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La Silla Science Operations: NTT

   NTT Spectroscopy Calibration Plan 
(Minimal Version)
Dave Silva & Gautier Mathys
This document describes the minimal necessary calibration plan for NTT
EMMI spectroscopy programs using the BLMD, REMD, and RILD modes.
The following EMMI modes are NOT supported at this time: DIMD, RILD
MOS, and REMD echelle spectroscopy.

Comeron (1997b) provides a complete description of the purpose of each kind of
calibration data.

example, many programs will require wavelength calibration data before
and/or after every science observation.  Specifying this additional
calibration data is the responsibility of the scientist preparing OBs.

General Remarks
(1) All calibration data described here will be taken using the
following "standard CCD configuration":
    Readout speed: normal
    Windowing: none
    Binning: none
    Exposure Time: > 10 secs to minimize shutter timing effects
Since the entire detector is not illuminated in all modes, standard
detector windows may be defined at a later date.

(2) All calibration data described in this document will be acquired,
named, tracked, processed, and archived via standard Data Flow System
procedures and according to standard Data Flow System protocols..  A
set of calibration OBs will be developed jointly by DMD and the NTT

(3) All programs which require "non-standard" calibration data will
have to acquire and process that data independently.  Many programs
WILL require such non-standard calibration data. Non-standard
night-time calibration activity must be accomplished within the time
allocated to each program by the OPC.  The time necessary to complete
Activity which can be accomplished during the daytime will be absorbed
by ESO.

(4) Classical observers will be asked to adhere to this plan, although
they will not be required to adhere to it.

(5) It is assumed that the NTT Team will monitor the following items
on a monthly (or shorter) basis as part of their normal preventive
maintenance activities:
    shutter timing correction
    detector gain
    detector read-noise
    detector linearity
    bad/hot pixel masks
    dark frames
    low count level flatfields

(6) It would clearly take too much time to provide adequate
calibration for all supported EMMI spectroscopy modes (let alone all
imaging and spectroscopy modes) on all nights.  The nightly observing
schedule must take this into account.  Care must be taken to keep the
number of modes and/or setups per night to a mimimum to allow for
adequate calibration.  Some general guidelines for service observing
will be provided in a separate document..
(7) This plan will be in effect as soon as possible and no later than
the beginning of P59/NTT2.  It will be in effect through the end of
P60.  The imposition of a calibration plan for P61 and beyond is
currently at the discretion of the NTT Team.

Required Calibration Data
DEFINITION: "spectroscopic setup" = any unique combination of elements
and parameters including grating, slit number, slit width, blocking
filter, and central wavelength.

Bias Frames:
    what: nine (9) frames per day for each arm
    when: TBD by NTT Team (coordinated with Imaging Calibration Plan)
Dome Flats:
     level: S/N >= 100 per pixel across entire spectral range
     number: three (3) per spectroscopic setup used during previous night
     when: in early morning *after* a night of observations
     who:  NTT daytime operator
     Comment: During most service observing nights, the number of
              setups per night will be constrained to two (2).
Twilight Flats: (slit function map)
     level: S/N >= 100 per pixel across entire spectral range
     number: one (1) for each spectroscopic setup used
     (There is currently no twilight flat template for spectroscopy.
      An operational workaround will be implemented when this plan
      goes into effect.)
(N.B. Note that "internal flats" are available for all of the
supported EMMI spectroscopy modes.  However, the usefulness of such
flats is variable.  See the EMMI manual or contact the NTT Team for
further information.)

Wavelength Calibration:
    level: S/N >= 10 in relevant lines
    number: one (1) per spectroscopic setup
        (1) before a new setup is used for science observations
        (2) after every telescope preset before science observations
        (3) every two hours during long integration series
    lamp: wavelength region and mode dependent (see EMMI manual)

Spectrophotometric Calibration:
    level: S/N >= 10 per pixel across desired spectral range
    number: one (1) per setup
    when: at night while setup in use
    targets: TBD

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