FITS Keywords

Category B	Version 3.0.1

Description

This list shows the keyword that process-fits reads, the SPC variable it sets and a description explaining the setting.

FITS Keyword	Levels	SPC Variable	Description
BITPIX	0/1	BITPIX	This sets the flag in SPC for how many bits to treat the data. Everything is eventually converted into unsigned integer. For ORex, the level 0 data is 16. The camera is a 14-bit imager, but the SPOC will pad the leading bits to 0 to make it a simple unsigned 16-bit integer. IF a LUT (look-up-table) is used, the SPOC will convert the 8-bit LUT into the standard 16-bit integers. For level 1, it is set to -32, which is 32-bit signed.
DATE_OBS	0/1	UTC0	The UTC time of the observation. This is converted within SPC via SPICE into ET, setting both ET0 and ET.
EXPTIME	0/1	EXP	The duration of the exposure. It is used to calculate the midpoint of the exposure. This is _ used for OREx.
SCLK_STR	0/1	CLK0 and CKLUSE	This is the spacecraft clock. If this value is set in the FITS headers, it is the primary time used to calculate the midpoint of the exposure.
NAXIS1	0/1	NPX	Number of pixels wide (the x value)
NAXIS2	0/1	NLN	Number of pixels tall (the y value)
CAMERAID	0/1	CAM	Which camera is being used. Values are 0-Map, 1-Sam, 2-Poly
MTR_POS	0/1	FLT	Defines the position of the PolyCam motor, which is used to calculate its focal position. For MapCam and SamCam, it provides the position of the filter wheel in degrees.
LUT	0	LUT	If LUT is defined, this tells what LUT was used on the spacecraft. No processing is done via SPC because the SPOC has already done it. This variable isn't used
MCFWHTMP	0/1	NTX (1,1)	MapCam temperature. The final algorithm has not been decided yet. However, the weighting of each temperature can be adjusted in the file DN2TEMP.TXT. This assumes a linear mixing of the four camera temperatures. Level 0 is in DN. Level 1 is in degrees C
MCFWMTMP	0/1	NTX (1,2)	see above
MCLENTMP	0/1	NTX (1,3)	see above
MCROETMP	0/1	NTX (1,4)	see above
SCFWHTMP	0/1	NTX (2,1)	SamCam temperature. The final algorithm has not been decided yet. However, the weighting of each temperature can be adjusted in the file DN2TEMP.TXT. This assumes a linear mixing of the four camera temperatures. Level 0 is in DN. Level 1 is in degrees C
SCFWMTMP	0/1	NTX (2,2)	see above
SCLENTMP	0/1	NTX (2,3)	see above
SCROETMP	0/1	NTX (2,4)	see above
PCFWHTMP	0/1	NTX (3,1)	PolyCam temperature. The final algorithm has not been decided yet. However, the weighting of each temperature can be adjusted in the file DN2TEMP.TXT. This assumes a linear mixing of the four camera temperatures. Level 0 is in DN. Level 1 is in degrees C
PCFWMTMP	0/1	NTX (3,2)	see above
PCLENTMP	0/1	NTX (3,3)	see above
PCROETMP	0/1	NTX (3,4)	see above
NCCHTEMP	0	NTX (4,0) and NTX (4,1)	NavCam temperature.
TCCHTEMP	0	NTX (5,0) and NTX (5,1)	TAGCam temperature
SC_QA	0/1	QT(0)	Quadterians. OREx will write the spacecraft pointing information, as of when the image was taken, into the FITS header. process_fits will output them in the file quaternions.txt in the format PICNM, QT(I), I=0,3
SC_QX	0/1	QT(1)	see above
SC_QY	0/1	QT(2)	see above
SC_QZ	0/1	QT(3)	see above
BZERO	0	DDN and SIGNED	FORTRAN reads all integers as signed. Because the data is unsigned, then the DN values less than zero are converted into high-bit values.
INSTRUME	0/1	INAME and NC	Level 0 has OCAMS, so NC is set via CAMERAID-1. This is the name of the instrument in human-readable form. It sets the variable NC as follows:

INSTRUME

NC

Comment

MAP

N/A Because INSTRUME will be OCAMS

SAM

N/A Because INSTRUME will be OCAMS

POL

N/A Because INSTRUME will be OCAMS

NCM

4

NFT

5

OCAMS

CAMERAID+1

/!\ The order of this is important because the camera number is the reference that SPC uses for camera ID within the configuration files make_sumfiles.txt, DN2TEMP, and FLATFIELD.TXT.

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