0 Assigned ID: 5833 ----- Attempting Submission 1 (Tue Mar 26 23:30:35 GMT 2024) ----- ORBITAL VISIBILITY OVERRUN ORBITAL VISIBILITY OVERRUN ORBITAL VISIBILITY OVERRUN ORBITAL VISIBILITY OVERRUN ORBITAL VISIBILITY OVERRUN ORBITAL VISIBILITY OVERRUN Second submission of Phase II for GO-17744. The special requirement explicitly setting 53 minutes of visibility has been removed, leaving around 52 min and 30 seconds of visibility in each orbit. The new program shows no errors or warnings. We would appreciate it if the instrument specialist would review the question of whether or not to use a post-flash in our mosaic, which is occupied by the disk of M 82 in much of its area. Third submission of Phase II. New visits 51 and 52 added to include new images awarded by HOPR request. POSTARGS of these repeat images adjusted to keep chip gaps from overlapping with previous images in Visits 01 and 02, given the potential of using ORIENT=305--315 in Fall 2025. Fourth submission of Phase II. New visits 53 and 55 added to include new images awarded by new HOPR requests. POSTARGS of these repeat images adjusted to keep chip gaps from overlapping with previous successful images in Visits 03 and 05, given the potential of using ORIENT 309--311 in Fall 2026. If scheduled in Spring 2027, we will need to re-adjust the POSTARGS. All error messages only apply to the completed visits 01--06, new Visits 53 and 55 seem okay. 850655446 ----- Attempting Submission 1 (Tue Aug 06 18:47:40 GMT 2024) ----- HST Phase II Proposal 17744 successfully submitted. Receipt: # 17744-1 ----- Attempting Submission 2 (Sun Aug 11 15:46:12 GMT 2024) ----- ----- Attempting Submission 3 (Sat Jul 26 18:03:06 GMT 2025) ----- ----- Attempting Submission 4 (Thu Jul 02 22:02:59 GMT 2026) ----- The Visit Planner was run successfully on the new visits 53 and 55. All errors relate to already executed visits 01--06 Messier 82 (M82, NGC 3034) is the famous "Cigar Galaxy'' undergoing a starburst just 3.5 Mpc away. A spectacular mosaic of the entire galaxy was created by ACS 20 years ago. Here we propose to search for undiscovered light echoes from supernovae (SNe) that exploded as much as 500 years ago. M82 is an active star-forming galaxy expected to host, on average, one SN every ten to twenty years (and has hosted 3 since 2004!). Dust is important for generating light echoes, and M82 has dust distrubuted throughout and above its stellar disk. Even supernovae hidden from our direct view by dust can reveal themselves by illuminating dust in unobscurred directions. Three confirmed SN eruptions have been detected in M82 in the past 20 years. The most recent Ia event, SN 2014J, has a well detected light echo and provides an excellent proof-of-concept for our proposed survey. Our goal is to use HST to detect 15--20 light echoes in M82 via their resolved shapes and rapid proper motions, following Rest et al. (2005). The proper motion vectors will allow us to pair a sub-set of them with known X-ray, optical and radio supernova remnants in M82. Our survey will effectively double the sample of recent extragalactic SNe echoes, and potentially quadruple the number of echoes from historical SNe that erupted prior to the 20th century. This LE sample is the necessary first step to then use HST or ground-based telescopes to obtain spectra of the brighter LEs and thereby classify their parent SNe, creating an unprecedented demographic survey of SNe in a starburst galaxy over the last few centuries---a survey not obtainable by any other means. Summary: We will use six orbits with the ACS/WFC and the WFCENTER two-chip readout to exactly re-create the DD-10776 3 x 2 element mosaic of starburst galaxy M 82 in the F555W filter, in order to perform difference imaging with a 19-year baseline and search for light echoes from historic supernovae. We specifically use the same instrument, the same filter, the same six fixed targets for the mosaic elements, the same ORIENT=130 requirement, and essentially the identical dither POS TARG offsets as the DD-10776 mosaic. For maximum scheduling flexibility we divide our six orbits into six visits, collecting five ~387-second exposures/dither positions in each mosaic element. The only minor changes we make are to use five dithers (instead of four), which serves to improve signal in the chip gaps and mitigate pixels lost to the saturation bleeding from the bright (V=10.0) star BD +70 587 (which is imaged two mosaic elements). Total exposures times across five ~387-second exposures in each orbit are around 1935 seconds. APT reports that all six of these one-orbit visits can be scheduled within an 8-day visibility window in late March 2025. If this too restrictive, we could broaden the orientation requirement slightly to increase the visibility window but would prefer to keep the