# TESS sector 56 per-window quality record

Status: diagnostic record for human verification. This document describes cadence availability and per-window column statistics in the committed sector 56 light curve. It is not a detection or a transit timing measurement.

Target: HD 209458 b (TIC 420814525), sector 56.

## Inputs

| Input | Repository path | SHA-256 |
| --- | --- | --- |
| Light curve | `research/tess-timing/data/real-run/lightcurve.fits` | `1b76b4a4b73e24954fa6e29a7e28a174685113ecdbad1bf10ef0e7b766ce99e9` |
| Target pixel file | `research/tess-timing/data/real-run/tpf.fits` | `2b5bd6ee4747cfe0c5405c869b871064fd74e4b5f0521c4e6be9fdc2b5c96030` |
| Windows record | `research/tess-timing/data/real-windows-run/windows.json` | `707971643ab01be668b3c62a6cf685036e1baaf983461c975a80b8cf184bd675` |

Both FITS primary headers report TICID 420814525 and SECTOR 56. The light curve and target pixel file TIME columns match row for row. The target pixel file is used for identity and time coverage only; no pixel photometry, contamination ratio, or nearby-source count is computed.

## Window definition

- Window source: `research/tess-timing/data/real-windows-run/windows.json` (the eight predicted mid-transit times, read without re-deriving them).
- Each window is `centre_btjd - 0.5 d <= BTJD <= centre_btjd + 0.5 d`, inclusive.
- The 0.5 d half-width is a fixed diagnostic interval. It is not a transit duration and it is not fitted to the data.
- Quality mask: 175 (bits 1, 2, 4, 8, 32, 128).
- Nominal cadence: 120.0 s; gap threshold: 180.0 s (1.5 times the cadence).
- Gaps are counted on finite TIME values before the quality mask inside each window.

## Coverage per window

| Cycle | Centre BTJD | Window start | Window end | Before mask | After mask | Removed | SAP finite | PDCSAP finite | Gaps | Longest gap (s) |
| ---: | ---: | ---: | ---: | ---: | ---: | ---: | ---: | ---: | ---: | ---: |
| 2317 | 2826.779903 | 2826.279903 | 2827.279903 | 720 | 720 | 0 | 720 | 720 | 0 | 0.000000 |
| 2318 | 2830.304652 | 2829.804652 | 2830.804652 | 720 | 720 | 0 | 720 | 720 | 0 | 0.000000 |
| 2319 | 2833.829400 | 2833.329400 | 2834.329400 | 720 | 720 | 0 | 720 | 720 | 0 | 0.000000 |
| 2320 | 2837.354149 | 2836.854149 | 2837.854149 | 720 | 720 | 0 | 720 | 720 | 0 | 0.000000 |
| 2321 | 2840.878897 | 2840.378897 | 2841.378897 | 720 | 720 | 0 | 720 | 720 | 0 | 0.000000 |
| 2322 | 2844.403646 | 2843.903646 | 2844.903646 | 720 | 720 | 0 | 720 | 720 | 0 | 0.000000 |
| 2323 | 2847.928395 | 2847.428395 | 2848.428395 | 720 | 719 | 1 | 719 | 719 | 0 | 0.000000 |
| 2324 | 2851.453143 | 2850.953143 | 2851.953143 | 720 | 720 | 0 | 720 | 720 | 0 | 0.000000 |
| All | - | - | - | 5,760 | 5,759 | 1 | 5,759 | 5,759 | 0 | - |

The per-window counts reconcile: before mask equals after mask plus removed for every window, and each column of the totals equals the sum over the eight non-overlapping windows.

## Background per window

SAP_BKG over cadences that pass the quality mask and have a finite background value.

| Cycle | Cadences | Median | 5th percentile | 95th percentile | 5 to 95 range |
| ---: | ---: | ---: | ---: | ---: | ---: |
| 2317 | 720 | 2495.103516 | 2477.421912 | 2507.585828 | 30.163916 |
| 2318 | 720 | 2802.246338 | 2718.167749 | 2837.684644 | 119.516895 |
| 2319 | 720 | 3224.441772 | 2983.439624 | 3306.281873 | 322.842249 |
| 2320 | 720 | 4085.784424 | 2860.890137 | 4794.700879 | 1933.810742 |
| 2321 | 720 | 2494.483521 | 2477.468567 | 2505.924927 | 28.456360 |
| 2322 | 720 | 2705.704102 | 2677.810718 | 2745.587000 | 67.776282 |
| 2323 | 719 | 2918.290283 | 2865.350049 | 2987.564111 | 122.214062 |
| 2324 | 720 | 3914.925903 | 3752.848608 | 4512.850220 | 760.001611 |

## Centroid per window

MOM_CENTR1 and MOM_CENTR2 over cadences that pass the quality mask and have a finite value. Peak-to-peak is the maximum minus the minimum in the window.

| Cycle | MOM_CENTR1 cadences | MOM_CENTR1 median | MOM_CENTR1 peak-to-peak | MOM_CENTR2 cadences | MOM_CENTR2 median | MOM_CENTR2 peak-to-peak |
| ---: | ---: | ---: | ---: | ---: | ---: | ---: |
| 2317 | 720 | 1867.037924 | 0.013729 | 720 | 357.581364 | 0.015752 |
| 2318 | 720 | 1867.052311 | 0.027331 | 720 | 357.584550 | 0.026395 |
| 2319 | 720 | 1867.064981 | 0.021001 | 720 | 357.555542 | 0.014145 |
| 2320 | 720 | 1867.091238 | 0.024433 | 720 | 357.557811 | 0.027067 |
| 2321 | 720 | 1867.077461 | 0.013282 | 720 | 357.615396 | 0.010800 |
| 2322 | 720 | 1867.098381 | 0.017705 | 720 | 357.614156 | 0.020066 |
| 2323 | 719 | 1867.117052 | 0.018717 | 719 | 357.616566 | 0.014563 |
| 2324 | 720 | 1867.142686 | 0.017396 | 720 | 357.608901 | 0.012895 |

## Reproduction

```
python research/tess-timing/scripts/real_window_qc.py
python research/tess-timing/scripts/real_window_qc.py --check
python -m pytest research/tess-timing/tests/test_real_window_qc.py -q
```

## Limits

- Diagnostic only. This record describes cadence availability and per-window column statistics for the committed sector 56 light curve. It is not a detection, a transit measurement, or a research result.
- No contamination ratio and no nearby-source count are computed because no source catalogue is committed in this repository.
- No detrending, transit fit, folding, or transit timing measurement is performed.
- Window centres are the eight predicted mid-transit times read from the committed windows record. They are not measured transit times.
- SAP_BKG and MOM_CENTR statistics are per-window summaries after the 175 quality mask; they are not calibrated astrophysical quantities.
- Gap counts use finite TIME values inside each window before the quality mask, with a fixed 180 s threshold (1.5 times the 120 s cadence).
- No target ranking, detection, or novelty claim is made.

Generated by `research/tess-timing/scripts/real_window_qc.py` from the committed sector 56 products and prediction record. Offline; no archive, catalogue, or network request is made.