README web version of /home/usg/OPS/MTS/readme_xml/readme_82028500

Principal Investigator Email Address

• ledesma@mpia.de

Estimated Total Execution Time (hours, including overheads)

• 1:59:45

General Description

• With the help of an extensive photometric monitoring program in the young
   (1 Myr) Orion Nebular Cluster (ONC, distance 450pc) we derived rotational periods
   of nearly 500 objects, 120 of which are potential brown dwarfs (BD). The faintest
   of these rotational variables  has I=20.7 mag and corresponds to a BD of only 15
   Mjup in ONC if an average Av=1.5 is assumed. This is by far the most extensive and
   complete rotational periods data set in the very low mass (VLM) star and BD regime
   and it will represent the most important reference sample for all future angular
   momentum evolution study in this  mass regime for many years to come. In order to
   exploit the great scientific potential of this sample we propose here medium resolution
   (R =2500) multiobject spectroscopy to derive spectral types, Av values, masses and
   mass accretion rates of these pre-main sequence (PMS) objects.

Waiver Requests

• Waiver submitted July 14 2008 and approved July 14 2008.
  For the pre-imaging we require not only the default (mandatory) R filter but we
   definitely need pre-imaging with the z filter. The reason why an image in R is useless
   is the strong brightness of Halpha emission from the Orion nebula in this band.

Critical Observing Condition Constraints

• No critical observing constrains. Our observations are in principle not
   restricted to a certain lunar phase. However during full moon, one has to make sure
   that the moon is at least 60 degrees away from the target.

Time-Critical Aspects

• No time critical aspects.

Special Execution Requirements

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Special Calibration Information

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ToO Information

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ToO Activators List

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Is this a Pre-imaging run ?

• true

Pre-imaging Requirements

• For the pre-imaging we require not only the default (mandatory) R filter
   but we definitely need pre-imaging with the z filter. The reason why an image in
   R is useless is the strong brightness of Halpha emission from the Orion nebula in
   this band.

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 ?

• YES

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 ?

• N/A

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 specify suitable guide stars for all your OBs using Guidecam
 ?

• YES

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
 ?

• YES