new mosaic as identical as possible to the archival one. Detailed description: Our proposed and awarded goal is to create a survey of as many historical SNe in M82 as possible by obtaining a new HST imaging epoch exactly matched to an earlier ACS mosaic to search for their light echoes. The program DD-10776 in Cycle 14 used ACS/WFC in a 9.6 x 6.4 arcmin mosaic to essentially record all of M82 in deep B, V , I, and H-alpha images. As reflections of SNe near maximum, LE are brightest in B and V, and are much fainter in bluer or redder filters. Despite 15 other GO imaging programs on M82, none produce a set of deep images that simultaneously 1) use identical B or V filters from either ACS or WFC3, 2) cover more than 30% of the DD-10776 mosaic, and 3) span at least 11 years between epochs (producing >4 HST pixel shifts). All 2014J follow-up has used the WFC3 filters or ACS polarizers, and nearly all with very small sub-apertures. Large residuals remain when subtracting images taken in similar, but slightly different, filters (for example ACS/F555W versus WFC3/F555W). We will obtain ACS F555W (V-band) imaging to exactly match the pointings from the original 2006 mosaic. The instrument+filter matching is very important, as even extremely similar filters produce highly structured backgrounds during difference imaging. Using the same pointings and roll angle will maximize the overlap for image subtractions and match the distortion corrections to increase the LE detection efficiency. SNe spectra peak around 500 nm at maximum and ACS V is more sensitive than B and less sensitive to extinction. So, for the sake of orbit efficiency, we use F555W as our single survey filter. DD-10776 needed 4 orbits per pointing with most of the time spent in exposing the H-alpha filter. We require only one orbit per pointing to reach slightly deeper in the F555W filter. To help filter cosmic rays and chip defects, each orbit is divided into five exposures at five dithered positions, closely following the DD-10776 dithers. Our dither POS TARGs combine a large three-point line dither to span the chip gap with small two-point sub-pixel dithers. DD-10776 used four F555W dithered exposures at each mosaic element; we use five by exactly replicating their four dithers and adding a third chip-gap-spanning dither. In this way any sky pixel that falls in a chip gap in one exposure is imaged in at least three others. In the DD-10776 images, mosaic elements at M82-POS3 and M82-POS4 included the 10th magnitude star BD +70 587, which saturated and bled down over 300 pixels across four columns. Our individual exposures will be about 15% longer and would bleed even further. To help mitigate this and recover real data in the bled columns, we use just three of the original DD-10776 dithers in these two mosaic elements and add a pair of sub-pixel dithered images at a large enough chip-gap-spanning offset to exclude BD +70 587 from these two images. The ACS ETC predicts that typical sky backgrounds will provide around 27 electrons per pixel. While this is just slightly below the 30 electron threshold for the recommendation for the use of a post-flash, we note that M 82 fills much of the imaged region and the ETC also predicts that a galactic background surface brightness in V band any brighter than 24.2 magnitudes/arcsec^2 (or equivalently 7 x 10^-19 erg/cm^2/sec/angstrom/arcsec^2) will be enough to raise the per pixel electron signal to 30. ACS or WFC3: For maximum science return on our proposal it is very important, although not absolutely critical, to use ACS/WFC and its F555W filter. The F555W filter on WFC3/UVIS has reduced throughput and a much broader bandpass, which would introduce significant structured noise into difference images between it and the 2006 ACS mosaic. Also, the full disc of M 82 has never been imaged in any WFC3 broadband filter. We are aware that one of the proposed solutions to the STScI budget is to decommission the ACS in favor of WFC3. As instructed by our contact scientist, we have structured our Phase II proposal under the assumption that ACS will be available for all of Cycle 32 and have thus replicated the DD-10776 mosaic down to its fixed targets, strict orientation, and POS TARG dithers. If ACS should be decommissioned after Cycle 32 starts, but before our March 2025 visibility window, we request that we be allowed to re-orient and re-structure our mosaic so that the orbits can be scheduled before ACS is mothballed. If ACS is decommissioned before Cycle 32 even begins, we request that our orbits be shifted to WFC3 and that we be given the flexibility to choose different mosaic positions and different, possibly multiple, WFC3 filters to best match the existing archival WFC3 imaging of M 82. Our team has extensive experience with supernovae, supernova