Mission Overview
TESS Image CAlibrator Full Frame Images ("TICA")
Primary Investigator: Michael Fausnaugh
HLSP Authors: Michael Fausnaugh, Christopher Burke, George Ricker, Roland Vanderspek
Released: 2021-02-02
Updated: 2021-02-02
Primary Reference(s): Fausnaugh et al. 2021
Citations: See ADS Statistics
Overview
TESS images that serve as the input to the MIT Quick Look Pipeline (QLP) are provided here. The team uses a Python package ("tica"), to calibrate the raw pixels and apply astrometric registration in the form of World Coordinate Solutions.
Data Release 1
The first data release consists of calibrated full frame images from Sectors 27 - 30.
Data Products
All TICA calibrated full frame image files are sorted into directories based on the Sector, as a four-digit, zero-padded string preceded by an 's'. They are then further sorted into subdirectories based on the Camera and CCD numbers. For example, the files associated with Sector 27 for Camera 2, CCD 3, go into this subdirectory:
s0027/cam2-ccd3/
The catalog of reference stars used to define the WCS are stored in a subdirectory called "ref-stars/" within each Sector directory.
The calibrated full frame images have the following naming convention:
hlsp_tica_tess_ffi_<sector>-<orbit>-<cadence>-<cam>-<ccd>_tess_v01_<extension>
where:
- <sector> = The Sector number as a four-digit, zero-padded number preceded by an 's', e.g., 's0027' for Sector 27.
- <orbit> = The relative orbit number within this Sector, either "o1" or "o2". Note that this does not correlate to the absolute Orbit Number that is tracked and reported in the Data Release Notes and in mission-produced products.
- <cadence> = The cadence number, as an eight-digit, zero-padded integer, equal to the FFIINDEX header keyword for mission-produced FFIs.
- <cam> = The camera number (1-4), e.g., "cam2" for Camera #2.
- <ccd> = The CCD number (1-4) for that camera, e.g., "ccd1" for CCD #1.
- <extension> = "img.fits" for the calibrated full frame images.
The WCS calibration reference star catalogs have the following naming convention:
hlsp_tica_tess_ffi_<sector>-<cadence>-<cam>-<ccd>_tess_v01_<extension>
where:
- <sector> = The Sector number as a four-digit, zero-padded number preceded by an 's', e.g., 's0027' for Sector 27.
- <cadence> = The cadence number, as an eight-digit, zero-padded integer, equal to the FFIINDEX header keyword for mission-produced FFIs.
- <cam> = The camera number (1-4), e.g., "cam2" for Camera #2.
- <ccd> = The CCD number (1-4) for that camera, e.g., "ccd1" for CCD #1.
- <extension> = "cat.h5" for the catalogs of stars used to refine the World Coordinate System for the TICA full frame images.
Description of FFI Header Keywords
| Keyword | Header Card | Notes |
|---|---|---|
| CRM_N | Window for CRM min/max rejection | For each pixel, the high and low value in a series of "CRM_N" 2-second exposures are rejected in order to remove cosmic rays. |
| ORBIT_ID | Orbit ID, not a physical orbit | Only unphysical for commissioning or engineering data. |
| ACS_MODE | Attitude Control System mode | Either "FP" for Fine Pointing mode or "CPI" for Course Pointing Inertial mode. |
| SC_RA | Predicted RA | Commanded pointing for the Spacecraft. Note that orbit 2 is shifted a few arcseconds relative to orbit 1. |
| SC_DEC | Predicted Dec | Commanded pointing for the Spacecraft. Note that orbit 2 is shifted a few arcseconds relative to orbit 1. |
| SC_ROLL | Predicted roll | Commanded pointing for the Spacecraft. Note that orbit 2 is shifted a few arcseconds relative to orbit 1. |
| SC_QUATX | Predicted S/C quaternion x | Commanded pointing for the Spacecraft. Note that orbit 2 is shifted a few arcseconds relative to orbit 1. |
| SC_QUATY | Predicted S/C quaternion y | |
| SC_QUATZ | Predicted S/C quaternion z | |
| SC_QUATQ | Predicted S/C quaternion q | |
| TJD_ZERO | JD-TDB epoch for which TJD = 0 | Corresponds to 2014 December 8 12-00-00 UTC. |
| STARTTJD | Beginning of integration in TJD (days) | Time system is in the spacecraft reference frame. |
| MIDTJD | Mid TJD of exposures | |
| ENDTJD | End of integration in TJD | |
| EXPTIME | Effective exposures corrected for CRM |
Equal to "INT_TIME"*0.8*0.99. Includes the effects of cosmic ray mitigation and frame transfer. |
| INT_TIME | Seconds of integration | Total seconds after integration of 2 second exposures. |
