FITS Keywords

The FITS keywords used by MEGARA are described in full detail elsewhere (document TEC/MEG/146).

In the following sections, we describe the keywords that are used by the pipeline.

Primary header

Type Keyword Example Explanation
L SIMPLE T Standard FITS format
I BITPIX 16 One of -64,-32,8,16,32
I NAXIS 2 # of axes in frame
I NAXIS1 2048 # of pixels per row
I NAXIS2 2048 # of rows
S ORIGIN ‘GTC’ FITS originator
S OBSERVAT ‘ORM’ Observatory
S TELESCOP ‘GTC’ The telescope
S INSTRUME ‘MEGARA’ The instrument
S OBJECT ‘NGC 4594’ Target designation
S OBSERVER ‘OBSERVER’ Who adquired the data
S DATE-OBS ‘2012-09-20T12:00:11.50’ Date of the start of the observation
S DATE ‘2012-09-20T12:14:12.78’ Date the file was written

Required by the pipeline

Type Keyword Example Explanation
R AIRMASS 1.1908 Mean airmass of the observation
R MJD-OBS 72343.34324 Modified JD of the start of the observation
S IMAGETYP ‘FLAT’ Type of the image
S VPH ‘LR-R’ Type of VPH
S OBSTYPE ‘SLITFLAT’ Type of observation
R EXPOSED   Exposure time in seconds
R EXPTIME   Exposure time in seconds (synonim)
R DARKTIME   TBD
S OBSMODE ‘SLITFLAT Identifier of the observing mode

FIBERS extension

The state of the focal plane of MEGARA is stored in a dedicated extension names FIBERS. This extension contains only headers, the data part will be empty.

Type Keyword Example Explanation
I NFIBERS 643 Number of fibers
I NSPAXEL 644 Number of spaxels
I NBUNDLES 92 Number of fiber bundles
S INSMODE LCB Name of active pseudo slit
S CONFID ‘b7d35e7df0274fde..’ Unique identificator of the configuration
I BUNnnn_P 0 Priority of the target in this bundle
S BUNnnn_I ‘unknown ‘ Name of the target
S BUNnnn_T ‘UNASSIGNED’ Type of target (‘STAR’, ‘SKY’, ‘TARGET’, ‘UNASSIGNED’
I FIBmmm_B nnn ID of the bundle
F FIBmmm_D +3.34565 Declination of the spaxel
F FIBmmm_R 12.342223 Right Ascension of the spaxel
F FIBmmm_O 0.0 Position Angle of the Fiber
L FIBmmm_A T Is fiber active?
F FIBmmm_X -0.4646226291303512 X position of the fiber in the focal plane
F FIBmmm_Y 63.63025 Y position of the fiber in the focal plane