Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1291c Report Date: 09-May-96:16:26 Version: ********** Check-in Date: ********** 1.Proposal Title: COMET HALLEY HYDROGEN CORONA ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/OS Sub Category COMETS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone John J. Caldwell YORK UNIVERSITY CANADA (416) 736-2100 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract The red leak will be a major problem for most attempts at planetary imaging with the WF/PC using the Lyman alpha filter. However, for comets, the OAO-2 discovered a very extended corona consisting of atomic H. Thedetection was possible because of the strong Lyman alpha signal due to resonant scattering of the Solar feature at that wavelength. For comets, the red leak would grossly distort the image of the near- nuclear region, but will not effect the extended atmosphere very much. As comet Halley recedes in 1986-87, the HST should be uniquely able to monitor the final stages of its activity. ------------------------------------------------------------------------------------ 8. Scientific Key Words: COMET HALLEY, HYDROGEN CORONA, LYMAN ALPHA ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 0.50 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1291c PI: John J. Caldwell Proposal Title: COMET HALLEY HYDROGEN CORONA ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ John J. Caldwell YORK UNIVERSITY CANADA ------------------------------------------------------------------------------------ 3. Description of proposed observations. This proposal consists of a single exposure, which should be made as soon after ST launch as possible. It requires only a rudimentary tracking capability. It is not sensitive to red leak problems. The nucleus will certainly be over-exposed because of the red leak there, but that should not hurt the coronal observations. There is no red leak in the corona because the Lyman alpha emission is the strongest feature inthe spectrum of the corona. comment continuation fronm CP section 11 Sepcial Requirements: "Observe as soon as possible, unless GTO extends to 2060" comment continutation from EL Page 4, Line 1: Observation should be made as soon as possible. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The ST is needed because it is the most sensitive instrument available which can image at 1200 A. Ground-based observations are not relevant. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The only special scheduling requirement is that it be done as soon as possible, preferably immediately after the WF/PC is turned on. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. DARK TIME IS REQUIRED BECAUSE THE SKY IS EXTREMELY BRIGHT IN LYMAN ALPHA DURING ORBITAL DAYTIME. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The image will be examined for excess hydrogen emission near the nucleus. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. A parallel ST observation of the sky near the comet is being planned. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). We have access to a VAX computer in the Engineering Department of SUNY to supplement the resources of the ST ScI. ------------------------------------------------------------------------------------ 13. A WFC Lyman alpha exposure of Comet Halley will be obtained as soon as possible after HST launch to monitor atomic H coronal acitivity as the comet recedes. The red leak should not be a problem for this observation, because only the nucleus will be affected. ------------------------------------------------------------------------------------ 11. Address Information Page 3 Name: JOHN J. CALDWELL Category: PI Institution: YORK UNIVERSITY Address: PHYSICS DEPT. 4700 KEELE ST. City: NORTH YORK State: ON Zip Code: M3J 1P3 Country: CANADA Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 1291c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: COMET-HALLEY ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: COMET HALLEY ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = HALLEY | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | | | TRK = 0.1 | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1291c [ 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 COMET- WFC IMAGE ALL F122M PURGE=YES 1 30M 1 DARK TIME HALLEY POS TARG +4, +4 CYCLE 2 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1291c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PURGE=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/OS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 0.50 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category COMETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements DARK TIME; POS TARG +4, +4; CYCLE 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F122M ------------------------------------------------------------------------------------------------------------------------------------ Target Names COMET-HALLEY ------------------------------------------------------------------------------------------------------------------------------------