README web version of /home/usg/OPS/MTS/readme_xml/readme_73044001

Principal Investigator Email Address

• haehnelt@ast.cam.ac.uk

Estimated Total Execution Time (hours, including overheads)

• 60hours

General Description

• We aim to measure Lyman-alpha fluorescence at high redshift
  (z=2.7-3.8) from HI clouds illuminated by the ionizing UV background.
  We will do this through extremely deep spectroscopy (60hours),
  repeating the same long-slit FORS2 setup on the same QSO,
  DMSB2139-0405.
  
  General Overview
  ----------------
  
  We have broken the 60hours into 55 x 1hour blocks as requested,
  plus standard star.
  We have 3 types of Observing Block - identical except for
  a 10arcsec offset along the slit.
  These are denoted Pos-A spec ; Pos-B spec ; Pos-C spec
  Please cycle through these in order
  (ABCABCABC...)
  Note: although they are nominally separate 1hour observing
  blocks, if the observations extend to more than one
  continuous block it is NOT NECESSARY to do a reacquisition
  each time: simply skip to the science exposure and
  repeat the pattern of dithers A,B,C between 3000sec
  exposures (i.e. _absolute_ offsets 0,+10arcsec,-10arcsec,
  0,+10arcsec,-10arcsec etc.)
  along the slit, or
  _relative_ offset sequent 0 10 -20 10 10 -20 10 10 -20
                          A  B  C   A  B   C  A  B   C

Waiver Requests

• Approved Waiver Request Summary
  -------------------------------
  
  This is a continuation of the approved programme 173.A-0440, for
  which we have requested (and had approved) spectroscopic twilight
  sky flats in the same configuration as our observations
  (2arcsec long slit, 1400V grism on FORS2)
  Please pick evening/morning blank patch of sky appropriate
  to the month of observation.

Critical Observing Condition Constraints

• This programme can be done in poor (2arcsec) seeing,
  but requires dark time and clear conditions.

Time-Critical Aspects

• None

Special Execution Requirements

• None

Special Calibration Information

• We would like a standard star observed in the same set-up
  (i.e. 2.0arcsec longslit) on the same night as one of
  the QSO spectra. We have suggested Feige110, but you can
  change this to another spectrophotometric standard
  with similar airmass as our target obsrvations on DMSB2139-0405
  
  Please take arcs and flats during the day following
  every night on which this programme is observed.
  
  Please take some twilight sky flats in our spectroscopic
  long-slit set-up when possible.

ToO Information

• None

ToO Activators List

• None

Is this a Pre-imaging run ?

• false

Pre-imaging Requirements

• (The finding chart is a 30min Keck V-band image, of dimension 5x7arcmin,
  QSO should be visible in a 20sec exposure on VLT)

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 ?

• YES

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 have prepared your finding charts with tools other than FIMS,
 do they comply with the specifications on the FORS2 Phase 2 web page ?

• YES