7582( 21) - 08/14/97 09:44 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7582 Version: 21 Check-in Date: 14-Aug-1997 09:43:49 1.Proposal Title: Spatial Distribution of Io's Extended UV Emissions ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Solar System GTO/STIS 7 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: WARREN MOOS THE JOHNS HOPKINS UNIVERSITY CoI: Fred Roesler University of Wisconsin N CoI: Paul Feldman The Johns Hopkins University N CoI: Doyle Hall University of Colorado Y CoI: Melissa McGrath Space Telescope Science Institute N CoI: Ron Oliversen Goddard Space Flight Center N CoI: Frank Scherb University of Wisconsin N CoI: Darrell Strobel The Johns Hopkins University N CoI: Carey Woodward University of Wisconsin N ------------------------------------------------------------------------------------ 6. Abstract Measurements of the spatial distribution of Io's sulfur and oxygen UV emissions will be obtained using STIS spectroscopic modes. This coordinated program uses 6 orbits of STIS GTO time, 3 orbits from PI W. Moos (program 7582) and 3 orbits from PI F. Roesler (prog. 7583). During Visit 1, MAMA FUV spectroscopy will be performed when Io is near western elongation. Visit 2, also near west Io elongation, is devoted to emission line measurements to measure the spatial distribution of the atomic sulfur doublet SI 1900A/1915A and the atomic oxygen doublet OI 1356A/1359A. TIME-TAG mode is used for all observations to monitor the temporal variability of the emissions. ------------------------------------------------------------------------------------ 7582( 21) - 08/14/97 09:44 - [ 2] Observations Description ------------------------ The Moos/Roesler 1997 STIS GTO program to observe Io is a 2-visit, 6-orbit program designed to measure the satellite's FUV and NUV emissions near western elongation. Visit 1 is 3 HST orbits in duration: a DIFFUSE acquisition (no peakup required), followed by several MAMA G140L 52X2 exposures acquired in the TIME-TAG mode. Visit 2 will also observe Io near western elongation using 3 HST orbits: an acquisition followed by MAMA G140M and G230M TIME-TAG spectroscopy in the emission doublets SI 1900A/1915A and OI 1356A/1359A. We request that the observations be scheduled between 10-Aug-1997 and 21-Sep-1997 to facilitate coordinated groundbased observations and minimize terrestrial airglow line emission contamination . However, if scheduling is difficult then this time window could be extended. We also request that the two visits be scheduled as close together in time as possible, (perhaps two consecutive Io western elongations). However, if coupling these observations is difficult, visits 1 and 2 may be scheduled as far apart in time as required by the HST/Io scheduling constraints. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7582( 21) - 08/14/97 09:44 - [ 3] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: IO-WEST-1 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE IO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | STD=IO | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF IO BETWEEN 235 305 | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 5.02 | Io at elongation on Jupiter's west B-V = 1.17 | (dusk) side. The other galilean | satellites must be separated by more | than 10 arcsec from the target (by | default). Here we have made the | orbital longitude (OLG) window | centered at the elongation point +/- | 35 degrees, but this range could be | adjusted slightly to ease | scheduling. | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: IO-WEST-2 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE IO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=JUPITER | STD=IO | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | OLG OF IO BETWEEN 235 305 | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 5.02 | Io at elongation on Jupiter's west B-V = 1.17 | (dusk) side. The other galilean | satellites must be separated by more | than 10 arcsec from the target (by | default). Here we have made the | orbital longitude (OLG) window | centered at the elongation point +/- | 35 degrees, but this range could be | adjusted slightly to ease | scheduling. | 7582( 21) - 08/14/97 09:44 - [ 4] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------------------------ 7582( 21) - 08/14/97 09:44 - [ 5] Visit: 01 Visit Requirements: BETWEEN 22-Sep-1997 AND 15-Oct-1997 On Hold Comments: Additional Comments: Visit 1 must observe a western Io elongation in the period specified near Jupiter opposition (10-Aug-1996). This ensures that the duration of each orbit's SHADOW interval is near its maximum for Cycle 7 Jupiter observations, minimizing terrestrial airglow contamination. