It is believed that the most massive stars do not exceed ~150 Msol initially, as was derived from the observed cut-off of the initial-mass function (IMF) of the Arches cluster, the most massive, unevolved cluster in the Milky Way. However, recent results by Crowther et al. suggest that the cut-off occurs more likely around 300 Msol. A crucial role in their study plays NGC3603, the most massive, visible, Galactic starburst cluster, that harbors three stars with initial masses higher than any of the Arches stars. However, these findings rely entirely on A1, a binary whose components have very ill-constrained masses, 116 +/- 31 Msol and 89 +/- 16 Msol, respectively. While Crowther et al.'s conclusion thus are possibly wrong, A1 is the only known double-eclipsing system whose components potentially have masses >100 Msol, and whose nearly complete set of orbital and stellar parameters can be derived essentially model-independently. We therefore propose to use HST/STIS to obtain, for the first time, repeated, high-quality, far-ultraviolet and optical spectroscopy and photometry, to fully constrain, in the most self-consistent manner possible, masses, temperatures, radii, luminosities and distance of A1, with an accuracy of ~5-10%. Both components of A1 will be modeled using the latest atmosphere and evolutionary codes, to calibrate the mass-luminosity relation in the highest mass regime currently accessible to direct observations. Our study will also settle whether the Arches is suited to investigate the upper end, any putative cut-off, of the IMF, with far-reaching consequence for our understanding of massive-star formation. This program does phase, time-critical, repeated UV/VIS spectroscopy and VIS imaging of a very massive binary in the core NGC3603-A1. It is the brightest star in the field, and a WN6ha+WN6ha double-eclipsing binary with P=3.7723 days (or ~56.5845 HST orbits). Observing strategy is to visit A1 every 4 +/- 1 HST orbits, to cover the binary phase as equidistantly as possible by ~1/14, i.e. ~0.07 in phase. This will allow to obtain both good RV and lightcurves. PHASE constraints have been given accordingly, allowing a phase margin that corresponds to a plus/minus ~1 HST orbit margin. Since accumulated period and zero-phase (E0) uncertainties are an issue (also raised in the panel report), we have grouped visits 2 through 14 together so that they are observed during the visibility period that occurs in January 2012. Observing the binary within a very short time (rather than spreading out the phased visits over the whole of Cycle 19), combined with the ~equidistant sampling, should practically rid us of the impact of accumulated errors. However, this leads to pretty severe scheduling constraints. If they prove to be unfeasible, we accept to drop the BETWEEN and AFTER constraints for visits 02 through 14, since there is another, ~4-week long visibility period in June/July 2012, offering much more scheduling flexibility. To also catch the two other WN6ha stars, B and C, the slit will be aligned using the ORIENT constraints (cf. Additional Comments). Star C is an SB1 binary with P~8.9 days, so the idea is to detect its hitherto unseen companion and (possibly shallow) eclipses. While B is observed only once (visit 01), C will be observed during visits 02 through 14. Star B is the most luminous star in the cluster, but could be a long-period binary. Since there is an archival STIS spectrum from Cycle 17, we intend to take a spectrum during one visit (#1), to detect possible RV variations between the two spectra and thus have an indication of B's binary status on those timescales. A 3(4)-position dithering is utilized for all spectroscopy (imaging), to improve CR and bad-pixel rejection, and increase the final S/N (flat-field quality). For imaging, we attempt an integer-pixel dither pattern. CHANGES FROM PHASE I a) Due to a mishap in Phase I, overheads were grossly mis-calculated. As a consequence, we had to adjust our observing stategy: rather than have optical + FUV spectroscopy in all 14 visits, we have now 2 dedicated UV visits (#6 and #11). Optical imaging precedes the FUV spectroscopy, and is well within the 30min time limit for same-orbit optical-UV observations. The remaining 12 visits are purely optical visits (imaging and spectroscopy). b) Instead of the LP28x50 filter specified in Phase I, we employ the 50CCD filter. This allows us to couple our imaging to existing archival imaging. GAIN=1 has been selected for better quality (bias issues), and all count rates are within 70% of the full well (ETC-ID STIS.im.185745). ISSUES WITH THE BRIGHT-TARGET LIMIT For our three target stars, Crowther et al. (2010, MNRAS, 408, 731) recently have modeled the UV fluxes. From their Fig 2. follows that even the UV-brightest target's flux does not exceed F(1640)~3.2e-14 erg/s/cm2/A. Using a conservative throughput of the 52x0.2 aperture of 75%, we thus obtain a flux of 2.4e-14 erg/s/cm2/A on the detector, i.e. ~200 times below the limit for point sources which is 5.0e-12erg/s/cm2/A (from Table 13.44 of the STIS IHB). As can also be seen from Fig.2, the UV flux drops for longer wavelengths, thus effectively compensating for the increasing throughput of the aperture redwards of 1800 A. However, issues with field stars remain. While all O stars in the field are visually fainter than our target stars by at least 1mag, they might be hotter, and thus effectively as UV-bright as (or brighter than). After deadline of Phase II, we will provide FUV flux estimates for the brightest of the hottest O stars in the field, by using CMFGEN model atmospheres, published B- and V-band magnitudes, and E(B-V)=1.39. All target coordinates where obtained from an archival STIS image (ob1505mbq_x2d.fits; Prog-ID 11626; PI Massey). Position angles between A1 and C: 123.5 / 303.5 pm 1.0 deg A1 and B: 147.5 / 327.5 pm 1.5 deg were calculated using