sdss_objid

pydl.pydlutils.sdss.sdss_objid(run, camcol, field, objnum, rerun=301, skyversion=None, firstfield=None)

Convert SDSS photometric identifiers into CAS-style ObjID.

Bits are assigned in ObjID thus:

Bits	Name	Comment
63	empty	unassigned
59-62	skyVersion	resolved sky version (0-15)
48-58	rerun	number of pipeline rerun
32-47	run	run number
29-31	camcol	camera column (1-6)
28	firstField	is this the first field in segment? Usually 0.
16-27	field	field number within run
0-15	object	object number within field

Parameters

run, camcol, field, objnumint or array of int

Run, camcol, field and object number within field. If arrays are passed, all must have the same length.

rerun, skyversion, firstfieldint or array of int, optional

rerun, skyversion and firstfield usually don’t change at all, especially for ObjIDs in DR8 and later. If supplied, make sure the size matches all the other values.

Returns

numpy.ndarray of numpy.int64

The ObjIDs of the objects.

Raises

ValueError

If the sizes of the arrays don’t match or if the array values are out of bounds.

Notes

• The firstField flag is never set in ObjIDs from DR8 and later.

• On 32-bit systems, makes sure to explicitly declare all inputs as 64-bit integers.

Examples

>>> from pydl.pydlutils.sdss import sdss_objid
>>> print(sdss_objid(3704,3,91,146))
[1237661382772195474]