# Transit photometry · Concept > Finding and measuring things that pass in front of a star by the dip in its light. Source: https://mysteriesdept.com/concepts/CPT0DECW02PHXR7/transit-photometry Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) --- [Concepts](https://mysteriesdept.com/concepts)Transit photometry Concept · astronomy · in 3 mysteries # Transit photometry Finding and measuring things that pass in front of a star by the dip in its light. [HD 139139, the "Random Transiter"](https://mysteriesdept.com/mysteries/hd-139139-random-transiter)[Tabby's star (KIC 8462852)](https://mysteriesdept.com/mysteries/tabbys-star)[1I/'Oumuamua](https://mysteriesdept.com/mysteries/oumuamua) A planet crossing its star's face blocks a small, regular fraction of the light; a telescope measuring the star's brightness over months sees the dips. Kepler and TESS found thousands of planets this way. Tabby's star and HD 139139 are on this site because their dips do not behave: irregular, too deep, or not repeating, which the usual causes do not produce. ## Where it comes up **[HD 139139, the "Random Transiter"](https://mysteriesdept.com/mysteries/hd-139139-random-transiter)** Finds transit-like dips of 0.75–8 hours in a light curve, measures how many K2-like dips the data could have caught, and calibrates false alarms on the same data. [Single-event dip search with injection-recovery and fair nulls](https://mysteriesdept.com/methods/MTH0DD2FEM3PXJB/single-event-dip-search-with-injection-recovery-and-fair)[Ten known dippers diluted by a factor of 15 do not resemble this light curve.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S50A670A/ten-known-dippers-diluted-by-a-factor-of-15-do-not-resemble)[The dips were first seen in the Kepler pipeline light curve and analysed in the independent K2SFF reduction.](https://mysteriesdept.com/mysteries/hd-139139-random-transiter/evidence/EVD0D79S1B46GYE/the-dips-were-first-seen-in-the-kepler-pipeline-light-curve)[TESS Sector 91 full-frame-image light curves at the position of HD 139139 (2025)](https://mysteriesdept.com/datasets/DAT0D79S7Y20VHM/tess-sector-91-full-frame-image-light-curves-at-the-position)[K2 Campaign 15 light curves of EPIC 249706694 (pipeline, K2SFF and EVEREST)](https://mysteriesdept.com/datasets/DAT0D79S7P81J3J/k2-campaign-15-light-curves-of-epic-249706694-pipeline-k2sff) **[Tabby's star (KIC 8462852)](https://mysteriesdept.com/mysteries/tabbys-star)** Joins DR7's per-exposure colour term to a star's light curve, classes plates by DASCH's colour-term bands, and asks whether a long-term offset survives on good-blue plates alone and whether residuals track the colour… [Colour-term stratification of a DASCH DR7 long-term offset](https://mysteriesdept.com/methods/MTH0DEC0S4G0XB7/colour-term-stratification-of-a-dasch-dr7-long-term-offset)[Observer-offset ensemble reduction of the AAVSO record](https://mysteriesdept.com/methods/MTH0DED7CM4S3AY/observer-offset-ensemble-reduction-of-the-aavso-record)[Sliding-box dip search with injection-recovery for TESS light curves](https://mysteriesdept.com/methods/MTH0DDYEH1HVCN2/sliding-box-dip-search-with-injection-recovery-for-tess)[Matched-comparison century-slope test for DASCH light curves](https://mysteriesdept.com/methods/MTH0DDYEGKBWKWV/matched-comparison-century-slope-test-for-dasch-light-curves)[ASAS-SN image-subtraction reconciliation: fade slopes, catalogue comparison, camera tie-in and depression check](https://mysteriesdept.com/methods/MTH0DEEB7M73CED/asas-sn-image-subtraction-reconciliation-fade-slopes)[No known or proposed stellar phenomenon explains all aspects of the light curve.](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0D8E7AMC4ZZR/no-known-or-proposed-stellar-phenomenon-explains-all-aspects) **[1I/'Oumuamua](https://mysteriesdept.com/mysteries/oumuamua)** [The light curve shows no secular change in spin, which is in tension with how outgassing comets spin up.](https://mysteriesdept.com/mysteries/oumuamua/evidence/EVD0CSKC2B22PP3/the-light-curve-shows-no-secular-change-in-spin-which-is-in)[The light curve and lateral motion are unlikely for a sail.](https://mysteriesdept.com/mysteries/oumuamua/evidence/EVD0CSKCNM832AG/the-light-curve-and-lateral-motion-are-unlikely-for-a-sail) ## Methods that use it 6 [Single-event dip search with injection-recovery and fair nulls](https://mysteriesdept.com/methods/MTH0DD2FEM3PXJB/single-event-dip-search-with-injection-recovery-and-fair) HD 139139, the "Random Transiter" MTH [Colour-term stratification of a DASCH DR7 long-term offset](https://mysteriesdept.com/methods/MTH0DEC0S4G0XB7/colour-term-stratification-of-a-dasch-dr7-long-term-offset) Tabby's star (KIC 8462852) MTH [Observer-offset ensemble reduction of the AAVSO record](https://mysteriesdept.com/methods/MTH0DED7CM4S3AY/observer-offset-ensemble-reduction-of-the-aavso-record) Tabby's star (KIC 8462852) MTH [Sliding-box dip search with injection-recovery for TESS light curves](https://mysteriesdept.com/methods/MTH0DDYEH1HVCN2/sliding-box-dip-search-with-injection-recovery-for-tess) Tabby's star (KIC 8462852) MTH [Matched-comparison century-slope test for DASCH light curves](https://mysteriesdept.com/methods/MTH0DDYEGKBWKWV/matched-comparison-century-slope-test-for-dasch-light-curves) Tabby's star (KIC 8462852) MTH [ASAS-SN image-subtraction reconciliation: fade slopes, catalogue comparison, camera tie-in and depression check](https://mysteriesdept.com/methods/MTH0DEEB7M73CED/asas-sn-image-subtraction-reconciliation-fade-slopes) Tabby's star (KIC 8462852) MTH ## Cite it ``` Mysteries Department. (2026). Transit photometry [Concept CPT0DECW02PHXR7]. https://mysteriesdept.com/r/CPT0DECW02PHXR7 ``` Key **CPT** 0DECW02PHXR7 Record Concept Field Astronomy Related [Light curve](https://mysteriesdept.com/concepts/CPT0DECW02VSSXN/light-curve) · [Dyson sphere](https://mysteriesdept.com/concepts/CPT0DECW03DJM9T/dyson-sphere) Version 2 Added by [apollo](https://mysteriesdept.com/u/apollo) [ Wikidata](https://www.wikidata.org/wiki/Q1095734) **How this page is made.** The definition is the site's, in its own words. “Where it comes up” is read from the answers, methods and evidence that name the concept. Related concepts [Light curve](https://mysteriesdept.com/concepts/CPT0DECW02VSSXN/light-curve)[Dyson sphere](https://mysteriesdept.com/concepts/CPT0DECW03DJM9T/dyson-sphere) The record Every record is open data. Take this one as JSON, with its links and its history. [JSON](https://mysteriesdept.com/api/v1/records/CPT0DECW02PHXR7)