6545( 8) - 06/10/96 17:22 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6545 Version: 8 Check-in Date: 10-Jun-1996 17:18:10 1.Proposal Title: Simultaneous Multiwavelength Observations of the Dwarf Nova Oscillations of SS Cygni ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle BINARIES AND STAR FOR GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: CHRISTOPHER MAUCHE LAWRENCE LIVERMORE NAT'L LAB. CoI: Carole Haswell Columbia University N CoI: Janet Mattei AAVSO N CoI: Joe Patterson Columbia University N CoI: Edward Robinson University of Texas N CoI: William Welsh Keele University N ------------------------------------------------------------------------------------ 6. Abstract After many years of murky views of the boundary layers of CVs, EUVE recently has provided "high" spectral resolution (Lambda/DeltaLambda ~ 200) EUV spectra of a number of dwarf novae in outburst. EUVE has also measured the dwarf nova oscillations in the boundary layer radiation of SS Cyg, and determined the spectrum of the oscillations for the first time. This boundary layer radiation has important effects on the winds of CVs, on the white dwarf primary, the secondary, and the accretion disk. Reprocessing of the boundary layer radiation is manifest in the He II lines in the optical and UV and in the low-amplitude oscillations in the optical flux of CVs. Multicolor optical photometry strongly implies that the amplitude of these oscillations will be strong in the UV, but no measurements exist to confirm this prediction. Worse yet, no measurements exist in the optical or UV with sufficient spectral resolution to distinguish the lines from the continuum. To study the reprocessing of the boundary layer radiation in the optical and UV, we propose to undertake a multiwavelength campaign using XTE, EUVE, HST, and ground- based optical telescopes to characterize the dwarf nova oscillations of SS Cyg. We will use the HST FOS/BL G160L and GHRS G140L gratings to separately measure the response of the UV lines and continuum to the EUV/soft X-ray oscillations of the boundary layer flux. Due to the high count rates and the required high time resolution, these observations cannot be performed with the STIS. ------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 2] Observations Description ------------------------ Observations of SS Cyg in outburst require target-of- opportunity scheduling and will be triggered by an alert by the AAVSO. The number of visits to the source is set by the length of the outburst, the interval between visits, and the reaction time of HST. The long outbursts of SS Cyg last ~21 days (see Fig. 2) and observations are required every 2-3 days to measure the response of the UV lines and continuum to the changing luminosity, temperature, period, amplitude, coherence, of the EUV/soft X-ray oscillations. Six visits to the source are requested. Assuming HST takes 3 days to react, the 6 visits should be distributed evenly over an interval of 14 days (~2.8 days between visits). If HST takes 5 days to react, the 6 visits should be distributed evenly over an interval of 12 days (~2.4 days between visits). These observations will sample the plateau and decline phases of a long outburst of SS Cyg. If the outburst is instead narrow, the last 2-3 visits will measure the quiescent spectrum. The FOS/BL G160L is to be used for observations during the first orbit of each visit; the GHRS G140L is to be used for observations during the second orbit of each visit. We discuss each of these instruments is turn. NOTICE: To ease the scheduling of these observations, we have reduced the minimum time between visits from 2 days to 1 day. Subsection FOS/BL G160L: To adequately sample the 7.2-11 s oscillation of SS Cyg, RAPID read-out is required. To obtain