Your first crossmatch¶

Stub. This notebook is part of the documentation scaffold. The final version will walk through a real Gaia DR3 × 2MASS crossmatch over a small sky region, with plots.

Planned flow:

1. Download a small Gaia DR3 and 2MASS subset over a ~2 deg cone using acid download --cone.
2. Open them with acid.init("./data/") and inspect schemas via acid.list_catalogs() and cat.describe().
3. Run a nearest-neighbor crossmatch at 1″ with gaia.crossmatch(twomass, radius=1*u.arcsec), look at the distance distribution, and plot a (J vs G) color-magnitude diagram with matplotlib.
4. Swap in maxmatch=-1 (every match within the radius) and how="left" (keep unmatched anchors) to see what changes.
5. Save the result with Catalog.save(name) for the queryable HATS form, or .export("matches.parquet") for a single-file dump.

See the Quickstart for the commands that get you to step 1 today.