GIRAFFE calibration data are mostly taken as daytime calibrations. Flux standard stars and nasmyth screen flats are taken, as part of the calibration plan, for Argus data.
On request by the user, also nighttime calibrations can be obtained as
part of the Observing Block which generates the SCIENCE data ("attached
calibrations"). Furthermore simultaneous arclamp calibration is available,
upon request, by feeding some fibres with light from the simultaneous
calibration unit (SCIENCE data taken in SimCal mode).
OF RAW CALIBRATION DATA
Find information about the GIRAFFE data format,
spectral format and the detector here.
The following calibration data are taken as part
of the daily GIRAFFE calibration plan. The data types are identified by
the DPR TYPE keyword in the FITS headers.
detector status, bias level
dark current (old and new CCD); CCD glow (old CCD only)
(robotic, taken with the calibration lamp on the robot arm;
this is the regular flat)
MOS (for Medusa) or IFU (for IFU and Argus)
signal localization and extraction; fix-pattern
(taken with the nasmyth screen illuminated; this is the 'attached'
flat taken during the night, useful for Argus mode because of
The ARC-LAMP and FLAT frames split into five fibre system (MEDUSA1/2;
IFU1/2; Argus). They also split into two different gratings (HR and LR)
with a set of standard wavelengths (which are listed here).
BIAS frames are taken in unbinned (1x1) mode, normal or low
gain (fast read mode).
The flux STD data are regularly taken for the Argus and IFU settings.
In addition, DARK frames are taken about monthly, to monitor the dark
A series of about 40 IMAGE FLATs is also taken roughly once per
month, to monitor the status of the detector. They come in pairs with exposure
times increasing from 0 to about 280 sec (saturation). Both types of data are not
required for science reduction.
* used for processing of science files between 2007-10 (before that
date the pipeline did not correct for dark structure) and 2008-03 (after that date,
with the new CCD, there was no need for correction).
** for STD_ARG data ony; for STD_IFU data, no instrument response is produced.
After production and certification, the calibration products are renamed
with a user-friendly scheme which includes type, creation date and relevant setting
The processing of GIRAFFE calibration frames requires a cascaded scheme
where the mutual dependencies of products and raw frames are respected.
The proper sequence of all these production steps is called the calibration
cascade. It is described here.
Within that cascade, all products are checked with respect to their quality
and their relationship in time. This means e.g. that a dispersion solution
is not only generated using an arbitrary quality-checked localization
solution, but that specific solution is chosen which is closest in time.
All products created by QC Garching follow the calibration cascade.
On contrary, Paranal-processed science data never use the up-to-date calibration
products but standard solutions manufactured by QC Garching and possibly several
The following static calibration tables (the ones not being regularly
processed from raw calibration data) are required for GIRAFFE data processing:
the emission line table
the grating tables (one for each grating: HR = high-resolution and
LR = low-resolution)
the slit geometry tables (one for each setup). They provide the fine-tuning
of the dispersion solution, after the physical model has been applied.
They come as FITS tables (extension fits). They are part of the data
packages for GIRAFFE data, and they are also delivered through the calSelector archive