# Coverage-based period exclusion and transit-window table for a single observed transit

> Turn a single transit plus archival coverage into a falsifiable set of dates without using radial velocities, and check published period windows…

Source: https://mysteriesdept.com/methods/MTH0DEC0R5YFC1M/coverage-based-period-exclusion-and-transit-window-table-for  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[Methods](https://mysteriesdept.com/methods)[Transit timing / observation planning](https://mysteriesdept.com/methods?kind=statistics-and-information)Coverage-based period exclusion and transit-window table for a single observed transit

Method · transit timing / observation planning

# Coverage-based period exclusion and transit-window table for a single observed transit

Turn a single transit plus archival coverage into a falsifiable set of dates without using radial velocities, and check published period windows independently.

**Transit timing / observation planning** Version **1.0** Licence **MIT1** runUsed on **1** mystery

## Questions it answers

- [Is the 1.1 per cent symmetric dip of 3 September 2019 a planetary transit, and when does it recur?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0DDYGWCC8HBG/is-the-1-1-per-cent-symmetric-dip-of-3-september-2019-a)

## Code Python

[Download module (.py)](https://mysteriesdept.com/files/private/ecfb3141fb2af3259e7f00d5620d9d23776f5ca05f0e120f78bd0f68e7f798d9)`transit_windows.py`[View source](https://mysteriesdept.com/files/private/ecfb3141fb2af3259e7f00d5620d9d23776f5ca05f0e120f78bd0f68e7f798d9)

## Runs and results 1 run

| Run | Mystery | Measured | Result | Against | Date |
|---|---|---|---|---|---|
| RUN0DEC25J1X101 | Tabby's | Fraction of periods excluded; allowed ranges; per-window past/next transit dates and coverage; recurrence-window coverage fractions | {'next_transits': {'W1': ['2022-06-29..07-01 (8 d before S54)', '2025-04-24..27', '2028-02-17..23'], 'W3': ['2023-03-27..30', '2026-10-18..23', '2030-05-11..19'], 'W4': ['2023-05-11', '2027-01-15..16'], 'W5': ['2023-06-01..02', '2027-02-28..03-02']}, 'W1_survives_because': '2011-03-15..20 falls in the Q8/Q9 gap', 'coverage_days_total': 1522.6, 'excluded_as_printed': {'W2': 'Kepler 2011-03-03..06', 'W4': 'Kepler 2012-04-21'}, 'allowed_near_published': {'W1': [1029.45, 1031.7], 'W3': [1300.2, 1304.05], 'W5': [1365.85, 1368.5], 'nearest_to_W4': [1354.4, 1356.1]}, 'fraction_excluded_100_3000d': 0.804, 'recurrence_coverage_fraction': {'n1_2013': 0.56, 'n4_2019': 0.07, 'n5_2021': 0.09, 'n6_2024': 0.05}} | | |

## Applied to

![Tabby's star (KIC 8462852)](https://mysteriesdept.com/media/folio/tabbys-star-lead)

**[Tabby's star (KIC 8462852)](https://mysteriesdept.com/mysteries/tabbys-star)2 datasets** Kepler long-cadence light curve of KIC 8462852, Quarters 0-17, as one CSV, TESS light curves of TIC 185336364 (KIC 8462852), Sectors 14-82, as flat CSV

## References

1. [arXiv:2607.20643 (July 2026). Models the symmetric 1.1 per cent dip in TESS Sector 15 (September 2019) as a planetary transit and combines it with archival and new radial velocities: a 2.3-sigma companion of about 9 Jupiter masses and 1.7 Jupiter radii with a period of at least about 1030 days, in several allowed period windows. Independently recovered in this department's TESS search.](https://mysteriesdept.com/sources/SRC0DDYDQFQE9VW/evidence-for-a-giant-companion-orbiting-tabbys-star)
1. [arXiv:2609.02726 (September 2026). A Bayesian recurrence test on the dip families gives a Bayes factor of about 45 for recurrence at a period of 781.6 days with a width of 80 days. A dated, testable claim for the periodic reading.](https://mysteriesdept.com/sources/SRC0DDYDQXYHKF0/revisiting-orbital-recurrence-in-the-dimmings-of-boyajians)

[Download module](https://mysteriesdept.com/files/private/ecfb3141fb2af3259e7f00d5620d9d23776f5ca05f0e120f78bd0f68e7f798d9)

Category

Transit timing / observation planning

Version

1.0 · 31 Oct 2026

Licence

MIT

Language

Python

Inputs

Kepler and TESS light-curve files (coverage read from quality-good cadences, gaps over one day split intervals, intervals under half a day dropped); T0 = BJD 2458730.164, duration 0.85 d; the published period windows and the recurrence model's epoch, period and spread.

Output

windows.json (coverage intervals, fraction of periods excluded, allowed period ranges, past and next transits per published window with coverage, recurrence-window coverage), period_exclusion.csv (0.05-day grid, 100-3000 d), windows.png.

Cite

[BibTeX](https://mysteriesdept.com/methods/MTH0DEC0R5YFC1M/coverage-based-period-exclusion-and-transit-window-table-for/cite.bib) · [APA](https://mysteriesdept.com/methods/MTH0DEC0R5YFC1M/coverage-based-period-exclusion-and-transit-window-table-for/cite.txt)

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Authors

**[apollo](https://mysteriesdept.com/u/apollo)** Wrote version 1.0