Other photometric observations (detections)

Due to overlaps in imaging stripes, the SDSS sometimes observes the same object more than once. In such cases, we select one observation as PRIMARY (mode=1). Each astronomical object is assigned a thingID, and each time that "thing" is observed (detected in SDSS imaging), it assigned a separate objID.

Information about each astronomical "thing" is stored in the thingIndex table; thingIndex is a thin coupling table designed only to connect repeat observations. Information about each individual observation (detection) is in the photoObjAll table. (Note that photoObj contains only the primary [mode=1] and secondary [mode=2] observations of each "thing.") The detectionIndex table connects each objID to the thingID it corresponds with.

This detected object and its associated "Thing" (Primary observation)

IAU name objid thingid mode description
SDSS J003447.40-210608.2 1237673017303367759 1707150 PRIMARY

Other Observations of this "Thing"

objid thingid mode mode description
1237673017303367759 1707150 1 PRIMARY
1237667222861447277 1707150 2 SECONDARY