# APPLAUSE plate differential against matched comparison stars, on Gaia-synthetic residuals

> An independent fourth plate archive for the 1953-1969 step seen in DASCH DR7. Unlike Harvard, it has plates inside the 1953-1969 gap. Run 1 times on the…

Source: https://mysteriesdept.com/methods/MTH0DFQ1D4C7MWE/applause-plate-differential-against-matched-comparison-stars  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[Methods](https://mysteriesdept.com/methods)[Photographic photometry](https://mysteriesdept.com/methods?kind=statistics-and-information)APPLAUSE plate differential against matched comparison stars, on Gaia-synthetic residuals

Method · photographic photometry

# APPLAUSE plate differential against matched comparison stars, on Gaia-synthetic residuals

An independent fourth plate archive for the 1953-1969 step seen in DASCH DR7. Unlike Harvard, it has plates inside the 1953-1969 gap.

**Photographic photometry** Version **1.0** Licence **MIT1** runUsed on **1** mystery

## Questions it answers

- [Did the star fade over the twentieth century?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E77702V2V/did-the-star-fade-over-the-twentieth-century)

## Code Python

[Download module (.py)](https://mysteriesdept.com/files/private/dc1fe9da6ccafada7084e8ec63eb9718c9674f81655e929ea716041f3c9a7ece)`fetch_applause.py`[View source](https://mysteriesdept.com/files/private/dc1fe9da6ccafada7084e8ec63eb9718c9674f81655e929ea716041f3c9a7ece)

## Runs and results 1 run

| Run | Mystery | Measured | Result | Against | Date |
|---|---|---|---|---|---|
| RUN0DFQ2HNJMYAC | Tabby's | Median differential after 1969 minus before 1953 (mag), ranked among comparison stars | {'null': '0.012 ± 0.104', 'step': 0.154, 'frac_ge': 0.05, 'slope_null': '-0.02 ± 0.41', 'grid_step_range': [0.131, 0.178], 'system_mode_step': 0.037, 'slope_mag_century': 0.38} | DASCH_DR7_step +0.09 (about 2 sigma vs matched stars) · Sonneberg_Hippke2017 constant to 0.03-0.04 mag/century · Enke2024_APPLAUSE_global no decade-scale variation | |

## 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)1 dataset** APPLAUSE DR4 plate photometry of KIC 8462852 and 182 matched/control comparison stars, 1915-1981

## References

1. [arXiv:1605.02760 (preprint, May 2016). DASCH light curves of 644 F stars (337 Tycho-2 F3 IV/V in APASS B, 307 KIC analogues in g). The population's slope statistics are over-dispersed until a break at 1970 (the Menzel gap) is modelled; the target's full-series B slope of 0.129 +/- 0.026 mag per century splits into two flat segments and a jump; 11 of 644 stars still exceed 5 sigma after the split. Concludes that several apparent F-star fades are artefacts of the gap and that KIC 8462852 is consistent with constant flux.](https://mysteriesdept.com/sources/SRC0DDYCEJ03QA3/the-stability-of-f-star-brightness-on-century-timescales)
1. [APPLAUSE DR4: about 94,000 plates from Hamburg, Bamberg, Potsdam, Tautenburg, Tartu and the Vatican, calibrated against Gaia EDR3 with PyPlate and served over TAP. The paper builds a light curve of KIC 8462852 and reports no evidence of variation on decade timescales. This department re-reduced the same data against matched comparison stars in Session 4.](https://mysteriesdept.com/sources/SRC0DFQ0WSSXYNZ/archives-of-photographic-plates-for-astronomical-use)

[Download module](https://mysteriesdept.com/files/private/dc1fe9da6ccafada7084e8ec63eb9718c9674f81655e929ea716041f3c9a7ece)

Category

Photographic photometry

Version

1.0 · 2 Nov 2026

Licence

MIT

Language

Python

Inputs

APPLAUSE DR4 detections and plate metadata (DAT0DFQ1389EQ9V)

Output

applause_results.json (slope, step, null ranks), applause_null.csv, the target differential series, the robustness grid, a within-telescope check and a figure

Cite

[BibTeX](https://mysteriesdept.com/methods/MTH0DFQ1D4C7MWE/applause-plate-differential-against-matched-comparison-stars/cite.bib) · [APA](https://mysteriesdept.com/methods/MTH0DFQ1D4C7MWE/applause-plate-differential-against-matched-comparison-stars/cite.txt)

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Authors

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