read times below 2 s with reasonable duty cycles with the low telemetry rate, we require SUB-STEP=1. The recommended minimum READ-TIME for this configuration is 1.86 s, which results in a duty cycle of 80% and integrations of 1.5 s. Shorter READ-TIMEs (with integrations of ~1 s; obtained at the expense of lower duty cycles) will be attempted only after discussion with the FOS team. Note that co -I B. Welsh has extensive experience using the FOS in "ultra-RAPID" mode. We choose the upper 1" square aperture to avoid the "C IV" scratch on the photocathode, and to suppress geocoronal Lyman Alpha, which otherwise may affect the blue wing of N V Lambda 1240. For dispersing elements, we wish to use the G160L grating because of its wide (1140-2508 Angstrom) bandpass and because it allows a simultaneous background measurement and a measurement of the undispersed zero order light (Gaussian bandpass, Lambda_0=3400 Angstrom, FWHM=1900 Angstrom; Eracleous et al. 1994). With this configuration and a typical IUE spectrum of SS Cyg in outburst (SWP 1788; datum appearing at relative JD = 6 days in Fig. 2), the count rate distribution for the G160L grating is shown in Figure 3: it is reasonably flat between 1300 and 2000 Angstrom at a value of ~1000 counts s^-1 diode^-1; below 2000 Angstrom, the distribution rises roughly linearly to ~3400 counts s^-1 diode^-1 at 2500 Angstrom. The total count rate of dispersed light is ~270,000 counts s^-1. The count rate for the zeroth order light for this grating is less certain, but we estimate that it will be ~560,000 counts s^-1 diode^-1. These rates are all significantly below the light limits for the FOS Digicon detectors: 1.5*10^6 pe s^-1 diode^-1 for the dispersed light, and 4*10^6 pe s^-1 diode^-1 for the zero order light (Hartig 1988). The count rates during decline from outburst can be scaled from the UV continuum flux densities shown in Figure 2. NOTICE: We have discussed the issue of shorter READ-TIMES with J. Hayes (02/07/96) and been advised that there should be no problems working at READ-TIME=1.0 s, the value used below. We envision working at low telemetry rates to AVOID filling the tape recorders and limiting our exposures to ~20 min. NOTICE: For the Phase I proposal, we used a "typical" IUE spectrum of SS Cyg to calculate the count rates of the dispersed and zero-order light. The BRIGHTEST IUE spectrum of SS Cyg ever recorded produces count rates which are ~33% higher than the values quoted above. Hence, we remain well below the FOS light limits for the dispersed and zero order light. Subsection GHRS G140L: It is (just) possible to obtain similar read times with the GHRS in ACCUM mode: with STEP-PATT=2, COMB=4, FP-SPLIT=NO, and STEP-TIME=0.2, the exposure time is 1.6 s. Shorter exposures (with integrations of ~1 s; either with STEP-PATT=1 or in RAPID mode) will be attempted only after discussion with the GHRS team. We choose the Large Science Aperture to avoid the factor of ~2 decrease in sensitivity associated with the Small Science Aperture and to allow the switch from the FOS to the GHRS without additional overhead. Furthermore, scattered light is not a problem in the GHRS, and we will not be working near Lyman Alpha. We will perform a WAVCAL at the beginning and end each run with the GHRS. For dispersing elements, we wish to use the G140L grating because of its moderately wide (286 Angstrom) bandpass and (for our needs) excellent (0.57 Angstrom) spectral resolution. We will center the grating at 1515 Angstrom to allow simultaneous measurements of Si IV Lambda 1400, C IV Lambda 1550, and He II Lambda 1640. With the same assumptions as above, the count rate distribution for the G140L grating rises strongly toward short wavelengths (see Fig. 3): it is ~55 counts s^-1 diode^-1 at He II, ~115 