README web version of /home/usg/OPS/MTS/readme_xml/readme_82027501

Principal Investigator Email Address

• tratzka@aip.de

Estimated Total Execution Time (hours, including overheads)

• 5.0

General Description

• These are MIDI observations of the triple system T Tau. This source consists
   of the northern component T Tau N (bright in the visual) and the southern component
   T Tau S. The separation between T Tau N and T Tau S is 0.7 arcsec. Therefore, these
   two sources can be distinguished in the acquisition images (see finding chart 'TTau_MIDI.jpg';
   however, the flux ratio of the components in the N-band has changed and nowadays
   T Tau S is probably brighter in the thermal infrared). T Tau S itself is formed
   by two stars separated by 0.1 arcsec, that are both highly extincted and can only
   be seen in the near-infrared and at longer wavelengths. Since T Tau N is thus the
   only star of the system visible in the visual wavelength regime, it has to serve
   as Coude guide star during all observations. 
  
  The aim of the observations is to derive individual measurements of the northern
   and the southern component with the prism and the grism:
  
  'TTauN_prism', 'TTauN_grism', 'TTauS_prism', 'TTauS_grism'.
  
  We suggest to execute the observations of the northern and the southern source consecutively,
   since this strategy will help to identify the sources. It will also be helpful to
   reduce the technical overheads. After observing T Tau N (Coude guide star), a small
   offset to acquire/center T Tau S instead of loading a new OB might be sufficient.
   A change of the dispersive element instead of loading a new OB ('*_prism' <->
   '*_grism") might also be preferable.
  
  A fifth OB 'TTauN_field' has been created to observe the whole system in the field
   mode. To derive fringes from all three stars long scans are required.

Waiver Requests

• A 'Change Request' to use the baseline UT2-UT4 instead of the proposed
   baseline UT1-UT3 has been approved on July 23, 2008.

Critical Observing Condition Constraints

• none

Time-Critical Aspects

• none

Special Execution Requirements

• none

Special Calibration Information

• The proposed calibrator HD 37160 is not inlcuded in the 'CalVin'-database.
   The source for the diameter estimate of this star is the 'MIDI calibrator list'
   (B. Stecklum et al.).
  
  HD37160:
  Position =  5 36 54.39 9 17 26.4
  Diameter =  2.02 +- 0.02 marcsec
  Spectral Type: K0IIIb
  Vmag = 4.09 mag
  Hmag = 1.77 mag
  N (Iras) = 6.47 Jy
  Simbad Remark: High proper-motion Star
  Spectrophotometric Star

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

• ---(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 ?

• 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

Did you indicate for each science star OB the corresponding calibrator
 star OB (and vice versa) in the 'Instrument Comments' field ?

• YES

Did you check that your chosen calibrator is bright enough for the instrument
 mode used ?

• YES

If you use calibrator stars which are not in the CalVin database, did
 you specify their characteristics in the README file and in the OBs ?

• YES

Did you verify that your coordinates are as accurate as possible (2Mass
 coordinates recommended) and that they include proper motions if available ?

• YES

Did you specify the LST range of the calibrators such that they cover
 the range from 30 min before the start of the LST range of the science target to
 30 min after the end of the LST range of the science target ?

• YES