remnants, and light echoes, and is similarly accomplished with the planning and execution of HST observations, as well as sophisticated difference imaging data reduction techniques. Wood has recently written code to model light echo surface brightness and colors to extract dust properties. Lawrence has been PI on 4 HST GO or AR programs and Co-I on 41 more. Garnavich has been PI on 16 HST programs and Co-I on 65 more. Wood is a postdoc who is PI on a current HST AR project on light echoes and CO-I on a current GO project on supernovae. Rest has been PI on 6 HST programs and Co-I on 55 more. Lawrence has been lead author on 2 and co-author on 22 peer-reviewed articles, most involving HST data analysis, supernovae, and/or light echoes. Garnavich has been first author on 31 and co-author on more than 260 peer-reviewed articles. Wood has been lead author on one peer-reviewed paper and co-author on 7 other peer-reviewed articles. Rest has been lead author on 14 and co-author on more than 290 peer-reviewed articles. Rest has discovered light echoes of ancient SNe in the LMC, Cas A, Tycho, and the Great Eruption of Eta Car, and classified their SNe with spectroscopy. Stellar Physics and Stellar Types Stellar Populations and the Interstellar Medium 6 false false false false false false false SUPPORTED GALAXY SEYFERT STARBURST Our proposal is to redo the DD-10776 ACS/WFC six-element mosaic of M82 from 2006 as exactly as possible. This target information is copied as closely as possible from the DD-10776 Phase II file for Position 1, the NE corner of their 3 x 2 element mosaic of M 82. J2000 J2000 GALAXY SEYFERT STARBURST Our proposal is to redo the DD-10776 ACS/WFC six-element mosaic of M82 from 2006 as exactly as possible. This target information is copied as closely as possible from the DD-10776 Phase II file for Position 2, the N central region of their 3 x 2 element mosaic of M 82. J2000 J2000 GALAXY SEYFERT STARBURST Our proposal is to redo the DD-10776 ACS/WFC six-element mosaic of M82 from 2006 as exactly as possible. This target information is copied as closely as possible from the DD-10776 Phase II file for Position 3, the NW corner of their 3 x 2 element mosaic of M 82. J2000 J2000 GALAXY SEYFERT STARBURST Our proposal is to redo the DD-10776 ACS/WFC six-element mosaic of M82 from 2006 as exactly as possible. This target information is copied as closely as possible from the DD-10776 Phase II file for Position 4, the SW corner of their 3 x 2 element mosaic of M 82. J2000 J2000 GALAXY SEYFERT STARBURST Our proposal is to redo the DD-10776 ACS/WFC six-element mosaic of M82 from 2006 as exactly as possible. This target information is copied as closely as possible from the DD-10776 Phase II file for Position 5, the S central region of their 3 x 2 element mosaic of M 82. J2000 J2000 GALAXY SEYFERT STARBURST Our proposal is to redo the DD-10776 ACS/WFC six-element mosaic of M82 from 2006 as exactly as possible. This target information is copied as closely as possible from the DD-10776 Phase II file for Position 6, the SE corner of their 3 x 2 element mosaic of M 82. J2000 J2000 ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F555W ACS/WFC Imaging No No F555W 1783027833898 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v01.xml First orbit, First mosaic position (M82-POS1, NE corner): Four of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the F555W exposures in Visits 11--14 of DD-10776, plus a fifth, more southern, chip-gap-spanning dither postion to provide at least three exposures in every pixel falling in a chip gap. 1742798912000 130.0 (Tic-Visit :proposal-id 17744 :visit-id "01" :proposal-version -1 :trans-version "20260319" :date "02-Jul-2026 17:30:33.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1421120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2770 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 1 New dither position with a negative/southward, basic chip-gap-spanning dither offset from the fixed target (position #2 in this visit), with POS TARGS -0.247", -2.84". This fifth, extra dither (relative to the four dithers in 2006) provides for at least three exposed pixels in every chip gap. Using a downward dither relative to the fixed target pointing in mosaic elements 1 & 2 allows for more total integration time in central portions of the galaxy disk in the overlap zones with mosaic elements 5 & 6. Putting it first in the exposure sequence minimizes overhead time lost to the pointing maneuvers. Default pointing on fixed target with no dither, exactly identical to DD-10776 dither position #1 Small 2-point sub-pixel dither offset from position #2 with POS TARGS +0.124", +0.084", identical to DD-10776 dither position #2 Basic chip-gap-spanning dither dither offset from position #2 with POS TARGS +0.247", +2.84" , identical to DD-10776 dither position #3 Small 2-point sub-pixel dither offset from position #4 with POS TARGS +0.371", +3.068", identical to DD-10776 dither position #4 1783027834033 53.0 The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v51.xml First orbit, First mosaic position (M82-POS1, NE corner): Four of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the F555W exposures in Visits 11--14 of DD-10776, plus a fifth, more southern, chip-gap-spanning dither postion to provide at least three exposures in every pixel falling in a chip gap. HOPR repeat of visit 01, exposure 5 1760457743000 309.9271984772309 (Tic-Visit :proposal-id 17744 :visit-id "51" :proposal-version -1 :trans-version "20260319" :date "02-Jul-2026 17:30:34.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 284224 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "51" :obset-id "51" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "51" :orbit-number 1 :pcs-time 380 :si-vis-utilization 602 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 0 Small 2-point sub-pixel dither offset from position #4 with POS TARGS +0.371", +3.068", identical to DD-10776 dither position #4 1783027834364 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v02.xml Second orbit, second mosaic position (M82-POS2, N central region): Four of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the F555W exposures in Visits 21--24 of DD-10776, plus a fifth, more southern, chip-gap-spanning dither postion to provide at least three exposures in every pixel falling in a chip gap. 1743217497000 130.0 (Tic-Visit :proposal-id 17744 :visit-id "02" :proposal-version -1 :trans-version "20260319" :date "02-Jul-2026 17:30:34.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1421120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2770 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 1 New dither position with a negative/southward, basic chip-gap-spanning dither offset from the fixed target (position #2 in this visit), with POS TARGS -0.247", -2.84". This fifth, extra dither (relative to the four dithers used in DD-10776) provides for at least three exposed pixels in every chip gap. Using a downward dither relative to the fixed target pointing in mosaic elements 1 & 2 allows for more total integration time in central portions of the galaxy disk in the overlap zones with mosaic elements 5 & 6. Putting it first in the exposure sequence minimizes overhead time lost to the pointing maneuvers. Default pointing on fixed target with no dither, exactly identical to DD-10776 dither position #1 Small 2-point sub-pixel dither offset from position #2 with POS TARGS +0.124", +0.084", identical to DD-10776 dither position #2 Basic chip-gap-spanning dither dither offset from position #2 with POS TARGS +0.247", +2.84" , identical to DD-10776 dither position #3 Small 2-point sub-pixel dither offset from position #3 with POS TARGS +0.371", +3.068", identical to DD-10776 dither position #4 1783027834493 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v52.xml Second orbit, second mosaic position (M82-POS2, N central region): Four of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the F555W exposures in Visits 21--24 of DD-10776, plus a fifth, more southern, chip-gap-spanning dither postion to provide at least three exposures in every pixel falling in a chip gap. HOPR repeat of visit 02, exposure 4. 1760633048000 308.2300362269584 (Tic-Visit :proposal-id 17744 :visit-id "52" :proposal-version -1 :trans-version "20260319" :date "02-Jul-2026 17:30:34.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 284224 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "52" :obset-id "52" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "52" :orbit-number 1 :pcs-time 380 :si-vis-utilization 602 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 0 Basic chip-gap-spanning dither dither offset from position #2 with POS TARGS +0.247", +2.84" , identical to DD-10776 dither position #3 1782851118655 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v03.xml Third orbit, third mosaic position (M82-POS3, NW corner): Three of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the three F555W exposures in Visits 31--33 of DD-10776, plus two exposures/dithers in a 2-point sub-pixel dither pair that are shifted by 4x the standard chip-gap-spanning dither with POS TARGs of +0.988, +11.936 and +1.112, +12.020 arcseconds. These fourth and fifth dither positions i) primarily avoid a bright 10th magnitude star (BD +70 587) near the bottom of the aperture that saturated and bled over more than 300 pixels across four columns in the DD-10776 images, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new northern strip at the top of the aperture that wasn't sampled in 2006. The two new dither postions come last in the orbit to save overhead time from the pointing maneuvers. Using the pixel coordinates of the saturated star in the 2006 Visit 31 drizzled (_drc) images, the POS TARGs for dithers 4 & 5 here should place the star at least 2.8 arcseconds/55 pixels off the bottom of the CCD. 1774758834000 130.0 (Tic-Visit :proposal-id 17744 :visit-id "03" :proposal-version -1 :trans-version "20260319" :date "30-Jun-2026 16:25:18.