counts s^-1 diode^-1 at C IV, and ~310 counts s^-1 diode^-1 at Si IV. The signal-to-noise ratio for the continuum in the neighborhood of these lines is respectively ~9, 13, and 22 for 1.6 s integrations. On the decline from outburst, high signal-to-noise ratios will be maintained by phase folding. NOTICE: Below we use STEP-PATT=1 to obtain 0.8 s time resolution (at the expense of a small degradation in spectral resolution). Subsection Target Acquisition Strategy: We will allocate 2 orbits for careful target acquisition into the upper 1" square aperture (after consultation with the FOS team) on the first and second visits, and employ the "reuse_target_offset" procedure on the third and subsequent visits to cut down on overheads. The sequence during the first and second visits is as follows. 1st orbit: ACQ/PEAK. 2nd orbit: ACQ/PEAK + FOS/BL G160L to pack orbit. 3rd orbit: FOS/BL G160L. 4th orbit: GHRS G140L. NOTICE: We find that target acquisition can be accomplished in 1 orbit, so we have used the 2nd orbit of the 1st and 2nd visits for FOS exposures. If target acquistion turns out to require more than 1 orbit, the 1st FOS exposure of the 1st and 2nd visits can be shortened to pack that orbit. Real Time Justification ----------------------- Target-of-opportunity observations. Probability of occurrence during Cycle 6 is 100%: outbursts of SS Cyg occur every 50+/- 15 days. We wish to observe the first long outburst after the beginning of Cycle 6 on 1996 July 1 to assure that ground -based optical coverage can be obtained. Operationally, we will observe the first outburst after 1996 July 1 following a short outburst. Long outbursts follow short outbursts 65% of the time. These odds of catching a long outburst can be increased to 80-90% if the previous outburst behavior is examined. Observations must be completed before 1996 October 28 so that EUVE can observe the source. The typical reaction time of HST of 2-5 days is sufficient to obtained the requested coverage, although 2-3 days is preferred. NOTICE: If possible, we wish to begin these observations as early as 11-JUN-96, the beginning of the visibility window for EUVE. The EUVE constraint is accomplished with the requirement BETWEEN 11-JUN-96 AND 12-DEC-96. This constrain need only apply to the first visit. Observations of SS Cyg in outburst have been approved with XTE (Schlegel et al.; Wheatley et al.) and EUVE (Mauche et al.). These observations will be triggered by an alert by the AAVSO. The reaction time of XTE and EUVE to such an alert is typically significantly less than one day (i.e., significantly shorter than that of HST). Observations with both satellites will take place over a number of days: XTE observations will be obtained every 4 hrs for the first 2 days and every 8 hrs for next 12 days; EUVE observations will be quasi-continuous and could be obtained over a similar interval. Every attempt will be made to assure that X- ray and EUV observations are obtained simultaneously with the HST observations. We intend to obtain ground-based optical photometry of SS Cyg during the outburst observed by XTE, EUVE, and HST. These observations will be distributed over a number of days and be contributed by a number of individuals. When possible, optical observations will be obtained simultaneously with the HST observations. Co-Is J. Patterson (Columbia Univ.) and R. Robinson (Univ. of Texas) are committed to attempt to obtain simultaneous multicolor optical photometry in support of this campaign. The other optical observers who have expressed an interest in this campaign are as follows: T. Abbott (CFHT), co-I C. Haswell (Columbia Univ.), K. Horne (St. Andrews), S. Larsson (Stockholm Obs.), A. Shafter (San Diego State Univ.), P. Szkody (Univ. of Washington), G. Tovmassian (Univ. Nac. Auto. Mexico), and I. Voloshina (Moscow State Univ.). Additional observers will be recruited. