In addition to the primary SDSS photometry and spectroscopy, there are a few extra catalogs created by our collaborators that are distributed through the SAS. These Value-Added Catalogs (VACs) are listed below, and include catalogs that were released in earlier data releases.
Open Cluster Chemical Abundance and Mapping (OCCAM) catalog - BOSS edition
The Open Cluster Chemical Abundances and Mapping survey catalog for MWM/BOSS DR20, based on results from the BOSS-CLAM
Catalog Data
Abstract
Until now the Open Cluster Chemical Abundances and Mapping (OCCAM) survey as been solely based on infrared data from the APOGEE spectrographs (Otto et al. 2026; Myers et al. 2022; Donor et al. 2020; 2018). This OCCAM VAC is the first to use MWM data from the optical BOSS spectrographs, combining spectroscopic radial velocities and metallicities with membership probabilities from Hunt & Reffert (2024) based on Gaia DR3 (Gaia Collaboration et al. 2023) 5-D astrometry to determine membership probabilities in radial velocity and metallicity for open cluster stars. This VAC contains two tables: (1) bulk cluster parameters such as proper motions, chemical abundances ([Fe/H] and [α/M]), and orbital parameters for 111 clusters, and (2) the DR20 data used to determine membership and the bulk parameters, including membership probabilities, positional data Gaia DR3 IDs, SDSS-V IDs, kinematics and metallicities (from the BOSS-CLAM, (Medan et al., submitted). Of the 111 open clusters included in this VAC, 95 are not found in previous OCCAM VACs so we recommend using this VAC as a supplement to the previous APOGEE based OCCAM VAC from Otto et al. (2026), published in DR19. This VAC can be found at the DR19 OCCAM VAC page. There is a Python notebook tutorial available for this VAC, which you can find on GitHub here.
Catalog last modified: 2026-07-30 12:12:10