/09/96 10:04 - [ 7] Summary Form for Proposal 6841 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.25 ATD-GAIN=7 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/DD ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Solar System ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 03-Feb-1996 09 36 00.0 AND 07-Feb-1996 09 36 00.0 MIN DUR 30% EXPAND END ORBIT REQ EPHEM CORR HMPFIX REQ EPHEM CORR HMPFIX MIN DUR 30% EXPAND REQ EPHEM CORR HMPFIX END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F675W F336W F439W F814W F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names COMET-45P COMET-45P-2 ------------------------------------------------------------------------------------------------------------------------------------