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1421120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "03" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2771 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 1 Default pointing on fixed target with no dither, exactly identical to DD-10776 dither position #1 in Visit 31 Small 2-point sub-pixel dither offset from position #1 with POS TARGS +0.124", +0.084", identical to DD-10776 dither position #2 in Visit 32 Basic chip-gap-spanning dither dither offset from position #1 with POS TARGS +0.247", +2.984" , identical to DD-10776 dither position #3 in Visit 33 New dither position with a positiive/northward, 4x multiple of the basic chip-gap-spanning dither, with POS TARGS +0.988", +11.936". The fourth and fifth dither positions in this orbit i) primarily avoid a bright 10th magnitude star (BD +70 587) near the bottom of the aperture that saturated and bled along more than 300 pixels across four columns in the DD-10776 images, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new northern strip at the top of the aperture that wasn't imaged in 2006. New dither position with a positiive/northward, 4x multiple of the basic chip-gap-spanning dither plus a 2-point sub-pixel dither, with net POS TARGS +1.112", +12.020". The fourth and fifth dither positions in this orbit i) primarily avoid a bright 10th magnitude star (BD +70 587) near the bottom of the aperture that saturated and bled along more than 300 pixels across four columns in the DD-10776 images, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new northern strip at the top of the aperture that wasn't imaged in 2006. 1783028488811 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v53.xml NEW VISIT 53 IS A FULL REPEAT OF MOSTLY FAILED VISIT 03, AWARDED FIVE NEW EXPOSURES Third orbit, third mosaic position (M82-POS3, NW corner): Given that the two successful exposures in Visit 03 both fully incorporate the bright star at the bottom (SE) edge of the field of view, the five new exposures here are positioned to give two more images sampling the bright star on the chip (exposures 01 & 02), while the remaining three are shifted slighyt NW to avoid the star and allow us to cleanly sample the underlying galaxy lost to the saturated columns and also place the chip gaps differently from the successful Visit 03 exposures. If scheduled for a Fall 2026 execution, the optimal orienation is around 310 degrees. The orient range from 309--311 degrees chosen here keeps the inverted footprint very similar to the original March 2006 and March 2026 images, expands the schedulability windows, and avoids overlaps of the chip gap with the two successful Visit 03 exposures. If this new visit cannot be scheduled in Fall 2026, we will need to adjust the POSTARGS to achieve the same goals for a 130 degree orient in Sping 2027. Original description of Visit 03: Three of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the three F555W exposures in Visits 31--33 of DD-10776, plus two exposures/dithers in a 2-point sub-pixel dither pair that are shifted by 4x the standard chip-gap-spanning dither with POS TARGs of +0.988, +11.936 and +1.112, +12.020 arcseconds. These fourth and fifth dither positions i) primarily avoid a bright 10th magnitude star (BD +70 587) near the bottom of the aperture that saturated and bled over more than 300 pixels across four columns in the DD-10776 images, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new northern strip at the top of the aperture that wasn't sampled in 2006. The two new dither postions come last in the orbit to save overhead time from the pointing maneuvers. Using the pixel coordinates of the saturated star in the 2006 Visit 31 drizzled (_drc) images, the POS TARGs for dithers 4 & 5 here should place the star at least 2.8 arcseconds/55 pixels off the bottom of the CCD. (Tic-Visit :proposal-id 17744 :visit-id "53" :proposal-version -1 :trans-version "20260319" :date "02-Jul-2026 17:41:28.