6130( 0) - 07/18/95 20:13 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6130 Version: ********** Check-in Date: ********** 1.Proposal Title: FOC Objective Prism Observations of SN 1987A ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Peter Jakobsen Astrophysics Division, ESA/ESTEC CoI: P. Greenfield Space Telescope Science Institute N CoI: R. Jedrzejewski Space Telescope Science Institute N CoI: A. Picard Astrophysics Division, ESA/ESTEC N ------------------------------------------------------------------------------------ 6. Abstract We intend to observe SN 1987A and its surroundings with the FOC using the near-UV objective prism. The main purpose of the observations is to carry out a more detailed study of the wavelength dependence of the apparent angular size and shape of the resolved supernova envelope, and thereby gain further information on the emission and absorption processes at work in the ejecta. The data will also be useful for determining the emission processes responsible for the UV flux recently detected from the SN 1987A circumstellar ring. ------------------------------------------------------------------------------------ 6130( 0) - 07/18/95 20:13 - [ 2] Observations Description ------------------------ Our considerable experience with FOC prism observations has shown that the particle and sky background experienced by the FOC varies somewhat with HST orbital position and orientation. Rather than attempt to introduce complex and overly restrictive constraints on the scheduling system, we have instead developed a simple, but effective, observing strategy that involves limiting individual FOC prism exposures of faint targets roughly ~20 minute duration and co -adding the individually reduced exposures in an optimal manner. This technique also has the important benefit of allowing the individual sub-spectra to be shifted slightly on the FOC detector through offset pointing (by a few tenths of an arcsecond) in order to reduce reseau mark and residual flat-field effects in the resulting combined spectrum. Assuming a visibility of 59 minutes for SN 1987A, it follows that two such ~25 minute sub-exposures are achievable per orbit and that a total of ~6 orbits are required to reach the desired total exposure time of ~5 hours. All exposures are blind ``point and shoot'' (Mode III) and no special calibration exposures are required beyond routine Cycle 5 calibrations. Real Time Justification ----------------------- The observations should be scheduled avoiding certain values of the HST Roll angle so as to avoid overlap of the dispersed images of SN 1987A, the two companion stars 2 and 3, and the fainter star superimposed on the ring. This is accomplished for roll angles equivalent to ORIENTATION=30 +\- 15 degrees (or 180 degrees from this roll). We also note that since the images of the two bright companion stars posed no risk to the FOC in terms of excessive countrate during the F275W exposures of Jakobsen et al. (1994), this will also be the case for the observations proposed here, since there is less projected flux per pixel in the near-UV prism than in the F275W filter. (The same does not, however, hold for the visible part of the far-UV prism (PRISM1) -- which is not used in this program) Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6130( 0) - 07/18/95 20:13 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN1987A EXT-MEDIUM,SNR RA = 05H 35M 28.1S +/- 0.1S, DEC 2000 F(2750)=8 +/- 4 E-17 = -69D 16' 13.0" +/- 1" Comments: Extrapolated Day 3000 Flux 6130( 0) - 07/18/95 20:13 - [ 4] Visit: 01 Visit Requirements: ORIENT 195D TO 225D On Hold Comments: Additional Comments: ORIENT 15D TO 45D also OK Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1100S POS TARG 0, -1.4 4 ------------------------------------------------------------------------------------------------------------------------------------ 2 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1100S POS TARG 0, -1.6 4 ------------------------------------------------------------------------------------------------------------------------------------ 3 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG 0, -1.8 4 ------------------------------------------------------------------------------------------------------------------------------------ 4 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG 0.2, -1.4 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG 0.2, -1.6 4 ------------------------------------------------------------------------------------------------------------------------------------ 6 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG 0.2, -1.8 4 ------------------------------------------------------------------------------------------------------------------------------------ 7 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG 0.4, -1.4 4 ------------------------------------------------------------------------------------------------------------------------------------ 8 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG 0.4, -1.6 4 ------------------------------------------------------------------------------------------------------------------------------------ 9 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG 0.4, -1.8 4 ------------------------------------------------------------------------------------------------------------------------------------ 10 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG -0.2, -1.4 4 ------------------------------------------------------------------------------------------------------------------------------------ 11 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG -0.2, -1.6 4 ------------------------------------------------------------------------------------------------------------------------------------ 12 SN1987A FOC/96 IMAGE 512x102 PRISM2 2800 PIXEL=25x25 1 1400S POS TARG -0.2, -1.8 4 ------------------------------------------------------------------------------------------------------------------------------------ 6130( 0) - 07/18/95 20:13 - [ 5] Summary Form for Proposal 6130 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PIXEL=25x25 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 195D TO 225D POS TARG 0, -1.4 POS TARG 0, -1.6 POS TARG 0, -1.8 POS TARG 0.2, -1.4 POS TARG 0.2, -1.6 POS TARG 0.2, -1.8 POS TARG 0.4, -1.4 POS TARG 0.4, -1.6 POS TARG 0.4, -1.8 POS TARG -0.2, -1.4 POS TARG -0.2, -1.6 POS TARG -0.2, -1.8 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements PRISM2 ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN1987A ------------------------------------------------------------------------------------------------------------------------------------