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Calculating "Distance to Edge" and "Season-onCCD" Values

Calculations for "Distance to Edge" and "Seasons on CCD" values have three slightly different definitions as explained below:

Distance to Edge Values

  • KIC Targets with defined Kepler Magnitudes - Distances for this group are defined by the Kepler project as the shortest distance from an edge of the CCD to a pixel in the photometric aperture for a given season. Values of 0 or greater are observable.

  • KIC targets with undefined Kepler Magnitudes - Distances were calculated by MAST staff and represent the distance in pixels from the nearest edge of the CCD to the target (i.e., not to the photometric aperture) for a given season. A value greater than 0 would indicate a target is on the detector, but the required aperture size may prevent it from being observed (e.g., for an extended source).

  • Non-KIC targets - Distances are defined as the closest possible distance from the target to the edge (for a given season) with a maximum absolute uncertainty of 22 pixels (i.e., the target could be up to 22 pixels farther from, but not closer to, the edge).

Number of Seasons on CCD

  • For targets with a defined Kepler magnitude (about 4.4 million targets), this represents the number of seasons in which a project-defined distance is 0 or greater. To see non-observable KIC targets, set the "Seasons on CCD" form element to "unspecified".

  • For those KIC targets with unknown Kepler magnitudes (roughly 120,000 targets), this represents the number of seasons that MAST-derived distances (see above) are greater than zero. As above, to see non-observable KIC targets, set the "Seasons on CCD" form element to "unspecified".

  • For non-KIC targets (a total of roughly 7.8 million targets) , the number of seasons with MAST-derived distances greater than or equal to 4. Non-KIC targets must have at least one season on the detector to be included in the database table so values will range from 1 to 4. Note because of the 22-pixel uncertainty, some targets considered off the detector in a given season may actually appear on the detector.