What are the spatial properties of a point source on the Kepler focal plane?
The focal plane scale of the instrument is about 3.98 arcsec/pixel. Although Kepler is not meant to be an imaging instrument, each detector module has been focused independently. Some changes in focus and image quality are possible during the mission lifetime. According to the Kepler Instrument Manual, the goal is for 95% of the light (“Encircled Energy”) to fall on an area of 7 pixels or less, and the latest information from the project indicates that the actual 95%-circle is 4.2 arcsec (a little more than 1 pixel) . Note that actual image characteristics may change subtlely from quarter to quarter, or even within seasons, because of differential aberration of starlight. The aberration effect causes shifts up to +/-0.25 pixel and can shuffle the distribution of flux among neighboring pixels. In its extraction of flux from the stellar image, the Kepler pipeline processing software should correct for this effect. • Where can I go to find recent status reports on the Kepler satellite? NA
