An issue has been discovered with the fundamental pixel calibration Kepler and K2 short cadence data.
The problem has been traced to an accounting error for the short-cadence collateral smear data. Under some conditions, these data are passed incorrectly between the spacecraft and the ground, causing smear values to be assigned to the wrong columns within a target’s aperture. In these cases, the pipeline's pixel-level calibration routine applies an erroneous smear correction.
The issue has been present since launch and affects both the target pixel files and the light curves of approximately half of all short-cadence targets in all releases to date, i.e. Kepler Data Releases 1-24 and K2 Data Releases for Campaigns 0-5.
Details on the problem can be found on the following page and in the attached document:
http://keplerscience.arc.nasa.gov/problem-with-kepler-and-k2-short-cadence-pixel-calibration.html
On this page you can also find lists of all the stars that are affected.
With the errors found in the latest data release 24 short cadence data, we have implemented filters that will per-default disregard these data in the searches you perform on the KASOC website, and in the data bundles.
However, this has the unfortunate side-affect of re-introducing the timing error, that was otherwise fixed in DR24, in the newest target pixel data files that you will per-default download from KASOC. This timing error, resulting in a 66.184 seconds offset between the reported times in the data files and the correct time.
It is important to note that it is only the short cadence target pixel data that are affected, but remember when downloading Kepler data, to please pay attention to the data release number of the data, as the data can be affected by the timing error.
You can read more about the error on the following link:
http://archive.stsci.edu/kepler/timing_error.html
We have added a simple filter to the Data Search page which will allow you to filter out the incorrect Data Release 24 Short Cadence data from your data searches.
The filter, which is enabled by default, can be turned on and off under the "Basic Data" tab of the Data Search query page.
You can read more about the problem here:
http://keplergo.arc.nasa.gov/problem-with-dr24-short-cadence-data.html