This investigator's institution has no country in the STScI database. The specified Bright Earth Avoidance angle is outside the permitted range. The specified Bright Earth Avoidance angle is outside the permitted range. The specified Bright Earth Avoidance angle is outside the permitted range. The specified Bright Earth Avoidance angle is outside the permitted range. The specified Bright Earth Avoidance angle is outside the permitted range. The specified Bright Earth Avoidance angle is outside the permitted range. The specified Bright Earth Avoidance angle is outside the permitted range. The specified Bright Earth Avoidance angle is outside the permitted range. The specified Bright Earth Avoidance angle is outside the permitted range. 01/08/2019 - ROYLE - Submitting on behalf of the observing team for final epoch visits 03 and 09 -1669624636 ----- Attempting Submission 23 (Tue Jan 08 16:02:35 GMT 2019) ----- in-house processing We propose UV-Visible imaging of the *best* field in JWST's Continuous Viewing Zones where one can conduct a deep and wide extragalactic survey at *arbitrary* cadence and orientation. This 7' radius time-domain field near the North Ecliptic Pole (1) is devoid of sources brighter than m_AB~16 at ~4 micron, (2) has low Galactic foreground extinction, (3) was proven suitable to m_AB~26 mag in deep ground-based images, (4) includes a self-calibrator source for VLA/VLBA radio observations, and allows follow-up with other space- and major ground-based facilities from X-ray through radio. From our proposed HST imaging to m_AB~28 mag (the JWST spectroscopy limit) we will set the table for JWST, with (a) the first two-epoch (37-73 day) baseline for time-domain science (AGN, SNe, proper motions), and (b) identification of ultra-high-z imposters: rest-frame UV-bright objects at z<~6 that would contaminate JWST ultra-high redshift galaxy samples. From extant data and these proposed HST observations we aim to: (1) Establish a baseline UV-Visible detection image at ~0.05" FWHM, and provide a map of transients and objects moving on 37-73 day time scales; (2) Identify galaxies with UV-Visible SEDs with significant non-thermal emission (weak AGN, QSOs), assess the possible escape of LyC photons at 2<z<3, and place limits on that escape and IGM porosity at 3<z<5.6; (3) Study mass assembly and evolution of all significantly resolved UV-bright galaxies at z<~6 on a 'pixel-by-pixel' basis. In order to maximize the scientific return of early-release JWST science, it is critical to image this field in the UV-Visible while HST is still in its prime and before the JWST launch. This program will provide near-contiguous 3-filter UV--visible HST imaging of ithe central ~5' radius portion of the JWST North Ecliptic Pole (NEP) Time-Domain Field (TDF), for which allocated GTO observations will provide both NIRCam imaging and NIRISS slitless spectroscopy at four distinct "spokes". JWST ERS and GO observers will have access to the GTO data, so we anticipate time-domain follow-up as early as JWST Cycle 1, as well as additional areal coverage within this field. The JWST NEP-TDF was defined to be the cleanest >10'x10' area in JWST's northern Continuous Viewing Zone (CVZ), where JWST can conduct a deep extragalactic time-domain survey, with added utility for extreme outer solar system and near-Galactic time-domain science. To maximize (1) overall HST coverage of the JWST NEP TDF, (2) overlap of the UV coverage of WFC3/UVIS F275W and visible coverage of ACS/WFC F435W and F606W, and (3) execute this program as efficiently as possible, we specify seven 4-orbit visits using near-CVZ and CVZ orbits with orientations and POS TARG offsets such that WFC3/UVIS F275W observations at one orientation will largely overlap ACS/WFC F435W and F606W obervations at an alteranate orientation in our "heptagram" pattern. One 4-orbit central pointing with WFC3/UVIS as primary instrument, plus one 4-orbit central pointing with ACS/WFC as primary instrument complete the contiguous HST coverage of the JWST NEP TDF. The orientation of these central pointings is such that their respective coordinated parrallels also overlap, and will overlap NIRCam coverage, which extends to r~7'. This observational design brings our program to the total of 36 primary and 36 coordinated parallel orbits approved in Phase I. Through experimentation in Phase II, we found that the seven "heptagram" visits optimize better when we define the ACS/WFC observations as primary and the WFC3/UVIS observations as coordinated parallels. Availability of HST guide stars for each of the 9 visits forced a change in center position of 90"W and 14"S. Neither adjustment changes the intent or scope of this program. 6 false false false false false false false AVAILABLE UNIDENTIFIED HIGH LATITUDE FIELD INFRARED EMITTER OPTICAL EMITTER ULTRAVIOLET EMITTER The target field is the central ~5' radius portion of the JWST North Ecliptic Pole (NEP) Time-Domain Field (TDF), for which allocated JWST GTO observations will provide both NIRCam imaging and NIRISS slitless spectroscopy. This field was defined to be the cleanest >10'x10' area in JWST's northern Continuous Viewing Zone (CVZ), where JWST will conduct a deep extragalactic time-domain survey, with added utility for extreme outer solar system and near-Galactic time-domain science. The JWST-NEP-TDF (or WTDF) is being developed as a *community field*. This HST program will provide contiguous 3-filter coverage in the UV--visible. The specified target coordinates (17:22:47.896, +65:49:21.54) are offset 90" W and ~14"S from the nominal JWST-NEP-TDF field center (17:23:02.55, +65:49:36.0) in Phase I following a detailed evaluation of suitable HST guide stars in the GSCv2.3. The JWST and Chandra field centers will be shifted to match that of HST. WTDF J2000 1506832828000 69.0 false -1 -1 1512166118000 16.0 false -1 -1 false -1 -1 There are three other potential start times on day 81 that need to be added via BETWEEN. 1521722025000 277.0 false -1 -1 1526209378000 214.0 false -1 -1 1530866500000 162.0 false -1 -1 1535181053000 110.0 false -1 -1 1535095229000 115.0 false -1 -1 false -1 -1