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K2 Online Ancillary Files

As was done for Kepler, several types of online ancillary data files are made available to users. The currently available ones are described below with links to the corresponding subdirectories of the K2 directory. Note that the Long and Short Cadence Collateral (KLL & KLS) files, Artifact Removal Pixel (KAP) files, and Background Pixel files (KBG) are stored elsewhere but can be retrieved using the FFI & Ancillary Data search form. These file types are documented in the Kepler Archive Manual and the differences for K2 products are noted in the K2 Data Release Notes.

  • Cotrending Basis Vectors (CBV) Files
    The CBVs may be used to mitigate instrumental signatures in K2 light curves when the PDC light curves are inadequate. CBVs are available for most campaigns starting with Data Release 5 (see the table at archive.stsci.edu/k2/cbv.html).

  • Full Frame Image (FFI)
    Full frame images of the K2 fields are typically taken twice during each campaign to confirm the field of view, assess photometer health, and facilitate calibration. The FFI files contain both raw and calibrated images as well as uncertainties. They can be downloaded using the browser at the above link, anonymous ftp at /pub/k2/ffi, or via the FFI & Ancillary Data search form.

    To display individual channels from any of the FFI images, and overlay various catalogs, see the FFI_Display page.

  • SPICE Kernels for K2
    The latest SPICE kernels (i.e., the bsp and tsc binary files) can be used to calculate the Kepler spacecraft ephemeris. These files are available via anonymous ftp at /pub/k2/spice, or via the browser at the above link. See the Navigation and Ancillary Information Facility (NAIF) web site for information on using SPICE Kernels.

  • Thruster Firings
    Starting with Data Release 5, the QUALITY flags included in the light curve and target pixel FITS files indicate cadences at which thrusters fired, or may have fired. Since some campaigns are yet to be reprocessed and others have no light curve files (e.g., C0, C2, C9a, C9b,C10a) these flags are provided in csv format with one line per cadence for each cadence type. Each line utilizes a comma-separated format and reports: cadence number, definite thruster firing flag, and possible thruster firing flag. Note these files may contain cadence gaps for periods of time when standard cadence data was not being collected; typically these correspond to data download periods or the collection of FFIs. (See Table 2-3 in the Kepler Archive manual for the definitions of these new bit flags).

  • C0 Raw Cadence Data
    C9 Raw Cadence Data
    C10 Raw Cadence Data
    C11 Raw Cadence Data
    C12 Raw Cadence Data
    These raw cadence data were released immediately after download from the Kepler spacecraft to facilitate time-critical investigations which would be unduly delayed by waiting for the pipeline-processed data that contain both calibrated and uncalibrated pixels in the standard TPF format.

    These raw cadence data consist of multiple components, including target pixels, collateral pixels, and pixel mapping reference files. For more information on format and usage, see the document KADN-26315.pdf, and consider using Kadenza to convert these raw data to a more user-friendly file format. Note that the C12 data have not yet been received.

  • Two-wheel Concept Engineering Test Data
    The data from a 9-day engineering test conducted before Campaign 0 have been made available as uncalibrated TPFs. These files can be downloaded individually or as .tgz files (there are 17 targets in the 4 GB short cadence compressed file and 2,079 targets in the 16 GB long cadence compressed file). To download from the browser use the link above, or ftp to archive.stsci.edu and cd to /pub/k2/eng. The individual files can be found in subdirectories labelled "short_cadence" and "long_cadence". The .csv files provide a brief description of why these targets were observed and map their engineering IDs to their locations and estimated Kepler magnitudes.

  • Download Scripts
    These WGET scripts allow light curve or target pixel file data to be downloaded for a particular program ID. These scripts should be downloaded to the users' computer and run from its command line. They require WGET to be installed on the users' computer.

  • Previews
    Previews are various size png plot files showing K2 light curves.