These observations are extremely time-critical so we would appreciate that this proposal is evaluated as soon as possible. Note also that the information contained is strictly embargoed. -34361159 Assigned ID: 1510 ----- Attempting Submission 1 (Fri Aug 18 02:35:32 GMT 2017) ----- Warnings from bright object tool - due to nearby galaxy. Can we mitigate for this? -1625961781 ----- Attempting Submission 1 (Fri Aug 18 16:38:49 GMT 2017) ----- GRB170817A is the most nearby short GRB ever discovered. We detected an optical counterpart using DECam and propose to obtain a UV spectrum using STIS. 1 orbit UV spectrum of LIGO BNS optical counterpart. Using STIS + G230L for wide wavelength coverage. Stellar Physics 0 SUPPORTED EXT-STAR GAMMA RAY BURSTER NO J2000 J2000 UVW1 ~ 17.7 EXT-STAR GAMMA RAY BURSTER NO J2000 J2000 UVW1 ~ 17.7 STIS/NUV-MAMA Spectroscopic No No G230L 2376 1503073587438 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. 1503455431000 123.10467418397798 (Tic-Visit :proposal-id 15382 :visit-id "01" :proposal-version -1 :trans-version "20170613" :date "18-Aug-2017 12:26:27.0" :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 87408 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15382 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15382 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2846 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3217 :pcs-gap 0 ) false 1 0