We propose to take an E140H observation of the 0.2" x 0.5" slit illuminated by one calibration lamp, in order to determine the line-spread function (LSF). Almost 50 archival observations will benefit from this LSF, so there will be a immediate return for the scientific community. There will be a direct application for Lyα observations of the interplanetary hydrogen. Moreover any future observation will also benefit of this lamp observation. We will take an E140H observation of the 0.2" x 0.5" slit with HITM2, one of the three hollow cathode Pt/Cr-Ne arc lamps. This lamp exposure will provide a thinner emission line and a better estimate of the LSF for archival or future STIS observations. A previous lamp exposure with HITM2 (OBL601010) used the E140H grating with the 0.2" x 0.09" slit, yielding a maximal count rate lower than 0.07 counts/sec/pixel. With the 0.2" x 0.5", the maximal count rate should be lowert than 0.42 counts/sec/pixel, so well below the bright object limit for the FUV-MAMA (75 counts/sec/pixel). The exposure will be as long as possible. The full orbit, if possible. SOLAR SYSTEM 12 true 0.0 0.0 false false false false AVAILABLE STIS/FUV-MAMA Spectroscopic No No E140H 1234 The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. The lamp will be HITM2 (Tic-Visit :proposal-id 12947 :visit-id "01" :proposal-version -1 :trans-version "20120604" :date "10-Jul-2012 23:19:01.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 0.0 :data-volume 208704 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12947 :visit-id "01" :obset-id "01" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 12947 :visit-id "01" :orbit-number 1 :pcs-time 0 :si-vis-utilization 0 :al-overhead-at-end 0 :internal-dur-at-end 5750 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 0 For the previous exposure with the HITM2 lamp and the 0.2" x 0.09" slit (OBL601010), the global count rate was about 41 counts/sec. So with the 0.2" x 0.5", the global count rate should be about 250 counts/sec. According to the criteria in the instrument handbook (page 235), the buffer time can be taken as half of the exposure time, so we are taking 2500 sec.