this STIS frame and verified with the Aladin Previewer. HOT STARS 12 false 0.0 0.0 false false false false SUPPORTED STAR WOLF RAYET - WN Target star in a crowded field, hence acquired by SAM after peak-up of an offset star (Sher 25).All coordinates are retrieved from a STIS frame (ob1505mbq_x2d.fits, ProgID 11626, PI: Massey) to ensure maximum consistency for small-angle manoeuver. J2000 J2000 STAR B0-B2 III-I Offset star for peak-up acquisition. All coordinates are retrieved from a STIS frame (ob1505mbq_x2d.fits, ProgID 11626, PI: Massey) to ensure maximum consistency for small-angle manoeuver. SHER25 J2000 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/CCD Imaging No No F28X50LP STIS/CCD Spectroscopic No No G430M 3936 STIS/CCD Spectroscopic No No G430M 4706 STIS/CCD Spectroscopic No No G750M 7283 STIS/FUV-MAMA Spectroscopic No No G140L 1425 POS-TARG DITHER 3 LINE false false 3 90.0 STIS-ALONG-SLIT 1 false POS-TARG DITHER 0.567 10 pixels are 0.5078 arsec. LINE 0.567 false false 143.130102 4 26.6 STIS-CCD-BOX 3 false The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 01 (optical A1 and B) from phase 0.053 to 0.088. Scheduled to be executed on January 23, 2012, the only visibility in Cycle 19 that meets both PHASE and ORIENT constraints. (Tic-Visit :proposal-id 12615 :visit-id "01" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:30.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 02 (optical A1 and C) from phase 0.088 to 0.124 Visits 2 through 13 are to be executed within the 4-week visibility period in June/July 2012. THese visits are thus grouped together. 1340054501000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "02" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:34.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 03 (optical A1 and C) from phase 0.159 to 0.194 1341383829000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "03" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:37.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 04 (optical A1 and C) from phase 0.230 to 0.265 1340424106000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "04" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 05 (ultraviolet A1 and C) from phase 0.300 to 0.336 (after quadrature) 1341751390000 124.5 (Tic-Visit :proposal-id 12615 :visit-id "05" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 300192 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3183 :al-overhead-at-end 0 :internal-dur-at-end 452 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 06 (optical A1 and C) from phase 0.371 to 0.406 1339824951000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "06" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:45.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 07 (optical A1 and C) from phase 0.442 to 0.477 1339837169000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "07" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:48.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 08 (optical A1 and C) from phase 0.513 to 0.548 1340191970000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "08" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:51.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "08" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 09 (optical A1 and C) from phase 0.583 to 0.612 1340539082000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "09" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:54.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "09" :obset-id "09" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "09" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 10 (ultraviolet A1 and C) from phase 0.654 to 0.689 (before quadrature) 1340238084000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "10" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:56.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 300192 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "10" :obset-id "10" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "10" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3183 :al-overhead-at-end 0 :internal-dur-at-end 452 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 11 (optical A1 and C) from phase 0.725 to 0.760 1340262086000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "11" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:56:59.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "11" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 12 (optical A1 and C) from phase 0.795 to 0.831 1340282614000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "12" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:57:01.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "12" :obset-id "12" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "12" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 13 (optical A1 and C) from phase 0.866 to 0.901 1339980528000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "13" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:57:04.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "13" :obset-id "13" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "13" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. Visit 14 (optical A1 and C) from phase 0.937 to 0.972 1340003218000 122.5 (Tic-Visit :proposal-id 12615 :visit-id "14" :proposal-version -1 :trans-version "20110509" :date "11-Aug-2011 08:57:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 331664 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12615 :visit-id "14" :obset-id "14" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12615 :visit-id "14" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3181 :al-overhead-at-end 0 :internal-dur-at-end 789 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3516 :pcs-gap 0 ) false 1 0 Snapshot exposures with very good S/N for high-precision differential photometry. All count rates OK. Acquisition of Sher 25