× Sector 3 was reprocessed in May 2021, updating the background correction, manual exclude flags, timestamps, and input catalog. For more deatil please see the Reprocessing Information table below.

Sector 3 Information

For full data release notes see: DRN4, DRN42 (reprocessing). For a list of TIC IDs with noted issues, see this list.

Sector Summary

Sector dates: September 20 to October 17 2018

Pointing: Southern hemisphere

Days of Science Data Collection: 20.4

Days of Paused Data Collection: 1.12

Spacecraft Pointing (deg)

	RA	dec	roll
Spacecraft	36.31	-44.26	213.04
Camera 1	17.17	-12.22	293.55
Camera 2	28.46	-33.91	298.06
Camera 3	47.39	-53.85	131.45
Camera 4	90.0	-66.57	169.06

Orbit Summary

Orbits	Dates (UTC) Start - End	Cadence # Start - End	Momentum dumps
13	2018-09-20 - 2018-10-03	111297 - 120978	Every 2.5 days
14	2018-10-05 - 2018-10-17	121788 - 130988	Every 2.5 days

Sector Notes

Noted Issue	Description
Spacecraft Pointing	During sector 3 there were several experiments conducted on the attitude control system (ACS) to improve pointing stability. Tests were conducted during the perigee passages after orbits 12, 13 and 14, as well as the first 3 days of orbit 13 and the last 3 days of orbit 14. During these times, the ACS feedback loop was altered and the calibration parameters tuned. The jitter profile during these times differs substantially from the normal data collection mode, which used the same ACS configuration as in Sectors 1 and 2. Imaging and light curve data during these tests is provided for completeness, but has limited use for scientific applications. Valid data in the standard ACS configuration were collected between TJD 1385.8966 and 1395.4800 in orbit 13 and between TJD 1396.6050 and 1406.2925 in orbit 14, spanning ∼20.4 days of useful observations.
Scattered Light	In Sector 3, the main stray light feature is caused by the Earth rising above the sunshade near the end of each orbit, resulting in an enhancement of the stray light over parts of each camera’s FOV.
Timing precision and accuracy	The clock kernel used to process Sector 3 data has a slight error, resulting from extrapolation of timing measurements made during Sector 1. The reported TJD values in all data products are therefore offset by ∼1.2 seconds at the end of orbit 14 (2018-10-17 UTC).

Reprocessing Information: DRN42

During TESS’s primary mission several updates were made to various instrument models, algorithms, and pipeline parameters. Below we list what was updated and applied when reprocessing sectors 1-13. Please see DRN42 for a more comprehensive explanation of each update.

Update	Description
Instrument models updated:	Electronics model Reference Flux, PRF, and Linearity
Calibration Pipeline Module updates:	The 1D bias estimate is now split into two components, a time-dependent scalar correction and a static row-dependent correction. The first two overclock rows were also removed. The propagation of the uncertainty from the 2D bias model was changed. It is a static term and no longer applied to pixel data.
Pre-Search Data Conditioning Pipeline Module updates:	The parameters to calibrate the PDC goodness metrics were finalized.
Transiting Planet Search Pipeline Module updates:	An initial run of TPS is now used to identify problematic epochs that are assigned “deemphasis weights” in a second and final run of TPS.
Compute Optimal Aperture Pipeline Module updates:	The photometric apertures for stars with Tmag less than 11 were slightly increased.
Photometric Analysis Pipeline Module updates:	The sky background estimate was modified. A scalar offset is now applied that forces the dimmest background-corrected pixels to values near zero, if those pixels were significantly negative.
TESS Input Catalog update:	Targets were reprocessed with version 8 of the TIC. The change affected the apertures assigned to individual targets and the calculations for crowding (CROWDSAP) and flux fraction (FLUXFRAC), and as such the physical properties of TCEs derived from stellar parameters.
Timestamps update:	Timestamps were updated to account for previous drift errors and electronic effects. All data from Sectors 1–36 are now registered to a consistent time system.
New data flags:	All flags are now consistent with those described in DRN30.
Threshold Crossing Event issues:	The planet search of the reprocessed light curves produced a different set of TCEs from the original processed data. There is a high degree of overlap, but not every TCE from previous data releases was recovered. To differentiate between the initial release and this reprocessed data a "pipeline instance number" is included in the filenames of the dv-timeseries, dv-reports, ad dv-result xml files. Larger pin numbers indicate later versions of the software were used to produce the data products. The DR number is also included as a keyword in the export product headers (DATA_REL).