README web version of /home/usg/OPS/MTS/readme_xml/readme_80004000

Principal Investigator Email Address

• norbert@astro.uu.se

Estimated Total Execution Time (hours, including overheads)

• 4.8

General Description

• We want to obtain R=40,000 spectra of the ultra metal-poor giant HE0557-4840
   ([Fe/H] = -4.8). Using dichroic 2 and the B346 and R760 settings, the new spectra
   will cover the UV, including a number of strong OH lines in the region 310-315nm
   as well as the band head of the NH band at 336nm. This will allow us to determine
   the abundances of oxygen and nitrogen of this star, or to improve the current upper
   limits for these abundances in case of a non-detection of the relevant spectral
   features. The N and O abundances are crucial for constraining the origin of the
   abundance pattern of HE0557-4840. The red arm spectra, covering the Ca IR triplet,
   will mainly be used to improve the log g determination by means of the Ca I/Ca II
   ionization equilibrium.
  
  The aim is to reach S/N = 10 per rebinned pixel at 312nm, which would allow us to
   detect individual OH lines if [O/Fe] > +0.9. During the exposures we will use
   1x1 binning, because we are not readout-noise limited and hence the spectra can
   be rebinned later. In order to make co-addition of the individual spectra easier,
   the total exposure time of 4 hours has been evenly distributed over 5 identical
   OBs with an exposure time of 48 minutes each. 
  
  The slit width in both arms shall be 1''. For avoiding slit losses due to atmospheric
   differential refraction, the slit is put to the parallactic angle, and the derotator
   mode is set to "ELEV" in the OBs.
  
  Due to the high extinction in the UV, our target shall not be observed at an airmass
   larger than 1.2.

Waiver Requests

• No Waiver Request was submitted

Critical Observing Condition Constraints

• None

Time-Critical Aspects

• None

Special Execution Requirements

• None

Special Calibration Information

• Not applicable

ToO Information

• Not applicable

ToO Activators List

• Not applicable

Is this a Pre-imaging run ?

• false

Pre-imaging Requirements

• Not applicable

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 specified the S/N ratio at given wavelength in the User Comments
 field of each OB?

• YES

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

If you need secondary guiding, are there suitable objects within 30 arcsec
 from your target ?

• N/A