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 IO-WEST-1 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 0.1 S ONBOARD ACQ FOR 11 CD P DIFFUSE-CENTER=GEOMETRIC-CENTER, CHECKBOX=25 Comments: Io is a V=5 solar-type source, and its disk projects a diameter between 1.16 and 1.24 arcsec over the requested observation window. A DIFFUSE ACQ with CHECKBOX=25 (1.25 arcsec) with no PEAK-UP is an appropriate choice for these observations that use the 52X2 slit. For acquisitions using the F28X50LP filter and performed near the mid-point of the requested observation period, we calculate that the CCD signal near the center of Io's disk will be approximately 6.2e5 e/s/pixel, and the total signal integrated over the Io-centered checkbox will be about 2.9e8 e/s. For a 0.1 second CCD exposure using the default GAIN of 4, about 1.6e4 DN/px are accumlated at disk-center, roughly a factor of two smaller the CCD saturation limit of 3.6e4 DN/px. During the CCD exposure centered on Io, 7.2e6 DN are accumulated within the checkbox, providing an adequate signal-to-noise ratio for DIFFUSE acquisitions. ------------------------------------------------------------------------------------------------------------------------------------ 11 IO-WEST-1 STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=3000 2 920 S UV-MAM G A Comments: The central wavelength of 1425A provides coverage over the 1150-1730A spectral range. ------------------------------------------------------------------------------------------------------------------------------------ 12 IO-WEST-1 STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=3000 2 1180 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 13 IO-WEST-1 STIS/F TIME-TA 52X2 G140L 1425 BUFFER-TIME=3000 2 1180 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 7582( 21) - 08/14/97 09:44 - [ 6] Visit: 02 Visit Requirements: BETWEEN 22-Sep-1997 AND 01-Oct-1997 On Hold Comments: Additional Comments: Visit 1 must observe a western Io elongation in the period specified near Jupiter opposition (10-Aug-1996). This ensures that the duration of each orbit's SHADOW interval is near its maximum for Cycle 7 Jupiter observations, minimizing airglow contamination. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 20 IO-WEST-2 STIS/C ACQ F28X50L MIRROR ACQTYPE=DIFFUSE, 1 0.1 S ONBOARD ACQ FOR 31 CD P DIFFUSE-CENTER=GEOMETRIC-CENTER, CHECKBOX=25 Comments: Io is a V=5 solar-type source, and its disk projects a diameter between 1.16 and 1.24 arcsec over the requested observation window. A DIFFUSE ACQ with CHECKBOX=25 (1.25 arcsec) with no PEAK-UP is an appropriate choice for these observations that use the 52X2 slit. For acquisitions using the F28X50LP filter and performed near the mid-point of the requested observation period, we calculate that the CCD signal near the center of Io's disk will be approximately 6.2e5 e/s/pixel, and the total signal integrated over the Io-centered checkbox will be about 2.9e8 e/s. For a 0.1 second CCD exposure using the default GAIN of 4, about 1.6e4 DN/px are accumlated at disk-center, roughly a factor of two smaller the CCD saturation limit of 3.6e4 DN/px. During the CCD exposure centered on Io, 7.2e6 DN are accumulated within the checkbox, providing an adequate signal-to-noise ratio for DIFFUSE acquisitions. ------------------------------------------------------------------------------------------------------------------------------------ 31 IO-WEST-2 STIS/N TIME-TA 52X2 G230M 1933 BUFFER-TIME=3000 2 900 S UV-MAM G A Comments: The central wavelength of 1933A provides coverage over the 1888-1978A spectral range. ------------------------------------------------------------------------------------------------------------------------------------ 32 IO-WEST-2 STIS/N TIME-TA 52X2 G230M 1933 BUFFER-TIME=3000 2 1180 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 33 IO-WEST-2 STIS/F TIME-TA 52X2 G140M 1371 BUFFER-TIME=3000 2 1100 S UV-MAM G A Comments: The central wavelength of 1371A provides coverage over the 1344-1397A spectral range. ------------------------------------------------------------------------------------------------------------------------------------ 7582( 21) - 08/14/97 09:44 - [ 7] Summary Form for Proposal 7582 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=DIFFUSE DIFFUSE-CENTER=GEOMETRIC-CENTER CHECKBOX=25 BUFFER-TIME=3000 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GTO/STIS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Solar System ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 22-Sep-1997 AND 15-Oct-1997 ONBOARD ACQ FOR 11 BETWEEN 22-Sep-1997 AND 01-Oct-1997 ONBOARD ACQ FOR 31 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G140L G230M G140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names IO-WEST-1 IO-WEST-2 ------------------------------------------------------------------------------------------------------------------------------------