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