README web version of /home/usg/OPS/MTS/readme_xml/readme_60908700

Principal Investigator Email Address

• linz@mpia-hd.mpg.de

Estimated Total Execution Time (hours, including overheads)

• 1

General Description

• We want to do spectroscopy in the K band on a massive young stellar object.
   We concentrate on the Brackett gamma line and the first parts of the CO overtone
   line series around 2.3 micron. Unfortunately, no feasible AO guide star is available
   within 30 arcsec from the source, so these are Non-AO observations. However, the
   target is bright in the K band. So we hope to get decent spectra in terms of SNR
   despite the tight time constraints.
  For the Brackett gamma line observations we want to apply the spectro-astrometry
   technique, and further details regarding the execution requirements can be found
   in the respective section of this README. Since for every position angle change
   of the slit one has to do a new acquisition (at least in p2pp), we had to split
   the observations into four OBs covering the four intended position angles.
  We speculate that at the telescope, it is not really necessary to execute a full
   acquisition procedure for just a PA change of the slit. IF THIS IS THE CASE, WE
   TENTATIVELY ASK TO USE THE SAVED TIME FOR LONGER BRACKETT GAMMA EXPOSURES, EVENLY
   DISTRIUTED OVER THE FOUR SCIENCE OBs. (A DIT time of 60 seconds is still o.k. for
   the Brackett gamma observations in case the weather conditions are not extremely
   good.)
  
  In the 4th OB, we also include two settings for CO observations around 2.3 micron.
   These will be done just with one position angle; these are standard spectroscopy
   observations.

Waiver Requests

• After consulting the USD (USD request number 18818), it was agreed that
   the 1 hour of granted time can be fully spent on the science target. In addition,
   we were asked to submit an extra OB for the telluric standard, and we do so.

Critical Observing Condition Constraints

• none

Time-Critical Aspects

• Please observe the OBs consecutively in the following order:
  1.) SCI_M8EIR-1
  2.) SCI_M8EIR-2
  3.) SCI_M8EIR-3
  4.) SCI_M8EIR-4
  5.) CAL_HR6879

Special Execution Requirements

• We want to apply the spectro-astrometry technique to our target M8E-IR
   in the Brackett gamma line. That means that spectra at several position angles have
   to be taken. The standard approach is to use 4 slit orientations with 90 degrees
   difference, respectively. That means for our case that we start at PA of 140 degrees
   (SCI_M8EIR-1), then the same direction but antiparallel orientation of the slit,
   i.e. 320 degrees (SCI_M8EIR-2). Then we go to a perpendicular orientation of PA
   = 230 degrees (SCI_M8EIR-3), and finally to the orientation antiparallel to that
   one: 50 degrees (SCI_M8EIR-4).
  Taking spectra at antiparallel slit orientations is vital for the success of the
   method. One tries to eliminate instrumental effects by subtracting spectra with
   opposite PAs (320 deg - 140 deg, 230 deg - 50 deg), since instrumental effects will
   remain constant on rotation whereas any real structure in the source will reverse
   its sign. Hence, curvature or misalignment effects in the optical path can be removed.
  In the final OB (SCI_M8EIR-4), we also included measurements that will cover parts
   of the CO overtone emission around 2.3 micron. The standard star OB (CAL_HR6879)
   should be executed after all the science OBs have been taken in a row (see the TIME
   CRITICAL ASPECTS submenu).

Special Calibration Information

• The one calibration OB CAL_HR6879 is the telluric standard star. These
   data will be used to calibrate all the four science OBs. So this calibration OB
   should be executed only once, after the one hour of science observations. More details
   can be found in the "Special Execution Requirements" part of this README.

ToO Information

• N/A

ToO Activators List

• N/A

Do the README file and the instrument comments of the telluric stars
 OBs include the required S/N/pixel of the spectrum of the telluric star, its spectral
 type and allowed spectral range?

• YES

Do any OBs include wavelength or flatfield calibrations?

• NO

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

• N/A

If the slit viewer guide star is different from the target, are the RA
 and DEC offsets accurate to within 0.05 arcsec and do they take into account the
 relative proper motion between the two objects?

• N/A

If you have preferences which OBs should be executed first for objects
 at similar RA, did you make use of the User Priority field in the OBs?

• N/A