README web version of /home/usg/OPS/MTS/readme_xml/readme_75042501

Principal Investigator Email Address

• pwoudt@circinus.ast.uct.ac.za

Estimated Total Execution Time (hours, including overheads)

• 0.75

General Description

• The aim of these observations is to image the nova shell of the unique
   helium nova V445 Puppis at the highest possible resolution in order to determine
   the distance to this object via its expansion parallax. We expect a maximum radius
   of the nova shell of ~2.5" in 2005 Sept (if the nova is at a distance of 700 pc),
   ie. ~90 pixels
  with the S27 objective. A jitter box of 12" should be sufficiently wide. The total
   integrated magnitude of V445 Pup in 2005 Jan is Ks=13.0 mag, but note that the object
   is extended (it has an expanding asymmetric nova shell). A lower limit for DIT of
   15 s was chosen to avoid saturation if V445 Pup was observed under excellent seeing
   conditions (<0.4") and if all the light is due to the central point source in
   the nova. This is a conservative lower limit as the central point source is subjected
   to heavy extinction by the shell.
  
  The brightest star in the 120"x120" field of view around V445 Pup in the V-band
   (see the attached V-band finding chart) is GSC2S1011002475 at V=10.4 mag (K=10.0
   mag). The brightest star in the K-band is GSC2S101100238439 at K=9.9 mag.
  
  We do require a PSF OB (see special calibration information for details).

Waiver Requests

• No Waiver Request was submitted

Critical Observing Condition Constraints

• In the NAOS PS tool I have specified the worst possible conditions (airmass
   1.4, seeing 0.6) under which this observation is possible. This will give a SR of
   12.5% on target (and 22.5% on the reference star). Given the relative faintness
   of the AO reference star (V=15.5 mag), the AO performance will improve considerably
   with good seeing conditions. The preferred conditions (airmass 1.2, seeing 0.4)
   will result in a SR of 26.3% on target (and 30.6% on the reference star), a very
   big improvement over the (worst possible) correction specified in the AO config
   file.
  
  To summarise: this observation will benefit enormously from excellent seeing conditions
   (seeing < 0.4") but the programme is still feasible for seeing conditions better
   than 0.6"
  
  Thin cirrus is not a problem.

Time-Critical Aspects

• During P75, V445 Puppis is visible only in April/May and September. This
   OB (075.D-0425(B)) is scheduled for September, whereas the first identical exposure
   (075.D-0425(A)) is schedule for April 2005. We would prefer run 075.D-0425(B) to
   be scheduled in September, so to keep the airmass to a minimum (< 1.4) and provide
   the longest
  baseline between 075.D-0425(A) and 075.D-0425(B)

Special Execution Requirements

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Special Calibration Information

• We require a PSF OB (specified in the PSF_V445 Puppis NACO 2 OB) for which
   we have chosen GSC2S101100238599 as the AO reference star (V=15.4 mag, compared
   to V=15.5 mag for the AO reference star for V445 Pup). The chosen PSF star is 25.5"
   away from the PSF AO reference star (compared to 23.9" for V445 Pup and its AO reference
   star) and is GSC2S101100238567. Both the PSF star and the AO reference for this
   star are indicated on the finding chart of V445 Pup. The nova shell of V445 Puppis
   will most likely have fine structure; in order to retrieve this fine structure and
   to remove the central point source, a reasonably good PSF is needed for image deconvolution.
  
  The DITs and NDITs for the PSF OB are smaller (2s x 10) than the DITs and NDITs
   for the prime target (15s x 11). We do not require equal exposure times of prime
   target and PSF. V445 Pup is an extended source and large DIT*NDIT*NEXPO is needed
   to get S/N in the outer regions of the shell; the PSF on the other hand is fairly
   bright (K=12.2 mag). The total brightness of the target V445 Pup (even though it
   is extended) is K=13.0 mag.

ToO Information

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ToO Activators List

• ---(Empty)---

Is this a Pre-imaging run ?

• false

Pre-imaging Requirements

• ---(Empty)---

Source(s) of Pre-imaging

• ---(Empty)---

Pre-imaging sources not listed above

• ---(Empty)---

Do all your OBs comply with the instrument-specific requirements listed
 on the instrument-specific Phase 2 web page ?

• YES

If this is a pre-imaging run, did you select PRE-IMAGING for the Observing
 Category for each Observing Template ?

• N/A

Do all your finding charts comply with both the general and instrument-specific
 Phase 2 Web Pages ?

• YES

If you submitted OBs for standard stars, did you specify the magnitude
 and spectral type of all standard stars in the OBs ?

• N/A

Have you included OBs for any calibrations that you need but which are
 not part of the Calibration Plan ?

• YES

If you are observing Moving Targets, have you attached suitable ephemeris
 files to your OBs?

• N/A

If you have preferences which OBs should be executed first, did you make
 use of the User Priority field in the OBs ?

• YES

If this is a run that requires coordinated observations with other facilities,
 did you give proper instructions in the Time-Critical Aspects Section ?

• N/A

If you have PSF reference star OBs, do the names of those OBs begin with
 PSF_ ?

• YES

If there are Finding Charts attached to your OBs, is the field-of-view
 of at least one of these charts 2' x 2' (with clearly labelled field orientation)
 ?

• YES

Have you clearly marked and labelled your wavefront reference objects
 R1, R2, R3, ... (as specified in the NAOS Preparation Software) on your Finding
 Charts ?

• YES

Have you specified the magnitude of the brightest object in the field-of-view
 for each OB ?

• YES

Are there objects in any of your fields (including standard stars) which
 are brighter than the limits specified in the User Manual and on NACO web Pages
 ?

• NO

If the previous answer is yes, have you given a list of OBs and a justification
 for the brightness limit violation in the general description field ?

• N/A