README web version of /home/usg/OPS/MTS/readme_xml/readme_77079801

Principal Investigator Email Address

• mjm@astro.ex.ac.uk

Estimated Total Execution Time (hours, including overheads)

• 2.75

General Description

• This is a FORS2 program to monitor the orbital motions of Eps Indi Ba,Bb,
   the nearest known binary brown dwarf system, against a network of background field
   stars. The separation was 0.732 arcsec at PA=137 degrees E of N in August 2003 and
   is presently about 0.9 arcsec, maximum separation. The system also has a very high
   proper motion of 4.7 arcsec/yr. Six epochs of observations are needed in P77, spaced
   roughly by 1 month throughout the period.
  
  A dithered set (10 x 20 secs) of FORS2 I-band images is taken at each epoch: the
   SR collimator is used to get a wide field-of-view, with the 200kHz,1x1,low read-out
   mode to get the best possible spatial resolution at the same time. Additional twilight
   sky flats are therefore needed at each epoch: OBs have been prepared.
  
  The target coordinate is an empty point in the sky, roughly where Eps Indi B will
   be in late 2007, halfway through a five year monitoring campaign. The plan is to
   use the same basic pointing for all observations, in order to ensure that the same
   net of field stars is seen throughout, as Eps Indi B moves over the background at
   4.7 arcsec/yr.

Waiver Requests

• 077.C-0798B.01.WAV:
  Request for 3 week postponement to the Phase 2 submission deadline from February
   09 to March 02 2006
  Requested: January 26 2006
  Granted: January 30 2006
  
  077.C-0798B.02.WAV: 
  Request to allow use of 200kHz,1x1,low mode to get full field of view with SR collimator
   along with best possible spatial resolution.
  Requested: February 27 2006
  Granted: February 28 2006

Critical Observing Condition Constraints

• We have been granted observations with a seeing constraint of 0.6 arcsec
   or better, in order to be able to separate the two sources and obtain accurate relative
   positions. The better the image resolution is, the better the results. All efforts
   taken to taek the data in excellent seeing conditions will be most appreciated.
  
  Clear conditions are required for our relative photometric measurements within the
   field.

Time-Critical Aspects

• To ensure good sampling of the motions of Eps Indi Ba and Bb, we require
   observations roughly evenly spaced throughout P77. This clearly depends on the availability
   of the target, the times when FORS2 is scheduled for service mode observing, and
   weather conditions. Ideally we would like the 6 epochs to be spaced by 1 month each
   in the May-Oct timeframe (the source is unavailable in April), but practically speaking,
   spacings of 0.5-1.5 months would be ok.
  
  Thus we have imposed time constraints in the OBs with each epoch in a 2 month window
   and with 1 month spacings between the epochs.
  
  IMPORTANT: These windows are designed to allow for flexibility and thus they overlap.
   However, in general, it makes no sense to execute the OBs for two epochs on the
   same night or within a few days. Please try and space the epochs sensibly throughout
   P77!

Special Execution Requirements

• The SR mode of FORS2 is to be used with the 200kHz,1x1 read-out mode (a
   waiver has been granted). This is to ensure a wide field-of-view to get a large
   astrometric reference frame and the highest spatial resolution to well separate
   the binary.

Special Calibration Information

• Twilight flats in the I-band are required in the FORS2 SR/200kHz,1x1 read-out
   mode at each epoch when Eps Indi B is observed. The corresponding calibration OBs
   are included. However, it is not possible to know in advance whether the flats will
   be taken at dusk the night before the observations or at dawn following. Also, it
   is not possible to know in advance when each epoch will be observed over the available
   time window. Thus, for each given epoch at which Eps Indi B is observed, the SM
   observer should select an appropriate twilight sky position from the FORS2 list
   and use it instead of the one entered in the OBs.

ToO Information

• N/A

ToO Activators List

• N/A

Is this a Pre-imaging run ?

• false

Pre-imaging Requirements

• N/A

Source(s) of Pre-imaging

• FORS2

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 ?

• N/A

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 prepared your finding charts with tools other than FIMS,
 do they comply with the specifications on the FORS2 Phase 2 web page ?

• YES