This is a slightly altered version of plan submitted yesterday, 10 May. Two types of changes: -- Target acquisition method. (GSC1-ZZZQ instead of standard method). -- Requirements for times of Visit 2 and Visit 3. Yesterday I misunderstood the duration of Cycle 16. ----- KD ----- ----- Attempting Submission 1 (Thu May 10 18:57:39 GMT 2007) ----- ----- Attempting Submission 2 (Fri May 11 20:17:38 GMT 2007) ----- Target acquisition method: See comments in the plan, and separate e-mail to/from Beth Periello. We have queried the analysts about this. Following Eta Carinae's Change of State Eta Carinae is now known to be undergoing some unusually rapid changes on a timescale of several years. They are probably essential for modeling the star's long-term recovery from its Giant Eruption 160 years ago -- the prototype "supernova impostor" event. Since high spatial resolution is needed to isolate the central star, and the present state will probably not recur in the future, it is important to obtain HST data during the next two years. We propose a cost-effective set of ACS observations with three goals: (1) to obtain a continuing record of the star's rapid UV and visual brightening; (2) to lengthen the temporal baseline of ACS images enough to settle an important question concerning ejecta ages; and (3) to extend the record of morphological changes in the inner ejecta past the midpoint of eta Car's 5.5-year cycle.
-- This plan, using WFPC2(PC), is a substitute for earlier ACS plan -- see Cycle 15 program 10844. -- We concentrate on WFPC2 filter F336W because it nearly matches ACS F330W. Primary goal is to monitor the UV brightness of the central object (Eta Car, the star itself). Central object is too bright for the longer-wavelength WFPC2 'M' and 'W' filters, and the 'N' filters are contaminated by emission lines whose brightness cannot be assessed with available instruments. -- We need at least two independent visits per year, with roughly uniform temporal spacing. This plan includes 3 one-orbit visits. We've chosen not to attempt a two-orbit visit because multicolor imaging has much lower priority than sampling the essential UV brightness trend. Main goal is temporal coverage of progressive brightness trend. -- none requested -- (Regarding early scheduling within Cycle 16): Ground-based photometry suggests that a rapid change occurred a few weeks after our last Cy 15 ACS observation. Therefore, it would be prudent to get data as soon as possible now. -- Criteria for visit timing (3 visits): 1. Visit 1 should occur as soon as feasible (see above). 2. Visit 3 should occur near the end of Cycle 16, even if that is delayed. Eta Carinae is expected to have another "spectroscopic event" in January 2009, and if possible we should get data near that time. 3. Vist 2 should be roughly midway between the other two, but there is no need for it to be exactly midway. After the mid-point may be a little better than before. HOT STARS 0 false 0.0 false false false false false false SUPPORTED STAR ETA CARINAE STAR CIRCUMSTELLAR MATTER EJECTA WIND LUMINOUS BLUE VARIABLE IMPORTANT: Acquiring Eta Car is potentially tricky because of the surrounding Carina Nebula. In this region, bright nebulosity tends to hide large areas in ordinary wide-field plates. (VTT, for instance, is murky around Eta Car.) Therefore we fear that the area distribution of GSC2 guide stars contains "holes." Even worse, some official guide stars cannot be trusted because they're perturbed by nebular features seen with inadequate plate scale. -- All our previous acquisitions of this object, in the years 1991--2006, used special catalog ZZZQ, and it didn't cause any failures. The normal type of acquisition would PROBABLY work, but we're not sure. Therefore we specify ZZZQ in this plan. -- F(2600)=1.3+/-0.3 E-11, F(3400)=1.7+/-0.4 E-11, F(6300)=2.4+/-0.60 E-11 HD93308 J2000 10 45 4.0700 -59 41 4.10 J2000 ACS/HRC Imaging No No F220W ACS/HRC Imaging No No F250W ACS/HRC Imaging No No F330W ACS/HRC Imaging No No F550M ACS/HRC Imaging No No F220W ACS/HRC Imaging No No F250W ACS/HRC Imaging No No F330W ACS/HRC Imaging No No F550M ACS/HRC Imaging No No F658N ACS/HRC Imaging No No F220W ACS/HRC Imaging No No F250W ACS/HRC Imaging No No F330W ACS/HRC Imaging No No F550M ACS/HRC Imaging No No F220W ACS/HRC Imaging No No F250W ACS/HRC Imaging No No F330W ACS/HRC Imaging No No F550M ACS/HRC Imaging No No F658N POS-TARG DITHER 0.559017 LINE 0.559017 false false 143.130096 4 26.56505 WFPC2-BOX 1 false /tmp/OPVisit46726.xml Visit 1 should be done as early as feasible, see notes elsewhere in this plan. Target may have changed appreciably since our last Cy 15 HST observations. (Tic-Visit :proposal-id 11291 :visit-id "01" :proposal-version -1 :trans-version "20070325" :date "11-May-2007 15:11:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 448160 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11291 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11291 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2760 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) true 1 0 /tmp/OPVisit8938.xml Gain 15, because very high count rate in central object. Brightest pixel may saturate at one of the dither points, but probably not at all of them. Gain 15, because very high count rate in central object. We use two different exposure times in order to get high dynamic range in surrounding ejecta. Minimal short-wvl observation for comparison with earlier ACS data. Count rate is expected to be high, but not as high as for the other filters. Minimal red observation, for comparison with many pre-2003 WFPC2(PC) F631N data. Very high count rate in central object. /tmp/OPVisit46727.xml Visit 2 should occur roughly midway between Visits 1 and 3, if feasible -- but it doesn't need to be exactly midway. The main requirement is that Visit 2 should not be close to either of the other two. . (Tic-Visit :proposal-id 11291 :visit-id "02" :proposal-version -1 :trans-version "20070325" :date "11-May-2007 15:12:00.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 448160 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11291 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11291 :visit-id "02" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2760 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) true 1 0 /tmp/OPVisit8940.xml Gain 15, because very high count rate in central object. Brightest pixel may saturate at one of the dither points, but probably not at all of them. Gain 15, because very high count rate in central object. We use two different exposure times in order to get high dynamic range in surrounding ejecta. Minimal short-wvl observation for comparison with earlier ACS data. Count rate is expected to be high, but not as high as for the other filters. Minimal red observation, for comparison with many pre-2003 WFPC2(PC) F631N data. Very high count rate in central object. /tmp/OPVisit46728.xml Visit 3 should occur near the end of Cycle 16, if feasible. Eta Carinae is expected to have an important "spectroscopic event" in January 2009, so we're especially interested in the brightness just before that. If the end of Cy 16 is delayed far enough, it may be useful for visit 3 to occur in January 2009, or close to that. -- Anyway, if a further delay in the end of Cy 16 is announced beforehand, then it will be advantageous to postpone Visit 3 accordingly. (Tic-Visit :proposal-id 11291 :visit-id "03" :proposal-version -1 :trans-version "20070325" :date "11-May-2007 15:12:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 448160 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11291 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11291 :visit-id "03" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2760 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) true 1 0 /tmp/OPVisit8937.xml Gain 15, because very high count rate in central object. Brightest pixel may saturate at one of the dither points, but probably not at all of them. Gain 15, because very high count rate in central object. We use two different exposure times in order to get high dynamic range in surrounding ejecta. Minimal short-wvl observation for comparison with earlier ACS data. Count rate is expected to be high, but not as high as for the other filters. Minimal red observation, for comparison with many pre-2003 WFPC2(PC) F631N data. Very high count rate in central object.