# A bounded Kepler light curve for TrES-2

The CSV and JSON contain the same **31 processed observations** of TrES-2 / Kepler-1 (KIC 11446443), taken in Kepler quarter 0, 2009. They are neither raw detector counts nor simulated observations.

**Credit:** NASA Kepler mission; NASA Ames pipeline; Mikulski Archive for Space Telescopes (STScI). Funding for the Kepler mission was provided by the NASA Science Mission Directorate. This page uses publicly available mission data, separate from the website’s code license. See [MAST data use](https://archive.stsci.edu/publishing/data-use) and [Kepler public-data availability](https://archive.stsci.edu/kepler/getting_started.html).

Source product: [`kplr011446443-2009131105131_llc.fits`](https://archive.stsci.edu/missions/kepler/lightcurves/0114/011446443/kplr011446443-2009131105131_llc.fits), data release 25, source pipeline release 9.3.21, retrieved 27 September 2026. Source SHA-256: `e1699c5dd0089c35d908b711b302f72ba974edc68e030dae3e9a65d5065f7d0c`. Time conventions, column definitions and pipeline corrections are described in [Thompson, S. E., and Fraquelli, D. (2014), *Kepler Archive Manual*, KDMC-10008-005, §§ 2.1.2 and 2.3.1, pp. 12–13 and 15–19 (PDF)](https://archive.stsci.edu/kepler/manuals/archive_manual_01jun16.pdf). The source FITS header supplies the exact release, cadence and column definitions for this product.

Selection: BKJD 124.89–125.59 inclusive; SAP_QUALITY = 0; finite positive PDCSAP_FLUX and PDCSAP_FLUX_ERR. Missing or rejected values are omitted and never filled. PDCSAP is the pipeline-corrected simple aperture photometry product. Its corrections precede our extraction.

BKJD is BJD in TDB minus 2,454,833 days. Subtracting 125.24 and multiplying by 24 gives the displayed hours. That origin is a rounded guide, not an estimated mid-transit time. The cadence is 29.4243814323648 minutes (FITS TIMEDEL × 1440); its finite duration is not modeled by the ideal interactive curve.

Normalization: divide both PDCSAP_FLUX and PDCSAP_FLUX_ERR by **406130.375 electrons per second**, the median of the 17 selected points satisfying |BKJD − 125.24| ≥ 0.15 days. No further detrending, smoothing, interpolation, binning, phase folding or model fitting is performed.

| Column | Unit / meaning |
| --- | --- |
| bkjd | BJD TDB minus 2454833, days |
| hours_from_origin | Hours from BKJD 125.24 |
| normalized_flux | Dimensionless processed flux divided by the selected baseline |
| normalized_flux_error | Reported 1σ pipeline error divided by the same baseline |
| pdcsap_flux | Original pipeline-corrected flux, electrons/second |
| pdcsap_flux_error | Original pipeline 1σ error, electrons/second |
| quality | Original SAP_QUALITY bit mask; every retained value is zero |

The error bars do **not** include baseline uncertainty, correlated systematics or transit-model uncertainty. They are often smaller than the plot symbols. The plot displays each retained observation individually. It is an illustration of a real dip, not a new parameter measurement or independent planet confirmation.

Reproduce with Python 3 (standard library only), from the repository root:

```sh
python3 scripts/universe/prepare-transit-data.py --download
```

For an offline reproduction, the repository retains the exact original FITS input:

```sh
python3 scripts/universe/prepare-transit-data.py --input scripts/universe/fixtures/kplr011446443-2009131105131_llc.fits
```

Add `--check` for a read-only comparison instead of rewriting the derivative. The script verifies the source hash, target, quarter, release and column layout before creating these bounded files. Acquisition is an explicit maintenance command and is never needed to read or build the site.