This site uses all-sky catalogs and synthetic photometry
to produce photometry of stars anywhere on the sky in a set
of the most commonly-used passbands. We use cataloged observations if they exist,
and provide modeled estimates if they don't.
The goal: to provide a robust and simple way to estimate the photometric zeropoint of an astronomical image for any band in any part of the sky.
Please read the info page for a complete description, a discussion of errors, and a few examples.
Contact me with any questions!
ishivvers (at) astro (dot) berkeley (dot) edu
Enter RA and Dec (decimal degrees) and field size (arcseconds) Maximum field size is 1° (3600") per request, and large requests may take up to a minute to process.
This site can also produce matched catalogs and zeropoints of uploaded star lists - see
submission forms to the right. These both require space-separated or tab-separated
ASCII files with no blank lines (# for comments), with all coordinates in
decimal degrees. Designed for stars grouped together in a field and limited to fields
spanning 1° (3600") or less.
There is also an API, for automated queries using a program like
See here for more information.
Upload a star list with RA and Dec (decimal degrees) as the first two columns.
Upload a star list with RA and Dec (decimal degrees) as the first two columns, instrumental magnitudes as the third, and select the passband observed.