7594( 2) - 03/26/97 14:19 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7594 Version: 2 Check-in Date: 26-Mar-1997 14:16:37 1.Proposal Title: Observations of comet Spacewatch (1996 BA6) ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle SOLAR SYSTEM GO/DD 7 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: ALEX STORRS SPACE TELESCOPE SCIENCE INSTITUTE CoI: Larry Petro STScI N CoI: Dave Jewitt Univ. of Hawaii N ------------------------------------------------------------------------------------ 6. Abstract We propose one orbit of imaging observations of comet 1996 BA6 (Spacewatch). This recently discovered comet is on a very odd orbit, highly inclined and eccentric, with a perihelion in the asteroid belt. It is quite bright (V=19.5) in the outer solar system (R=9 AU) indicating a fairly large nucleus (16-40 km radius). WFPC2 V and R images with dithering could resolve the nucleus upon reconstruction, allowing a determination of its albedo. If resolved, this would be the second comet (after P/Halley) to have its albedo unambiguously determined. ------------------------------------------------------------------------------------ Observations Description ------------------------ One orbit of WFPC2 observations is planned, to execute as soon as possible. The F555W and F702W filters will be used to obtain SNR=100 or more images. Four images in each filter should fill an orbit. A box type dithering strategy is planned, to maximize the spatial information. These observations should be made as soon as possible, to minimize the time a coma has to develop and obscure the nucleus. Real Time Justification ----------------------- none Calibration Justification ------------------------- nothing special required Additional Comments ------------------- ------------------------------------------------------------------------------------ 7594( 2) - 03/26/97 14:19 - [ 2] Data Distribution Media: ELECTRONIC Blocking Factor: 10 Ship To: STSCI Ship Via: Email: storrs@stsci.edu ------------------------------------------------------------------------------------ 7594( 2) - 03/26/97 14:19 - [ 3] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: SPACEWATCH ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: COMET COMET 1996 BA6 ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET,Q=3.4397678,E=1.0027529,I=72. | TYPE=POS_ANGLE,RAD=10,ANG=180,REF=SUN,EP 97463,O=317.69229,W=285.81463,T = 27-Nov | OCH=01-Jan-1997 -1999:05:40:23.0,EQUINOX=J2000,EPOCH=01- | Jun-1997 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 19.5+/-1 | Elements from IAU/CfA computer (Mar. TYPE=G5V | 18, 1997). May need to be updated. | Offset 10" sunward to move target | nearer V1 axis. | Ephemeris Uncertainty: 130000 KM | ------------------------------------------------------------------------------------------------------------------------------------ 7594( 2) - 03/26/97 14:19 - [ 4] Visit: 01 Visit Requirements: BETWEEN 21-Apr-1997 AND 01-Jun-1997 On Hold Comments: Additional Comments: Single guidestar control is fine for this visit. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 SPACEWATCH WFPC2 IMAGE PC1-FIX F555W 1 100 S REQ EPHEM CORR BA6 ------------------------------------------------------------------------------------------------------------------------------------ 20 SPACEWATCH WFPC2 IMAGE PC1-FIX F702W 1 100 S REQ EPHEM CORR BA6 ------------------------------------------------------------------------------------------------------------------------------------ 30 SPACEWATCH WFPC2 IMAGE PC1-FIX F555W 1 100 S POS TARG 0.5,0.25 REQ EPHEM CORR BA6 ------------------------------------------------------------------------------------------------------------------------------------ 40 SPACEWATCH WFPC2 IMAGE PC1-FIX F702W 1 100 S SAME POS AS 30 ------------------------------------------------------------------------------------------------------------------------------------ 50 SPACEWATCH WFPC2 IMAGE PC1-FIX F555W 1 100 S POS TARG 0.75,0.75 REQ EPHEM CORR BA6 ------------------------------------------------------------------------------------------------------------------------------------ 60 SPACEWATCH WFPC2 IMAGE PC1-FIX F702W 1 100 S SAME POS AS 50 ------------------------------------------------------------------------------------------------------------------------------------ 70 SPACEWATCH WFPC2 IMAGE PC1-FIX F555W 1 100 S POS TARG 0.25,0.5 REQ EPHEM CORR BA6 ------------------------------------------------------------------------------------------------------------------------------------ 80 SPACEWATCH WFPC2 IMAGE PC1-FIX F702W 1 100 S SAME POS AS 70 ------------------------------------------------------------------------------------------------------------------------------------ 7594( 2) - 03/26/97 14:19 - [ 5] Summary Form for Proposal 7594 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/DD ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 21-Apr-1997 AND 01-Jun-1997 REQ EPHEM CORR BA6 POS TARG 0.5,0.25 REQ EPHEM CORR BA6 SAME POS AS 30 POS TARG 0.75,0.75 REQ EPHEM CORR BA6 SAME POS AS 50 POS TARG 0.25,0.5 REQ EPHEM CORR BA6 SAME POS AS 70 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F702W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SPACEWATCH ------------------------------------------------------------------------------------------------------------------------------------