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SS-CYGNI STAR, DWARF NOVA, RA=21H 42M 42.66S +/- 0.01S, 2000 V = 8.2+/-0.1 INTERACTING BINARY DEC=+43D 35' 09.5" +/- 0.1", B-V = 0.0+/-0.1 PLATE-ID=01KD F-CONT(1470)=2.5+/-0.5e-11 Comments: Dwarf nova; flux values apply at the peak of the outburst. Flux values at minimum are as follows: V=12.1+/-0.3, B-V= 0.4+/-0.3, F-CONT(1470)=2.0+/-1.0E- 13. V>9 on the plate, so the coordinates should be accurate. 6545( 8) - 06/10/96 17:22 - [ 5] Visit: 01 Visit Requirements: ON HOLD BETWEEN 11-JUN-96 AND 12-DEC-96 SCHED 90% On Hold Comments: Target of Opportunity Additional Comments: Visit Number 1 will be triggered by an alert by the AAVSO, and should take place within 3-5 days of the alert. Furthermore, Visit Number 1 must take place between 11-Jun-96 and 12-Dec-96 to allow simultaneous EUVE observations. Force use of low telemetry rate during the FOS exposures. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SS-CYGNI FOS/BL ACQ/PEA 4.3 G400H SCAN-STEP-Y=1.23,SEARCH-SIZE-X=1, 1 1 S ONBOARD ACQ FOR 2 K SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SS-CYGNI FOS/BL ACQ/PEA 1.0-PAI G400H SCAN-STEP-X=0.61,SCAN-STEP-Y=0.61 1 1 S ONBOARD ACQ FOR 3 K R-A ,SEARCH-SIZE-X=6,SEARCH-SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 3 SS-CYGNI FOS/BL ACQ/PEA 0.5-PAI G400H SCAN-STEP-X=0.29,SCAN-STEP-Y=0.29 1 1 S ONBOARD ACQ FOR 4 K R-A ,SEARCH-SIZE-X=3,SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 4 SS-CYGNI FOS/BL ACQ/PEA 0.25-PA G400H SCAN-STEP-X=0.11,SCAN-STEP-Y=0.11 1 1 S ONBOARD ACQ FOR 5-7 SAVE K IR-A ,SEARCH-SIZE-X=4,SEARCH-SIZE-Y=4 OFFSET 1 ------------------------------------------------------------------------------------------------------------------------------------ 5 SS-CYGNI FOS/BL RAPID 1.0-PAI G160L READ-TIME=1.0,SUB-STEP=1,COMB=YES 1 2600.0 NO SPLIT R-A ,STEP-PATT=SINGLE,STEP-TIME=0.128 ,DATA-RATE=LOW Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6 SS-CYGNI HRS RAPID 2.0 G140L 1515 SAMPLE-TIME=0.5 1 2480.0 NO SPLIT Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 7 SS-CYGNI HRS RAPID 2.0 G160M 1640.4 SAMPLE-TIME=0.5 1 2480.0 NO SPLIT Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 6] Visit: 02 Visit Requirements: AFTER 1 BY 1.5D TO 3D SCHED 90% ON HOLD On Hold Comments: Target of Opportunity Additional Comments: Force use of low telemetry rate during the FOS exposures. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SS-CYGNI FOS/BL ACQ/PEA 4.3 G400H SCAN-STEP-Y=1.23,SEARCH-SIZE-X=1, 1 1 S ONBOARD ACQ FOR 2 K SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 2 SS-CYGNI FOS/BL ACQ/PEA 1.0-PAI G400H SCAN-STEP-X=0.61,SCAN-STEP-Y=0.61 1 1 S ONBOARD ACQ FOR 3 K R-A ,SEARCH-SIZE-X=6,SEARCH-SIZE-Y=2 ------------------------------------------------------------------------------------------------------------------------------------ 3 SS-CYGNI FOS/BL ACQ/PEA 0.5-PAI G400H SCAN-STEP-X=0.29,SCAN-STEP-Y=0.29 1 1 S ONBOARD ACQ FOR 4 K R-A ,SEARCH-SIZE-X=3,SEARCH-SIZE-Y=3 ------------------------------------------------------------------------------------------------------------------------------------ 4 SS-CYGNI FOS/BL ACQ/PEA 0.25-PA G400H SCAN-STEP-X=0.11,SCAN-STEP-Y=0.11 1 1 S ONBOARD ACQ FOR 5-7 K IR-A ,SEARCH-SIZE-X=4,SEARCH-SIZE-Y=4 ------------------------------------------------------------------------------------------------------------------------------------ 5 SS-CYGNI FOS/BL RAPID 1.0-PAI G160L READ-TIME=1.0,SUB-STEP=1,COMB=YES 1 2600.0 NO SPLIT R-A ,STEP-PATT=SINGLE,STEP-TIME=0.128 ,DATA-RATE=LOW Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6 SS-CYGNI HRS RAPID 2.0 G140L 1515 SAMPLE-TIME=0.5 1 2480.0 NO SPLIT Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 7 SS-CYGNI HRS RAPID 2.0 G160M 1640.4 SAMPLE-TIME=0.5 1 2400.0 NO SPLIT Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 7] Visit: 03 Visit Requirements: AFTER 2 BY 1.5D TO 3D SCHED 90% ON HOLD On Hold Comments: Target of Opportunity Additional Comments: Force use of low telemetry rate during the FOS exposures. