Sector 18



× Sector 18 was reprocessed in September 2020, updating timestamps, photometric apertures, data anomaly flags, and threshold crossing events. For more deatil please see the Reprocessing Information table below.
× Warning for Sector 18: Due an eclipse of the spacecraft by the Earth no data was taken for 6.2hrs in orbit 43. The FFI timestamps for Sector 18 are incorrect. The readouts of the four cameras are staggered by 0.5 sec.

Sector 18 Information

For full data release notes see: DRN25, DRN30 (reprocessing). For a list of TIC IDs with noted issues, see this list.

Update:

The FFI timestamps for Sector 18 are incorrect. The readouts of the four cameras are staggered by 0.5 seconds in the following order: Camera 1 (0 second offset), Camera 3 (0.5 second offset), Camera 4 (1.0 second offset), and Camera 2 (1.5 second offset). Although these offsets are correctly incorporated into the timestamps in the target pixel files and light curves, the FFI time stamps are not corrected for the staggered readout. For Sector 1 through Sector 18, the offsets for each camera can be added to the TSTART and TSTOP header values in the FFIs to correct the issue.

In addition, the TSTOP header values in the target pixel files, light curve files, and FFIs are overestimated by 20 ms, and the TIME column of the target pixel files and light curve files are overestimated by 10 ms.

Sector Summary

  • Sector dates: November 3 to November 27 2019
  • Pointing: Northern hemispher
  • Days of Science Data Collection: 23.12
  • Days of Paused Data Collection: 1.00



    • Spacecraft Pointing (deg)

    RA dec roll
    Spacecraft 16.11 67.96 40.55
    Camera 1 44.14 35.61 107.46
    Camera 2 30.86 57.93 117.35
    Camera 3 344.62 75.0 340.53
    Camera 4 270.0 66.56 52.16



    Orbit Summary

    Orbits Dates (UTC)

    Start - End

    		 Cadence #

    Start - End

    		 Momentum dumps
    43 2019-11-03 - 2019-11-14 405501 - 413989 Every 4.25 days
    44 2019-11-15 - 2019-11-27 414711 - 423054 Every 4.5 days



    Sector Notes

    Noted Issue Description
    Instrument shutdown The spacecraft passed through the shadow of the Earth at the start of orbit 43. During this time, the instrument was turned off and no data were collected for 6.2 hours between TJD 1791.1115 and 1791.3699. The thermal state of the spacecraft changed during this time, and trends in the raw photometry and target positions are apparent after data collection resumed. However, the pipeline effectively removes these trends in the PDC light curves.
    Spacecraft pointing Camera 4 alone was used for guiding in orbit 43, and both Camera 1 and Camera 4 were used for guiding in orbit 44.
    Scattered light In Sector 18, the Moon and Earth move close enough to the field of view of Camera 1 at the end of orbit 43 to briefly saturate the detector.



    Reprocessing Information: DRN30

    The data products of sectors 14 to 19 were generated using version 4.0 of the science processing pipeline and conform to the final set of data anomaly flags. A detailed description of the changes in the data products can be found in DRN30, but a summary is provided here.

    Update Description
    Timestamps: For 2 minute cadence and FFI data the timestamps were made more accurate. The differences between reprocessed data and previous data releases are less than 2.0 seconds in all cases.
    Photometric apertures: The apertures were increased in size for targets with Tmag less than 11.
    Data Anomaly Flags: Three new flags were added to mitigate the effects of scattered light;

    - Cadences with strong scattered light signals or saturation effects that corrupt the calibration data are flagged and removed from analysis.

    - Scattered light data anomaly flags are customized for each target, and flagged automatically based on the local background level.

    - Cadences with insufficient targets to derive cotrending basis vectors are flagged and the PDCSAP FLUX light curves are set to NULL at these times

    The modifications to the data anomaly flags also changed the cotrended light curves produced by PDC. The changes also result in new cotrending basis vectors for each CCD in each sector. The scattered light flags are now only applied to the PDCSAP FLUX light curves.
    Threshold Corssing Event issue: The planet search of the reprocessed light curves produced a different set of TCEs from the original processed data. Although there is a high degree of overlap between the original and reprocessed data (∼83% of targets produced TCEs in common), new TCEs were produced and not every TCE from previous data releases was recovered.