Docs · Folder schemas

Folder schemas

Photon Ledger's scanner recognises two folder layouts out of the box. It does not rely on these — every classification (target, filter, frame type, session date) is sourced from the FITS header. The folder layout is used only as a fallback and to inform per-folder progress UI.

Date-first

archive/
├── 2024-08-13/
│   ├── Light/
│   │   ├── M81/        *.fit
│   │   └── M82/        *.fit
│   ├── Flat/           *.fit
│   ├── Dark/           *.fit
│   └── Bias/           *.fit
└── 2024-08-14/
    └── ...

Target-first

archive/
├── M81/
│   ├── 2024-08-13/
│   │   ├── LIGHT/      *.fits
│   │   ├── FLAT/       *.fits
│   │   ├── DARK/       *.fits
│   │   └── BIAS/       *.fits
│   └── 2024-08-14/
│       └── ...
└── NGC7000/
    └── ...

What if my layout is different?

Photon Ledger still works. It will fall back to whatever the FITS header reports — OBJECT, FILTER, IMAGETYP, DATE-OBS. If your headers are well-formed, no folder structure is required at all. Per-folder progress UI may look chunky for unusual layouts; results are identical.

File extensions

Both .fit and .fits are picked up. Compressed FITS (.fits.gz, .fz) is recognised but slower to scan — headers must be decompressed.

What gets ignored

• Files smaller than 2880 bytes (no valid FITS primary HDU)
• Non-FITS files
• Hidden files (those starting with .)