× Sector 1 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 1 Information

For full data release notes see: DRN1, DRN42 (reprocessing). For a list of TIC IDs with noted issues, see this list.

Sector Summary

Sector dates: July 25 to August 22 2018

Pointing: Southern hemisphere

Days of Science Data Collection: 27.9

Days of Paused Data Collection: 1.13

Spacecraft Pointing (deg)

	RA	dec	roll
Spacecraft	352.68	-64.85	222.15
Camera 1	324.57	-33.17	289.92
Camera 2	338.58	-55.08	299.88
Camera 3	19.49	-71.98	157.19
Camera 4	90.0	-66.56	224.19

Orbit Summary

Orbits	Dates (UTC) Start - End	Cadence # Start - End	Momentum dumps
9	2018-07-25 - 2018-08-08	70444 - 79968	Every 2.5 days
10	2018-08-09 - 2018-08-22	80782 - 90519	Every 2.5 days

Sector Notes

Noted Issue	Description
Scattered light	In Sector 1, the main stray light features to be aware of are: There is an oscillation in the background with a period of 1 day caused by the rotation of the Earth. The Moon gets quite close to the FOV of Camera 1 at the end of the sector. On the last day of observations, the angle between the Moon and the boresight of Camera 1 is <30◦ , which causes a the large spike.
Mars	Mars was near opposition during Sector 1 and landed in the field-of-view of Camera 1 for ∼2 days at the beginning of observations. Specifically, it is in Camera 1, CCD 4, output channel D, and visual inspection of the FFIs and target pixel files shows an extremely bright object with excess charge spread across the pixels in this output channel. As a consequence, photometry is unreliable in this section of the CCD in the first ∼510 cadences of the sector. See pgs. 7 and 8 of the DRN for more information.
Timing precision and accuracy	Due to an error in the spacecraft clock kernel, the two-minute cadence durations vary by ∼0.51 msec and the FFI durations vary by ∼7.8 msec. The changes in the durations are discontinuous and occur at reference points used to interpolate the conversion from space- craft time to TJD. However, these errors are well within TESS’s 1 second timing accuracy requirement.

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).