I am still nervous about one aspect of this program, the acquisition technique. Unfortunately the region around the Carina Nebula appears to be very bad for GSC2, judging from the VTT. See comments about this in the target list. -- KD -- ----- Submission 1 (Tue May 16 03:05:12 GMT 2006) ----- There are two types of diagnostic message here. Here is my understanding of the situation: -- (1) Targets are listed in GSC1 coordinates for special catalog ZZZQ. APT says "not allowed except for engineering proposals." However, there are reasons not to trust GSC2 for this object, and special catalog ZZZQ has always worked in the past. I am not sure about this, but GSC2 appears bad in the vicinity of NGC3372 for reasons explained in a comment in the target list. I'm certainly willing to try GSC2 instead, but don't want to be blamed if there's an acquisition failure due to GSC2. -- (2) Another warning message concerns an insufficient time between Visits 01 and 02 which are requested to occur together. Normally Visits 01 + 02 (one orbit each) would be considered one visit, but splitting them is the only way I can think of to force a necessary ACS buffer dump at the end fo the first orbit. Therefore the timing requirement for Visits 01 + 02 is intended merely to signal that they belong together (if possible). Thus the warning message is not really substantive. -- KD -- Assigned ID: 152 ----- Submission 1 (Thu Jan 26 22:57:03 GMT 2006) ----- Phase I Proposal 152 (v_final) successfully submitted. ----- Submission 2 (Thu Jan 26 23:17:55 GMT 2006) ----- ----- Submission 2 (Thu Jan 26 23:33:33 GMT 2006) ----- Phase I Proposal 152 (v_final) successfully submitted. ----- Submission 3 (Fri Jan 27 17:11:36 GMT 2006) ----- 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.
We use two visits in Cy 15. --First visit, one orbit: Mainly short ACS/HRC integrations which are 4-pt dithered to improve the sampling, plus some medium-length exposures where dithering is less essential. --Second visit, two orbits, several months after visit 1: Larger series of ACS/HRC images with short, medium, and long exposure times. Again the short exposures have highest priority. --In each case we use filters F550M, F330W, F250W, and F220W. If time allows, we may also include a short exposure with F658N in the second visit. --We expect to repeat nearly the same plan in HST Cycle 16. One goal is to extend an existing temporal baseline (i.e., ACS data in 2002-05) with a roughly uniform sampling interval of six months or so. This implies two approximate goals for scheduling: (1) Visit 1 should occur fairly near the beginning of Cycle 15, say in the first 3 months. First 2 months would be best. (2) Visit 2 should not follow Visit 1 too closely. An interval of 4 to 8 months is OK, about 6 months would be best. --It is OK to interchange Visits 1 and 2, i.e., Visit 2 can precede Visit 1 if some scheduling consideration makes this appropriate. In that case, however, there should still be an interval of several months between the two visits. -- none requested -- (Regarding early scheduling within Cycle 15): We are monitoring progressive changes in Eta Car. The Treasury Program obtained a number of ACS/HRS images from 10/2002 to 11/2005. The gap between 11/2005 and early-Cycle-15 will be more than half a year. To prevent this gap from becoming too long, we prefer to do the first visit as early as possible -- or, anyway, at the earliest convenient opportunity. HOT STARS 0 false 0.0 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 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. -- These problems were foreseen long ago. Special catalog ZZZQ, prepared from different data in 1989, was used to acquire Eta Car dozens of times from 1990 to 2005, and so far as we know it has never failed. ZZZQ is practically in the GSC1 coordinate system, where Eta Car's position is 10h 45m 3.64s, -59d 41' 04.1". (GSC1 and IRCS differ by about 0.08s in RA at this location, corresponding to 0.6".) -- On the other hand, the GSC2 may be OK. Frankly we don't know how to decide this question without careful tests of GSC2, which we don't have enough information to attempt. -- PROBABLY THE SAFEST PROCEDURE IS TO DUPLICATE THE ACQUISITION PARAMETERS USED FOR PREVIOUS ACS OBSERVATIONS IN 2004-2005. They employed special catalog ZZZQ. F(2200)=3.0+/-1.5 E-12 HD93308 J2000 10 45 4.0700 -59 41 4.10 J2000 STAR ETA CARINAE STAR CIRCUMSTELLAR MATTER EJECTA WIND LUMINOUS BLUE VARIABLE IMPORTANT: For acquisition, see comment for target ETA-CAR-A. We should probably use special catalog ZZZQ as explained there. -- Target position ETA-CAR-X is offset about 4 arcsec relative to ETA-CAR-A, in order to include two or three nearby stars for possible astrometric purposes. F(2200)=3.0+/-1.5 E-12 HD93308X 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 0.151 Pattern copied from web page, ACS-HRC-DITHER-BOX "pattern 26" recommended for half-integer offsets. The parameters are slightly different from default values provided by APT; we do not know which set is more accurate. LINE 0.098 false false 63.58 4 20.07 ACS-HRC-DITHER-BOX 1 false POS-TARG DITHER 0.198 LINE false false 3 44.28 ACS-HRC-DITHER-LINE 2 false Visits 01 and 02 (one orbit each) would normally be one visit; we have separated them merely to force an ACS buffer dump after the first orbit visibility period. See comments for Visit 02. --- Our fundamental timing requirements are really