0 Assigned ID: null ----- Attempting Submission 1 (Wed May 23 11:49:51 GMT 2018) ----- Submission failed due to error communicating with the submission server. Please retry in a few minutes. If this error persists please contact the help desk at help@stsci.edu Assigned ID: 2 ----- Attempting Submission 1 (Wed May 23 11:51:26 GMT 2018) ----- MISSING FRINGE FLAT CALIBRATION Sensitive exposures should have an ETC run number provided. Sensitive exposures should have an ETC run number provided. 0 ----- Attempting Submission 1 (Wed Jun 06 11:27:18 GMT 2018) ----- ----- Attempting Submission 2 (Fri Dec 07 18:41:46 GMT 2018) ----- Manual fringe flat in occultation for efficiency and longer exp time for S/N. Star is too faint to require an ETC number. Stellar standards are required for JWST, WFIRST, and LUVOIR flux calibrations and for the science programs of the general astronomical community. In particular, measuring the relative fluxes of redshifted supernovae Ia's is essential for determining the nature of the dark energy that is driving the observed accelerating cosmic expansion. The precision of determining the cosmological constants is tied directly to the precision of the relative flux calibration as a function of wavelength. The CALSPEC archive of HST/STIS spectral energy distributions (SEDs) has become the reference gold-standard database for the best fundamental flux standards that are currently available. This proposal will significantly improve the legacy value of CALSPEC by verifying the utility of the several WD standards that have been established by fitting WD models to WFC3 photometry and will extend the CALSPEC archive to standards fainter by about 3 mag. The limit of STIS dynamic range is around V=16, while fainter standards are required for larger telescopes, eg. LSST and Pan-STARRS. This void is being filled by the A. Saha HST programs 12967, 13711, and 15113, which observes WD stars and models ground-based spectra of their Balmer lines to determine Teff and log g. Then, WD models fitted to WFC3 photometry determine absolute SEDs that include interstellar extinction effects (Narayan et al. 2016). The brightest of the Saha program WDs, SDSS J151421 at Sloan g=15.7, requires only 2 STIS orbits and will produce a new CALSPEC standard that provides an essential, minimal confirmation and an error estimate for the model fitting techniques of the Saha pro- gram. The STIS SED provides a more precise constraint on extinction from the interstellar Dust than is currently possible with the Saha program of WFC3 broadband photometry. This verification is essential for certifying the Saha WDs as precise flux standards that are worthy of inclusion in CALSPEC. Cosmology Stellar Physics 0 false SUPPORTED STAR DA NO This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 1544207930007 /private/var/folders/z_/djm2wnzn3dsckgyfmz_dz3kr0005bh/T/OPVisit110834214523335999.xml The scheduling data was generated by CASM 26.2.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15487 :visit-id "01" :proposal-version -1 :trans-version "20181130" :date "07-Dec-2018 13:38:49.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 395280 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15487 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15487 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2809 :al-overhead-at-end 239 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15487 :visit-id "01" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2839 :al-overhead-at-end 116 :internal-dur-at-end 1165 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3142 :pcs-gap 0 ) true 2 0 Manual fringe flat used instead of default to get higher S/N.