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SS-CYGNI FOS/BL RAPID 1.0-PAI G160L READ-TIME=1.0,SUB-STEP=1,COMB=YES 1 2400.0 USE OFFSET 1 NO SPLIT R-A ,STEP-PATT=SINGLE,STEP-TIME=0.128 ,DATA-RATE=LOW Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 2 SS-CYGNI HRS RAPID 2.0 G140L 1515 SAMPLE-TIME=0.5 1 2420.0 USE OFFSET 1 NO SPLIT Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 8] Visit: 04 Visit Requirements: AFTER 3 BY 1D TO 3D SCHED 90% ON HOLD On Hold Comments: Target of Opportunity Additional Comments: Force use of low telemetry rate during the FOS exposures. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SS-CYGNI FOS/BL RAPID 1.0-PAI G160L READ-TIME=1.0,SUB-STEP=1,COMB=YES 1 2400.0 USE OFFSET 1 NO SPLIT R-A ,STEP-PATT=SINGLE,STEP-TIME=0.128 ,DATA-RATE=LOW Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 2 SS-CYGNI HRS RAPID 2.0 G140L 1515 SAMPLE-TIME=0.5 1 2420.0 USE OFFSET 1 NO SPLIT Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 9] Visit: 05 Visit Requirements: AFTER 4 BY 1D TO 3D SCHED 90% ON HOLD On Hold Comments: Target of Opportunity Additional Comments: Force use of low telemetry rate during the FOS exposures. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SS-CYGNI FOS/BL RAPID 1.0-PAI G160L READ-TIME=1.0,SUB-STEP=1,COMB=YES 1 2400.0 USE OFFSET 1 NO SPLIT R-A ,STEP-PATT=SINGLE,STEP-TIME=0.128 ,DATA-RATE=LOW Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 2 SS-CYGNI HRS RAPID 2.0 G140L 1515 SAMPLE-TIME=0.5 1 2420.0 USE OFFSET 1 NO SPLIT Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 10] Visit: 06 Visit Requirements: AFTER 5 BY 1D TO 3D SCHED 90% ON HOLD On Hold Comments: Target of Opportunity Additional Comments: Force use of low telemetry rate during the FOS exposures. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SS-CYGNI FOS/BL RAPID 1.0-PAI G160L READ-TIME=1.0,SUB-STEP=1,COMB=YES 1 2400.0 USE OFFSET 1 NO SPLIT R-A ,STEP-PATT=SINGLE,STEP-TIME=0.128 ,DATA-RATE=LOW Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 2 SS-CYGNI HRS RAPID 2.0 G140L 1515 SAMPLE-TIME=0.5 1 2420.0 USE OFFSET 1 NO SPLIT Comments: Expand exposure to pack orbit. ------------------------------------------------------------------------------------------------------------------------------------ 6545( 8) - 06/10/96 17:22 - [ 11] Summary Form for Proposal 6545 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SCAN-STEP-Y=1.23 SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SEARCH-SIZE-Y=2 SEARCH-SIZE-X=3 SEARCH-SIZE-Y=4 DATA-RATE=LOW SAMPLE-TIME=0.5 SEARCH-SIZE-X=6 SCAN-STEP-Y=0.29 SEARCH-SIZE-X=4 STEP-TIME=0.128 STEP-PATT=SINGLE COMB=YES SUB-STEP=1 READ-TIME=1.0 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category BINARIES AND STAR FORMATION ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ON HOLD BETWEEN 11-JUN-96 AND 12-DEC-96 SCHED 90% ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 4 ONBOARD ACQ FOR 5-7 SAVE OFFSET 1 NO SPLIT AFTER 1 BY 1.5D TO 3D SCHED 90% ON HOLD ONBOARD ACQ FOR 5-7 AFTER 2 BY 1.5D TO 3D SCHED 90% ON HOLD USE OFFSET 1 NO SPLIT AFTER 3 BY 1D TO 3D SCHED 90% ON HOLD AFTER 4 BY 1D TO 3D SCHED 90% ON HOLD AFTER 5 BY 1D TO 3D SCHED 90% ON HOLD ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G400H G160L G140L G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names SS-CYGNI ------------------------------------------------------------------------------------------------------------------------------------