COLLECT: What collection this plate is from, and where you could find it again. 

EPOCH: The epoch of the plate.

INSTRUM: The instrument on which the data were recorded.

SCANNER: The model of the digitizer that was used.

SCANRES: The dpi of the digitized file.
					
SERIES: The series identifier of the plate.

SITE: The name of the observatory at which the negative was taken.

SITE-LAT: The latitude at which the negative was taken.							

SITE-LON: The longitude at which the negative was taken.						
							
TELESCOP: The name of the telescope.

TYPE: The type of plate, ie. spectrum, survey, objective prism, etc.

PLATENUM: The number given to the plate by the observing astronomer. Obtained from the logbooks, envelope, and plate surface.

DATE-LOG: The date of the observation given in the logbook.

DATE-MJD: The date of observation given in the logbook, converted to MJD.

EXP-LOG: The time of exposure, written in the logbook.

EXP-PLA: The time of exposure, written on the plate.

DATE-SCN: The date on which plate was digitizated.

SCAN-OP: The name of the person who created the digitized file.

EMULSION: The emulsion on the plate.

SITE-ALT: The altitude of the observing location.

HA: The hour angle of the observation in degrees, arcminutes, and arcseconds (derived).

AIRMASS: The airmass of the observation (derived).

SCANID: The type of scan of the plate/the second half of plate identifiers. Generally incudes dimension of scan and/or color.

OBSERVER: The name of the observing astronomer.

PUBLICAT: List of places in which the image of this plate was published.

REMARKS: Any remarks the astronomer made about the spectrum or plate. 		

RA-PLATE: The notation of RA on the plate, usually given in hms.							

DEC-PLATE: The notation of declination on the plate, usually given in degrees, arcminutes, and arcseconds.

RA-ENV: The notation of RA on the envelope, usually given in hms.

DEC-ENV: The notation of declination on the envelope, usually given in degrees, arcminutes, and arcseconds.

RA-LOG: The notation of RA in the logbook, usually given in hms.

DEC-LOG: The notation of declination in the logbook, usually given in degrees, arcminutes, and arcseconds.

PLATESZ: The size of plate, given by a lettering system defined elsewhere in the book.

OBJ-LOG: The object of interest, noted in the logbook.

OBJ-ENV: The object of interest, noted on the envelope.

OBJ-PLATE: The object of interest, noted on the plate surface.

RA-FITS-DEG: The RA of the central point on the plate according to Astrometry.net, given in degrees. Same as CRVAL1. 

DEC-FITS-DEG: The declination of the central point on the plate according to Astrometry.net, given in dms. Same as CRVAL2.

SCANHT: The y-axis length of the scan in degrees.

SCANWD: The x-axis length of the scan in degrees.

SCALE-SCN: The number of arcseconds per pixel on the FITS scan.

SCAN-ORI: The orientation of "up" on the scan.