This page is for dynamic cross identifications of SDSS objects with a
user defined list of object positions, 5-part SDSS object ID (consisting of
run,rerun,camcol,field,obj) for photometric objects,
or 3-part SDSS spectroscopic object ID (consisting of plate, MJD and fiber).
You can even join a photometric object list with matching spectra (SpecObj) if you want
spectroscopic information, or join a spectroscopic object list with matching photometric objects.
Just check the appropriate "JOIN with" box to return the matching objects. You will see the default
query in the query window changing accordingly.
In order to avoid congestion on the server, the upload file is limited to a size of 80KB, and the
radius (for RA/dec search) is limited to 3 arcmin. The crossid search will time out
after 1800 secs, and the output data set can not exceed 500000
Please see the Query Limits page. If this is a
problem, please submit your list in pieces.
Upload list format:
You have the following choices:
You need to either cut/paste the list into the textbox, or upload a text file. Various
extensions (.txt, .dat, .csv, .tbl) are allowed, as long as the MIME type does not get confused.
Binary files are not accepted.
- List of (ra,dec) pairs or list of objIDs (run,rerun,camcol,field,obj)
Always ra comes first, followed by dec. Both ra and dec must be in
degrees. The separator can be any white space or a comma.
The objIDs must be the 5-part SDSS identifiers, i.e. run, rerun,
camcol, field and obj numbers, not the long 64-bit objIDs.
- List of preceding non-data fields followed by (ra,dec) or (run,rerun,camcol,field,obj) data fields
The fields must always be in this order. The preceding columns can be any fields that
you want repeated in the output. The number of preceding columns must be specified in
the second parameter above. The default example shows one preceding column ("name").
Both ra and dec must be in degrees. The separator can be any white space or a comma.
- Same as above, with a single header line
The formats (1) and (2) can also contain a single header line,
containing the column names. The header must use the same separator as the data.
The names ra and dec or run,rerun,camcol,field and
obj are mandatory.
- Lists in the IRSA Gator format
For details see the IRSA website.
If both the paste buffer and file upload are specified, the file upload takes precedence.
Setting up query in the query window:
Add or remove fields that you want returned from the SELECT list, and add more constraints to the WHERE
clause if you desire (preceded with a boolean operator). If your query does not include a p.objID field in
the SELECT for a photometric object list, it will be added for you, because the matching with the upload
list is done based on objID. You may also replace PhotoTag with Galaxy, Star, or any other
photo view or table if you want to restrict the kind of object that is matched. Remember that PhotoTag
will be the fastest usually because it is a thin table (more rows fit in the cache), so unless you need the
fields from larger tables, use PhotoTag (with a mode or type constraint if necessary). Make sure the photo
table/view is aliased as 'p'. Similarly you can replace SpecObjAll with SpecObj as applicable.
Do not modify the #x and #upload parts of the FROM clause otherwise your upload will
If you have a header row with the column names, the #upload temp table created for you on the server will
have the corresponding column names with a "up_" prefix, e.g., up_name, up_ra, etc. You can
then refer to these columns as "u." in your modified query.
Getting FITS files from the SAS
If run, rerun, camcol and field columns are included in the imaging columns list, a button will be included on the
query results page to upload the list of fields to the SAS for FITS file retrieval. If spectra are included and
the SELECT list includes the columns plate, mjd and fiber, a button will also be included on the results page to upload
the spectra list to the SAS to retrieve FITS spectra. The default queries include these columns for your convenience.
The CrossID query is limited to 1800 seconds and 500000 rows.
Please see the Query Limits page.