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1421120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "53" :obset-id "53" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "53" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2711 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 0 Default pointing on fixed target with no dither, exactly identical to DD-10776 dither position #1 in Visit 31 Small 2-point sub-pixel dither offset from position #1 with POS TARGS +0.124", +0.084", identical to DD-10776 dither position #2 in Visit 32 Basic chip-gap-spanning dither dither offset from position #1 with POS TARGS +0.247", +2.984" , identical to DD-10776 dither position #3 in Visit 33 New dither position with a positiive/northward, 4x multiple of the basic chip-gap-spanning dither, with POS TARGS +0.988", +11.936". The fourth and fifth dither positions in this orbit i) primarily avoid a bright 10th magnitude star (BD +70 587) near the bottom of the aperture that saturated and bled along more than 300 pixels across four columns in the DD-10776 images, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new northern strip at the top of the aperture that wasn't imaged in 2006. New dither position with a positiive/northward, 4x multiple of the basic chip-gap-spanning dither plus a 2-point sub-pixel dither, with net POS TARGS +1.112", +12.020". The fourth and fifth dither positions in this orbit i) primarily avoid a bright 10th magnitude star (BD +70 587) near the bottom of the aperture that saturated and bled along more than 300 pixels across four columns in the DD-10776 images, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new northern strip at the top of the aperture that wasn't imaged in 2006. 1783027834815 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v04.xml Fourth orbit, fourth mosaic position (M82-POS4, SW corner): Three of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the three F555W exposures in Visits 41--43 of DD-10776, plus two exposures/dithers in a 2-point sub-pixel dither pair that is shifted by 4x the standard chip-gap-spanning dither with POS TARGs of -0.247, -2.984 and -0.371, -0.3.068 arcseconds. These two new dither positions i) primarily avoid a bright 10th magnitude star near the top of the aperture that saturated and bled over more than 300 pixels across four columns in the 2006 pointing, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new northern strip at the top of the aperture that wasn't sampled in 2006. The two new dither postions come first in the orbit to save overhead time from the pointing maneuvers. Using the pixel coordinates of the saturated star in the 2006 Visit 43 drizzled (_drc) images, the POS TARGs for dithers 1 & 2 here should place the star at least 2.8 arcseconds/55 pixels off the bottom of the CCD. 1774747698000 130.0 (Tic-Visit :proposal-id 17744 :visit-id "04" :proposal-version -1 :trans-version "20260319" :date "02-Jul-2026 17:30:34.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1421120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "04" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2770 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 1 New dither position with a negative/southward, basic chip-gap-spanning dither offset from the fixed target (position #3 in this visit), with POS TARGS -0.247", -2.984". The new first and second dither positions in this orbit i) primarily avoid a bright 10th magnitude star (BD +70 587) near the top of the aperture that saturated and bled along more than 300 pixels across four columns in the 2006 pointing, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new southern strip at the bottom of the aperture that wasn't imaged in 2006. New dither position with a negative/southward, basic chip-gap-spanning dither plus a small 2-point sub-pixel dither offset from position #1, with POS TARGS -0.371", -3.068". The first and second dither positions in this orbit i) primarily avoid a bright 10th magnitude star (BD +70 587) near the top of the aperture that saturated and bled along more than 300 pixels across four columns in the 2006 pointing, but also ii) provide for at least three exposures in every pixel in the chip gap, and also iii) provide for at least two exposures in nearly every pixel in the new southern strip at the bottom of the aperture that wasn't imaged in 2006. Default pointing on fixed target with no dither, exactly identical to DD-10776 dither position #1 from Visit 41 Small 2-point sub-pixel dither offset from position #2 with POS TARGS +0.124", +0.084", identical to DD-10776 dither position #2 from Visit 42 Basic chip-gap-spanning dither dither offset from position #2 with POS TARGS +0.247", +2.84" , identical to DD-10776 dither position #3 from Visit 43 1782851508262 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v05.xml Fifth orbit, fifth mosaic position (M82-POS5, S central region): Four of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the F555W exposures in Visits 51--54 of DD-10776, plus a fifth, more northern, chip-gap-spanning dither postion to provide at least three exposures in every pixel falling in a chip gap. 1774753200000 130.0 (Tic-Visit :proposal-id 17744 :visit-id "05" :proposal-version -1 :trans-version "20260319" :date "30-Jun-2026 16:31:48.