Calibration data for CRIRES are taken for two purposes:

• assess the instrumental status
• calibrate SCIENCE data.

CRIRES calibration data are in general taken during daytime. On request by the user, also night-time calibrations can be obtained as part of the Observing Block which generates the SCIENCE data ("attached calibrations"). Telluric and spectro-photometric standard stars are observed upon request.

The CRIRES data format is described here.

The following calibration data are taken as part of the daily CRIRES calibration plan and/or upon request by the user. Data types are identified by the DPR TYPE keyword in the FITS headers.

frame DPR.CATG DPR.TYPE DPR.TECH purpose N* FITS headers examples DARK CALIB DARK IMAGE detector status, dark current 3 dark.hdr FLAT CALIB FLAT SPECTRUM blaze function, fixed-pattern noise 1 flat.hdr DETLIN (series of darks and flats with increasing DIT) CALIB DARK FLAT LINEARITY,LAMP LINEARITY,LAMP detector non-linearity 17 17   see dark and flat examples ARC LAMP CALIB WAVE,LAMP SPECTRUM wavelength calibration 1 wave_arc.hdr GAS CELL CALIB WAVE,ABSORPTION-CELL SPECTRUM wavelength calibration 1 wave_n2o.hdr STD CALIB STD SPECTRUM,DIRECT,OTHER SPECTRUM,DIRECT,JITTER SPECTRUM,NODDING,OTHER SPECTRUM,NODDING,JITTER telluric features, instrumental efficiency n/a std.hdr

* N: typical number taken per night and setting

Complete overview of calibration files and recipes

Naming scheme

After production and certification, the calibration products are renamed with a more user-friendly scheme which includes type, creation date and relevant setting parameters.

Description of naming scheme

CALIBRATION CASCADE

The processing of CRIRES 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.

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 solution, but that specific solution is chosen which is closest in time.

All products created by DFO Garching follow the calibration cascade. On contrary, Paranal-processed science data never use the up-to-date calibration products but pre-manufactured standard solutions that are possibly several months old.

STATIC CALIBRATION TABLES

The following static calibration tables (the ones not being regularly processed from raw calibration data) are required for CRIRES data processing:

• line tables for ThAr emission lines, N2O absorption lines, and sky lines
• standard star fluxes
• configuration of the physical model.

They come as FITS tables and are part of the Service Mode delivery.

The static tables can be downloaded as gzipped tar file here [19.3 MB, created in May 2007].

 

FILE NAME PRO.CATG DESCRIPTION lines_thar.fits CALPRO_THAR_CATALOG catalog of ThAr lines lines_n2o.fits CALPRO_N2O_CATALOG catalog of N2O lines lines_hitran.fits CALPRO_HITRAN_CATALOG catalog of sky lines (for > 1800nm) lines_oh.fits CALPRO_OH_CATALOG catalog of OH sky lines (for < 1800nm) stdstars.fits CALPRO_STD_PHOTOFLUX table of photometric standard star fluxes model_conf.fits CALPRO_MODEL_CONFIG configuration for physical model

PROBLEMS AND ISSUES

CRIRES pipeline problems are documented on the ServiceMode page.