sdss_objid

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

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]