README web version of /home/usg/OPS/MTS/readme_xml/readme_77022601

Principal Investigator Email Address

• boekel@mpia.de

Estimated Total Execution Time (hours, including overheads)

• 2 hours

General Description

• This propsal concerns circumstellar disks around young intermediate mass
   stars.
  It aims to verify of disprove hypothesis about
  1. the spatial structure of such disks,
  2. the dust properties in the disks, especially the spatial distribution of different
   dust species.
  
  Due to the nature of the objects and the technique, it is important to measure in
   a specific
  LST interval (for this sub-run, constraints are not so tight, with a 1h42m and 2h24m
   suitable
  interval for each of the science OBs, respectively). Below there is some
  more information fyi, (after the note on the finding charts), but this is not needed
   for 
  proper execution of the OBs 
  
  A note on the finding charts:
  The science OBs have 'normal' finding charts attached, but additionally contain
   UV plots
  displaying positions in the UV plane corresponding to the best times for the measurement
  ("optimum hour angle"), and the tolerances (uv points at minimum and maximum of
   the hour 
  angle range).
  
  
  Optional reading:
  
  Both concern the *radial* behaviour, i.e. how things change with distance to the
   central star.
  Since visibility data is still very scarce and getting good 2D coverage of the UV
   plane is
  too time-costly, we have to adapt a strategy that circumvents that problem. We have
   chosen
  to measure visibilities at baselines of different length, but approximately the
   same position
  angle on the sky. We measure at 3-4 baselines for each object, in order to sample
   the predicted
  visibility behaviour (see ascii art below, and the proposal for more details). The
   behaviour
  of visibility curve is thus sampled, even if the disk inclination/orientation are
   unknown
  (observing an inclined disk yields qualitatively the same curve as sketched below,
   but
  "expanded" in the baseline direction if one looks along the minor axis of the system.
  
  
  
  1 |_
    | \
    |  \
  V |   \
    |    \_________
    |              \____
    |                   \__
    |  |   |  |  |         \_  __---__
  0 |________________________\/_______\__
    0                   200
         Baseline
  
  A sketch of a predicted visibility curve (see proposal for more details). The
  baselines at which we sample it, are indicated by the | symbols.

Waiver Requests

• none

Critical Observing Condition Constraints

• We are measuring in sci-phot mode. Given the proven performance of MIDI,
  these measurements should be comfortably clear of the performance limit if
  the weather conditions are not too dramatic.

Time-Critical Aspects

• It is important to measure within the indicated LST ranges.

Special Execution Requirements

• The science case is built on having accurate visibilities (within 2 or
   maybe 3 percent).
  This calls for sci-phot mode. We *easily* found and tracked fringes on 2 out of
   the 3
  sources in this programme on UT2-UT3, under *bad* circumstances (+2 arcsec seeing,
   MCAO
  loops opening and closing all the time, big mess). Therefore, it should under "normal"
  (i.e. not exceptionally good, but not too bad either) circumstances not be a problem
  to perform these measurements in sci-phot mode. Due to the nature of the science
   case,
  it is *NOT* helpful to switch to high-sens in case fringes cannot be found. But
   as said,
  the already measured fringes tell us that when fringes can't be found, likely the
   conditions 
  are bad or the system's not functioning as well as it could/should!
  
  Probably best to start with the shortest baselines, and work your way through towards
  the longest!

Special Calibration Information

• hd_146003,  Flux 20.2 Jy @ 10 micron, spectral type M2III
  hd_176411,  Flux 10.8 Jy @ 10 micron, spectral type K1III

ToO Information

• ---(Empty)---

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 ?

• YES

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 ?

• N/A