README web version of /home/usg/OPS/MTS/readme_xml/readme_75503400

Principal Investigator Email Address

• eberhard.gruen@mpi-hd.mpg.de

Estimated Total Execution Time (hours, including overheads)

• 03:58:30.000

General Description

• The goal of this programme is to perform deep imaging of the dust trail
   of comet 67P/Churyumov-Gerasimenko. A parallel IR observation with Spitzer (to be
   done in 26-29 Aug 05) will allow us to deduce the dust albedo in the trail.
  
  The trail is a faint, extended, line-shaped source with a position angle of 294
   deg ccwise from north. The expected surface brightness is 28 mag/arcsec^2. 
  
  Following rules for blind presets to faint moving targets no finding charts are
   provided. Field identification by an on-line DSS image is sufficient. A quarter-hourly
   ephemeris of the nucleus is attached. 
  
  The "rotator on sky" has been defined such that the detector y-axis will be parallel
   to the trail, to maximise coverage. 
  3 out of 6 OBs ("east") cover the nucleus and surrounding trail, the others ("west")
   are targeted at the north-westly adjacent trail section. I.e. the latter three OBs
   do not cover the nucleus. Despite this, the ephemeris files in all cases give the
   nucleus coordinates, the specific offset for each OB is given in the aquisition
   template. These offsets are defined such that in every OB the trail is at a different
   x-position in the detector, allowing for later superflatfielding.

Waiver Requests

• No Waiver Request was submitted

Critical Observing Condition Constraints

• clear, seeing < 2.0 arcsec, AM < 2., FLI = 0.0

Time-Critical Aspects

• The target is only visible until September 06, 2005. This programme is
   intended as a parallel observation with Spitzer. The Spitzer observation will be
   done in the interval August 26-29, 2005. To minimise uncertainties in the data analysis,
   a time delay as small as possible between the two observations is desirable. In
   principle, however, the VIMOS observation can be done at any (dark) time before
   Spetember 06. It is desirable that all OBs are executed during the same dark time,
   such that they are not spread over four weeks.

Special Execution Requirements

• This is a moving target!
  
  The coordinates given in the target section are example coordinates for August 1,
   2005. Before starting the OB, the SM observer must update the RA&DEC and tracking
   speed in RA&DEC in the respective OB using the ephemerides information. Note:
   the defined offsets will place on purpose (!) the comet nucleus at the eastern edge
   of the FOV in three OBs ("east") and outside the FOV in the other three OBs ("west").
  
  The aquisition must be executed for each OB to put the target at the desired position
   on the detector. This position is different for all OBs on purpose.
  
  A suitable guide star has to be selected by the telescope operator according to
   the pointing defined by coordinates in the ephemeris file and the RA/DEC-offset
   in the aquisition template. If some vignetting is unavoidable, we suggest that in
   OBs named "east", Q2 and Q3 should not be vignetted. In OBs "west", Q1 and Q4 should
   be free of vignetting. 
  
  A quarter-hourly ephemeris of Comet 67P/Churyumov-Gerasimenko considering the nightly
   visibility window for Cerro Paranal is provided (data for twilight conditions and
   with lunar presence are removed). The ephemeris lists:
  - date and hour (UT)             
  - RA&DEC in J2000             to be entered in OB     
  - RA&DEC motion rate (''/s)   to be entered in OB
  - Airmass                     
  - expected nucleus V-mag   
  - Moon distance (deg)
  - Moon illumination (%)   
  
  For the programme it is sufficient to verify the proper telescope pointing via a
   DSS comparison image. Following ESO rules for blind presets to faint moving targets
   no finding charts are provided.

Special Calibration Information

• None

ToO Information

• None

ToO Activators List

• N/A

Is this a Pre-imaging run ?

• false

Pre-imaging Requirements

• N/A

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 ?

• N/A

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 ?

• N/A

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

• YES

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 ?

• YES

Did you specify suitable guide stars for all your OBs using Guidecam
 ?

• N/A

Did you check that the chosen guide stars are suitable for all the offset
 positions and that they do not produce unacceptable vignetting of the field of view
 ?

• N/A