| PIX_CAT | ADHU target pixel bitmask ID | Spacecraft configuration table. |
| REQUANT | Requant table id | Spacecraft configuration table, used for data compression. |
| DIFF_HUF | Huffman table for differenced data | Spacecraft configuration table, used for data compression. |
| PRIM_HUF | Huffman table for undifferenced data | Spacecraft configuration table, used for data compression. |
| QUAL_BIT | Quality flags | Place-holder field; currently not implemented. |
| SPM | SPM number (0, 1, 2, 3) | Science Processing Module. Each TESS data mode is collected by a different SPM number. For the FFIs, SPM=2. |
| TIME | Beginning of integration in SCT (seconds) | Second counter for spacecraft on-board clock. |
| CADENCE | Cadence number since start of data collection | Cadence 0 is approximately defined as the time that TESS was launched, 2018 April 18 23-00-00 UTC. |
| CRM | Whether or not cosmic ray were mitigated | If true, cosmic rays were mitigated on-board. |
| CAMNUM | Camera Number | Camera Number (1 through 4). |
| CCDNUM | CCD number | CCD number (1 through 4). |
| SCIPIXS | Pixel indices with science data. Pixels outside of this region are collateral pixels, used for calibration. Always equal to "[45:2092,1:2048]". | |
| GAIN_A | e/ADU for CCD Sector A | Conversion factor of ADU to photoelectrons. |
| GAIN_B | e/ADU for CCD Sector B | |
| GAIN_C | e/ADU for CCD Sector C | |
| GAIN_D | e/ADU for CCD Sector D | |
| UNITS | Units (ADU or electrons) | Always equal to "electrons". |
| EQUINOX | Always set to epoch 2000.0. | |
| INSTRUME | Always set to "TESS Photometer". | |
| TELESCOP | Always set to "TESS". | |
| FILTER | Always set to "TESS". | |
| MJD-BEG | Same as STARTTJD but in JD. | |
| MJD-END | Same as ENDTJD but in JD. | |
| TESS_X | Spacecraft X coord, J2000 (km from barycenter) | Position of TESS used for barycentric correction. Matches SPICE conventions: axes are aligned with J2000 ICRS, but the origin is centered at the solar system barycenter. X-axis points at vernal equinox. |
| TESS_Y | Spacecraft Y coord, J2000 (km from barycenter) | As above. Y-axis is orthogonal to X. |
| TESS_Z | Spacecraft Z coord, J2000 (km from barycenter) | As above. Z-axis points at north celestial pole. |
| TESS_VX | Spacecraft X velocity (km/s) | Velocity relative ot barycenter. |
| TESS_VY | Spacecraft Y velocity (km/s) | Velocity relative ot barycenter. |
| TESS_VZ | pacecraft Z velocity (km/s) | Velocity relative ot barycenter. |
| RA_TARG | Right Ascension of center of image [deg.]. | Same as CRVAL1, matches MAST convention. |
| DEC_TARG | Declination of center of image [deg.]. | Same as CRVAL2, matches MAST convention. |
| RMSA | WCS fit resid all targs [arcsec] | Metric for quality of WCS fit. |
| RMSB | WCS fit resid bright (Tmag<10) targs [arcsec] | |
| RMSF | WCS fit resid faint (Tmag>10) targs [arcsec] | |
| RMSAP | WCS fit resid all targs [pixel] | |
| RMSBP | WCS fit resid bright (Tmag<10) targs [pixel] | |
| RMSBF | WCS fit resid faint (Tmag>10) targs [pixel] | |
| RMSX0 | WCS fit resid extra 0 [arcsec] | |
| RMSX1 | WCS fit resid extra 1 [arcsec] | |
| RMSX2 | WCS fit resid extra 2 [arcsec] | |
| RMSX3 | WCS fit resid extra 3 [arcsec] | |
| WCSGDF | Fraction of control point targs valid | |
| CTRPCOL | Subregion analysis blocks over columns | For efficient searching, queries to MAST are broken into subregions. |
| CTRPROW | Subregion analysis blocks over rows | As above. |
| FLXWIN | Width in pixels of Flux-weight centroid region | |
| CHECKSUM | HDU checksum | |
| DATASUM | Data unit checksum |
Data file types:
| _img.fits | Calibrated full frame image. |
| _cat.h5 | Catalog of stars used to refine the WCS for a given Sector+Camera+Chip. These file formats are in HDF5. |
Data Access
The calibrated full frame images and catalogs of WCS reference stars are available as bulk download scripts for each Sector via the table below. The scripts use curl, which is likely already installed on many machines, and if not, is freely available as open source software. The bulk download scripts for the mission-produced products also make use of curl. You can run each shell script directly in a terminal to retrieve the full set of files, or use a selected subset of the script: each line in the script downloads one TICA file.