as follows: -- (1) The first observation set (either "Visits 01+02" or else Visit 03) should occur as early in Cycle 15 as possible. Reason: We are monitoring Eta Car's behavior and the last observation was in 2005. -- (2) Then, it is highly desirable for the second set of observations to occur about 6 months after the first -- in other words, near the middle of the AFTER 01 timing requirement that we have specified for Visit 3. Reason: To provide a roughly uniform sampling interval for the monitoring. -- (3) In this plan we prefer to obtain Visits 01+02 first because they obtain far more data than 03. However, it would be acceptable to do Visit 03 first if this makes scheduling significantly easier. In that case, Visit 01 would need a new timing requirement "after 03 by 100 to 250 days." (Tic-Visit :proposal-id 10844 :visit-id "01" :proposal-version -1 :trans-version "20060322" :date "15-May-2006 21:31:56.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 460032 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10844 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10844 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2867 :al-overhead-at-end 0 :internal-dur-at-end 219 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) false 1 0 /eadata/kd/HSTcy15ph2/OP-cache/10844eta23-v01.xml GAIN=4 because count rates are high. All exposures except the shortest will have some saturated pixels. --- We have specified POS TARG dX=0, dY=-1.5", in order to move the target somewhat away from the occulting finger. For the longest exposures the occulting finger covers part of the outer nebula, and we wish to minimize this. For consistency, we specify the same POS TARG for all exposures in this orbit. This requirement is NOT essential, however. This long exposure must coincide with buffer readout, so detector is not idle during that time. There is no CR-SPLIT or dither, but a similar exposure will be obtained in the following orbit. Visits 01 and 02 (one orbit each) would normally be one visit, but we have separated them in order to force an ACS buffer dump after the first orbit visibility period. See comments for Visit 01. --- In order to execute Visits 01 and 02 together, we have used timing requirement "02 after 01 by 0.8 to 1.2 orbits". However, this is not absolutely necessary for the science goals. It would be OK for Visits 01 and 02 to be separated by as much as several days, if this makes scheduling much easier. (Tic-Visit :proposal-id 10844 :visit-id "02" :proposal-version -1 :trans-version "20060322" :date "15-May-2006 21:32:28.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 588832 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10844 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10844 :visit-id "02" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2865 :al-overhead-at-end 0 :internal-dur-at-end 360 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) false 1 0 /eadata/kd/HSTcy15ph2/OP-cache/10844eta23-v02.xml POS TARG dY=-1.5" to move target slightly farther from the ACS occulting finger. See comments for Visit 01. This position is offset about 4" relative to the other one. Reason: To include two or three nearby stars for possible astrometric purposes. For observations of ETA-CAR-X we omit the POS TARG used for observations of ETA-CAR-A. This exposure must coincide with a buffer transfer, and it must not end before the transfer is finished. Here we are trying to make use of the buffer-transfer time, so the detector is not idle then. This exposure will be very heavily overexposed/saturated in the central regions. -- There is no CR-SPLIT, but a companion exposure is obtained in the middle of orbit 1. Note the POS TARG for this exposure (-10,-10 pixels in addition to POS TARG used for the other exposures). Visit 03 uses only one orbit, emphasizing short ACS/HRC exposures which are suitable for the central star and bright inner ejecta. --- IMPORTANT: Our timing requirements are really as follows. (1) The first observations should occur early in Cycle 15. (2) Then there must be an interval of 3--8 months before the other visit. It is highly desirable for the interval to be about 6 months. -- Merely for reasons of APT syntax, in this plan we assume that Visits 01 and 02 occur first. It would be OK to interchange Visits 01+02 with Visit 03 if this makes scheduling much easier. See comments for Visit 01. (Tic-Visit :proposal-id 10844 :visit-id "03" :proposal-version -1 :trans-version "20060322" :date "15-May-2006 21:41:31.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 570432 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 10844 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 10844 :visit-id "03" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2865 :al-overhead-at-end 0 :internal-dur-at-end 340 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3222 :pcs-gap 0 ) false 1 0 /tmp/OPVisit13353.xml Companion for next exposure, even though the exposure times are different. See comments for that exposure. This exposure must coincide with the ACS buffer dump, and exposure time must be about 6 minutes in order to extend beyond the buffer dump. For removing bad pixels, we will use the preceding exposure even though their exposure times differ. --- Note: This exposure and the preceding one use slightly different target positions and they have POS TARGs in order to move slightly away from the ACS occulting finger.