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1421120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "05" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2770 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 1 Default pointing on fixed target with no dither, exactly identical to DD-10776 dither position #1 Small point dither offset from position #1 with POS TARGS +0.124", +0.084", identical to DD-10776 dither position #2 Gap closing dither offset from position one with POS TARGS +0.247", +2.984" , identical to DD-10776 dither position #3 Small point dither offset from position #4 with POS TARGS +0.371", +3.068", identical to DD-10776 dither position #4 New dither position with a positiive/northward, chip-gap-spanning dither, with POS TARGS +0.494", +5.968". This fifth dither (relative to the four dithers in DD-10776) provides for at least three exposed pixels in every chip gap. Using a posittive dither relative to the fixed target pointing in mosaic elements 5 & 6 allows for more total integration time in central portions of the galaxy disk in the overlap zones with mosaic elements 1 & 2. Putting it last in sequence minimizes overhead time lost to the pointing maneuvers. 1783028484783 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v55.xml REPEAT OF FIRST EXPOSURE OF VISIT 05 ONLY: Fifth orbit, fifth mosaic position (M82-POS5, S central region): Repeat of first exposure from Visit 05 that was corrupted by multiple satellite streaks. When scheduled at the 180-degree opposite orientation from the original (in Fall 20026), the orient range of 310.0 degrees +/-1.0 degrees and the new postargx,y values of -0.494, -5.968 arcseconds allow for nearly identical overlap with the original image footprint, but more importantly, it places the chip gap completely with no overlap of the previous four successful images. As a bonus, it is further from the wings of the PSF and diffraction spikes of the bright star at the southern edge. Adding +/-1 degree in the orient allows for an expanded schedulability window in Fall 2026. If the visit cannot be scheduled in Fall 2026, we will likely need to adjust the orient and postargs for a visit scheduled in Spring 2027. (Tic-Visit :proposal-id 17744 :visit-id "55" :proposal-version -1 :trans-version "20260319" :date "02-Jul-2026 17:41:24.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 284224 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "55" :obset-id "55" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "55" :orbit-number 1 :pcs-time 380 :si-vis-utilization 602 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 0 Default pointing on fixed target with no dither, exactly identical to DD-10776 dither position #1 1783027835161 53.0 The scheduling data was generated by CASM 34.1. CASM was run in Phase II mode. /Users/physsl/Research/00_M82_Echoes/HOPR_Requests/HOPR_02_Apr2026/OP-cache/TEST_PhaseIIAPT_GO17744-v06.xml Sixth orbit, sixth mosaic position (M82-POS6, SE corner): Four of five exposures/dithers executed with identical target, orientation requirement, and POS TARG offsets as the F555W exposures in Visits 61--64 of DD-10776, plus a fifth, more northern, chip-gap-spanning dither postion to provide at least three exposures in every pixel falling in a chip gap. 1774679971000 130.0 (Tic-Visit :proposal-id 17744 :visit-id "06" :proposal-version -1 :trans-version "20260319" :date "02-Jul-2026 17:30:35.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1421120 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17744 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17744 :visit-id "06" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2770 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3092 :pcs-gap 0 ) true 1 1 Default pointing on fixed target with no dither, exactly identical to DD-10776 dither position #1 Small point dither offset from position #1 with POS TARGS +0.124", +0.084", identical to DD-10776 dither position #2 Gap closing dither offset from position one with POS TARGS +0.247", +2.984" , identical to DD-10776 dither position #3 Small point dither offset from position #4 with POS TARGS +0.371", +3.068", identical to DD-10776 dither position #4 New dither position with a positiive/northward, chip-gap-spanning dither, with POS TARGS +0.494", +5.968". This fifth dither (relative to the four dithers in DD-10776) provides for at least three exposed pixels in every chip gap. Using a posittive dither relative to the fixed target pointing in mosaic elements 5 & 6 allows for more total integration time in central portions of the galaxy disk in the overlap zones with mosaic elements 1 & 2. Putting it last in sequence minimizes overhead time lost to the pointing manuevers.