TABLE  PhotoObjDR7

This is a unique match between a DR8 photoobj and a DR7 photoobj, and matches are restricted to the same run/camcol/field. The match radius is 1 arcsec, and within this radius preference is given to a photoprimary match over a secondary. If no primary match exists, the nearest secondary match is chosen. If more than one match of a given mode exists, the nearest one is chosen. The table contains the DR8 and DR7 objids and modes, the distance between them, and the DR7 phototag quantities.

name	type	length	unit	ucd	description
dr7objid	bigint	8		ID_MAIN	Unique DR7 identifier composed from [skyVersion,rerun,run,camcol,field,obj].
dr8objid	bigint	8		ID_MAIN	Unique DR8 identifier composed from [skyVersion,rerun,run,camcol,field,obj].
distance	float	8			Distance in arcmin between the DR7 and DR8 positions
modeDR7	tinyint	1		CLASS_OBJECT	DR7 mode, 1: primary, 2: secondary, 3: family object.
modeDR8	tinyint	1		CLASS_OBJECT	DR8 mode, 1: primary, 2: secondary, 3: family object.
skyVersion	tinyint	1		CODE_MISC	0 = OPDB target, 1 = OPDB best
run	smallint	2		OBS_RUN	Run number
rerun	smallint	2		CODE_MISC	Rerun number
camcol	tinyint	1		INST_ID	Camera column
field	smallint	2		ID_FIELD	Field number
obj	smallint	2		ID_NUMBER	The object id within a field. Usually changes between reruns of the same field.
nChild	smallint	2		NUMBER	Number of children if this is a composite object that has been deblended. BRIGHT (in a flags sense) objects also have nchild == 1, the non-BRIGHT sibling.
type	smallint	2		CLASS_OBJECT	Morphological type classification of the object.
probPSF	real	4		STAT_PROBABILITY	Probability that the object is a star. Currently 0 if type == 3 (galaxy), 1 if type == 6 (star).
insideMask	tinyint	1		CODE_MISC	Flag to indicate whether object is inside a mask and why
flags	bigint	8		CODE_MISC	Photo Object Attribute Flags
psfMag_u	real	4	mag	PHOT_SDSS_U	PSF flux
psfMag_g	real	4	mag	PHOT_SDSS_G	PSF flux
psfMag_r	real	4	mag	PHOT_SDSS_R	PSF flux
psfMag_i	real	4	mag	PHOT_SDSS_I	PSF flux
psfMag_z	real	4	mag	PHOT_SDSS_Z	PSF flux
psfMagErr_u	real	4	mag	PHOT_SDSS_U ERROR	PSF flux error
psfMagErr_g	real	4	mag	PHOT_SDSS_G ERROR	PSF flux error
psfMagErr_r	real	4	mag	PHOT_SDSS_R ERROR	PSF flux error
psfMagErr_i	real	4	mag	PHOT_SDSS_I ERROR	PSF flux error
psfMagErr_z	real	4	mag	PHOT_SDSS_Z ERROR	PSF flux error
petroMag_u	real	4	mag	PHOT_SDSS_U	Petrosian flux
petroMag_g	real	4	mag	PHOT_SDSS_G	Petrosian flux
petroMag_r	real	4	mag	PHOT_SDSS_R	Petrosian flux
petroMag_i	real	4	mag	PHOT_SDSS_I	Petrosian flux
petroMag_z	real	4	mag	PHOT_SDSS_Z	Petrosian flux
petroMagErr_u	real	4	mag	PHOT_SDSS_U ERROR	Petrosian flux error
petroMagErr_g	real	4	mag	PHOT_SDSS_G ERROR	Petrosian flux error
petroMagErr_r	real	4	mag	PHOT_SDSS_R ERROR	Petrosian flux error
petroMagErr_i	real	4	mag	PHOT_SDSS_I ERROR	Petrosian flux error
petroMagErr_z	real	4	mag	PHOT_SDSS_Z ERROR	Petrosian flux error
petroR50_r	real	4	arcsec	EXTENSION_RAD	Radius containing 50% of Petrosian flux
petroR90_r	real	4	arcsec	EXTENSION_RAD	Radius containing 90% of Petrosian flux
modelMag_u	real	4	mag	PHOT_SDSS_U FIT_PARAM	better of DeV/Exp magnitude fit
modelMag_g	real	4	mag	PHOT_SDSS_G FIT_PARAM	better of DeV/Exp magnitude fit
modelMag_r	real	4	mag	PHOT_SDSS_R FIT_PARAM	better of DeV/Exp magnitude fit
modelMag_i	real	4	mag	PHOT_SDSS_I FIT_PARAM	better of DeV/Exp magnitude fit
modelMag_z	real	4	mag	PHOT_SDSS_Z FIT_PARAM	better of DeV/Exp magnitude fit
modelMagErr_u	real	4	mag	PHOT_SDSS_U ERROR	better of DeV/Exp magnitude fit error
modelMagErr_g	real	4	mag	PHOT_SDSS_G ERROR	better of DeV/Exp magnitude fit error
modelMagErr_r	real	4	mag	PHOT_SDSS_R ERROR	better of DeV/Exp magnitude fit error
modelMagErr_i	real	4	mag	PHOT_SDSS_I ERROR	better of DeV/Exp magnitude fit error
modelMagErr_z	real	4	mag	PHOT_SDSS_Z ERROR	better of DeV/Exp magnitude fit error
mRrCc_r	real	4		FIT_PARAM	Adaptive ( + )
mRrCcErr_r	real	4		FIT_PARAM ERROR	Error in adaptive ( + )
lnLStar_r	real	4		FIT_GOODNESS	Star ln(likelihood)
lnLExp_r	real	4		FIT_GOODNESS	Exponential disk fit ln(likelihood)
lnLDeV_r	real	4		FIT_GOODNESS	DeVaucouleurs fit ln(likelihood)
status	int	4		CODE_MISC	Status of the object in the survey
ra	float	8	deg	POS_EQ_RA_MAIN	J2000 right ascension (r')
dec	float	8	deg	POS_EQ_DEC_MAIN	J2000 declination (r')
cx	float	8		POS_EQ_CART_X	unit vector for ra+dec
cy	float	8		POS_EQ_CART_Y	unit vector for ra+dec
cz	float	8		POS_EQ_CART_Z	unit vector for ra+dec
primTarget	int	4		CODE_MISC	Bit mask of primary target categories the object was selected in.
secTarget	int	4		CODE_MISC	Bit mask of secondary target categories the object was selected in.
extinction_u	real	4	mag	PHOT_EXTINCTION_GAL	Extinction in each filter
extinction_g	real	4	mag	PHOT_EXTINCTION_GAL	Extinction in each filter
extinction_r	real	4	mag	PHOT_EXTINCTION_GAL	Extinction in each filter
extinction_i	real	4	mag	PHOT_EXTINCTION_GAL	Extinction in each filter
extinction_z	real	4	mag	PHOT_EXTINCTION_GAL	Extinction in each filter
htmID	bigint	8		CODE_HTM	20-deep hierarchical trangular mesh ID of this object
fieldID	bigint	8		ID_FIELD	Link to the field this object is in
SpecObjID	bigint	8		ID_CATALOG	Pointer to the spectrum of object, if exists, else 0
size	real	4			computed: =SQRT(mRrCc_r/2.0)