The number of orbits used does not match the number allocated VISIBILITY OVERRUN Visit 1 has already been scheduled, but we found a problem. The filter was wrongly specified as F606W in two of the exposures, which I changed to F555W. We also found that we get more exposures if we replace 170 sec with 200sec since some of the overheads are hidden! So we replaced the exposure times, which allowed us one more exposure. We will greatly appreciate if visit 3 can be executed instead of Visit 1, at this late stage! The exp times in visit 2 are ancreased to 200sec. -612362738 ----- Attempting Submission 2 (Tue Mar 18 18:31:37 GMT 2014) ----- HST Phase II Proposal 13466 (13466.apt) successfully submitted. ----- Attempting Submission 3 (Tue Mar 18 18:46:48 GMT 2014) ----- ----- Attempting Submission 4 (Tue Mar 18 20:44:53 GMT 2014) ----- HST Phase II Proposal 13466 (13466.apt) successfully submitted. ----- Attempting Submission 5 (Wed Mar 19 15:36:12 GMT 2014) ----- HST Phase II Proposal 13466 (13466.apt) successfully submitted. ----- Attempting Submission 6 (Wed Mar 19 18:31:35 GMT 2014) ----- ----- Attempting Submission 7 (Mon Mar 24 17:28:21 GMT 2014) ----- can visit 1 be replaced with visit 3 please? Thanks. Determining the Mass of Proxima Centauri through Astrometric Microlensing We propose to determine the mass of our nearest neighbor, Proxima Centauri, using the novel technique of astrometric microlensing. Proxima is a dM6e star, with an estimated mass of about 0.12 Msun, lying at a distance of 1.3 pc and having a large proper motion of 3.8 arcsec/yr. In a reprise of the famous 1919 solar eclipse that verified general relativity, Proxima will pass in front of a pair of 18th-magnitude background stars in 2015, affording us two independent opportunities to measure the relativistic deflection. The first passage will occur in May 2015 (impact parameter 1.5 arcsec), and the second in June 2015 (impact parameter 1.4 arcsec). As Proxima passes in front, it will cause a relativistic deflection of the background stars' images by ~0.5 milliarcsec, an amount readily detectable with HST/WFC3. The gravitational deflection angle depends only upon the distances and relative positions of the stars, and the mass of the lens (Proxima). Since the distance to Proxima is well known from accurate parallax measurements, and the relative stellar positions can be determined precisely before the event, the astrometric measurement offers a unique and direct method to measure the mass of a single, isolated star. We anticipate better than 10% accuracy for the mass determination. The mass of Proxima is of special interest because it is the nearest M dwarf, representing the most common type of star in the Galaxy, for which the mass-luminosity relation is still uncertain at present. The first epoch observations will be taken in a few different filters (F475W, F555W, F606W, F814W) to better characterize the spectral type of the source. Subsequent observations will be taken mainly in 2 filters (F606W and F814W). We will obtain one short (0.5 sec) exposure to get an unsaturated image of Proxima, in order to register its position. The other exposures will be of 90 to 200 sec durations, so that the source stars will have a S/N & 300 in each exposure. We can obtain about 10 such exposures in each orbit, at 2 dither positions, which would be adequate to achieve the astrometric accuracy required for the project. COOL STARS 12 false false 0.0 0.0 false false false AVAILABLE STAR K V-IV This object was updated to the SOURCE that Proxima-Cen is going to lens. At present, the source and proxima-cen are separated by about 10.5 arcsec, and this separation will slowly decrease to 1.5 arcsec in 2015. J2000 J2000 WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F475W The scheduling data was generated by CASM 22.0. CASM was run in Phase II mode. /private/var/folders/xx/kgq1b0qs5jj32f6tg4vg0m5r00067j/T/OPVisit9095137214307377314.xml 59 1396354130000 326.12 (Tic-Visit :proposal-id 13466 :visit-id "01" :proposal-version -1 :trans-version "20131031" :date "24-Mar-2014 13:05:35.0" :trans-errors '(:WARNINGS 1 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 703888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13466 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13466 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3218 :al-overhead-at-end 173 :internal-dur-at-end 190 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3540.0 :pcs-gap 0 ) true 1 1 /private/var/folders/xx/kgq1b0qs5jj32f6tg4vg0m5r00067j/T/OPVisit7630090047629495971.xml 59 (Tic-Visit :proposal-id 13466 :visit-id "03" :proposal-version -1 :trans-version "20131031" :date "24-Mar-2014 13:14:24.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 774272 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13466 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13466 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3066 :al-overhead-at-end 171 :internal-dur-at-end 652 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3540.0 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 22.0. CASM was run in Phase II mode. /private/var/folders/xx/kgq1b0qs5jj32f6tg4vg0m5r00067j/T/OPVisit7422056944537740088.xml 51.3 (Tic-Visit :proposal-id 13466 :visit-id "02" :proposal-version -1 :trans-version "20131031" :date "24-Mar-2014 13:11:02.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 703888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13466 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13466 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2684 :al-overhead-at-end 174 :internal-dur-at-end 575 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3078.0 :pcs-gap 0 ) true 1 0