Summary APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is a pipeline for measuring stellar parameters and chemical abundances from APOGEE spectra. ASPCAP wraps the FERRE code (Allende Prieto et al. 2006), which interpolates spectra from a (potentially high dimensional) rectilinear grid and minimizes the χ2 statistic. FERRE includes options to simultaneously fit the continuum, […]
Search Results for: SDSS-IV
DR19 ApogeeNet
Summary ApogeeNet (Olney et al. 2020; Sprague et al. 2022; Sizemore et al. 2024 ) uses a convolutional neural network to estimate stellar labels (effective temperature, surface gravity, and metallicity) given a rest-frame resampled APOGEE spectrum. The network is trained on high quality APOGEE spectra and labels from SDSS-IV Data Release 17. Detailed Description ApogeeNet […]
DR19 Moving from APOGEE DR17 to DR19
Many science cases, such as chemical cartography of the Galaxy, will want to use the DR19 dataset to expand upon DR17 results, employing similar analysis. In this page, we highlight some key differences between the versions of ASPCAP in DR17 and DR19 and between the structure of the files that hold the ASPCAP data. We […]
DR19 Astra
Astra is the glue that brings together analysis methods into a single software framework. MWM observes stars across the HR diagram with both the BOSS and APOGEE spectrographs. This wide range of stellar parameters, resolution, and wavelength coverage means that a single pipeline is not currently suitable. Links on the sidebar will take you to […]
DR19 Legacy Tutorials
If you want to work with data that was released in SDSS-IV or earlier, then check the Completed Surveys page for direct links to data descriptions, caveats, and relevant tutorials. Completed surveys include: We have tutorials available on parameter files, fits files, and using bitmasks, and a page with conversions between our wavelength and magnitude […]
DR19 Bulk Data Downloads
All data can be downloaded directly from data.sdss.org or dr19.sdss.org using the wget command, but is more efficiently downloaded from the SDSS data transfer node from dtn.sdss.org using the rsync method. Access is also available via Globus Online. The Data Model page has a description of the directory structure and file formats. Note that the […]
DR19 Data Volume
SDSS Science Archive Server (SAS) The SAS is a hierarchical directory structure with named data products, and can be navigated directly: Individual data products are either replacements from previous data releases, and add incrementally to the data volume, or contain links to previous data releases, and add cumulatively to the data volume. Whether you are […]
DR19 Get Data
Spectroscopic Data There are several ways to get to the Spectroscopic Data. Below we list several ways for you to download spectra and catalogs, with the caveat that for large downloads we have additional information on the Bulk Download Page. Alternative ways to access spectra and catalogs are through: The SDSS optical spectra are split […]
DR19 Bitmasks
SDSS makes heavy use of the concept of a bitmask in spectroscopic target flags and other contexts. For the actual bit values for all SDSS flags, see the lists below. More detailed descriptions of the targeting bitmasks for the completed optical surveys and infrared surveys can be found in the DR17 release documentation. The page […]
DR19 Glossary of SDSS Terminology
This Glossary is a work in progress, and more terms will be added during the lifetime of SDSS-V. If you have come across SDSS Terminology that is not explained yet in the Glossary below, then please let us know via the SDSS Helpdesk at helpdesk@sdss.org. ABCDEFGHIJKLMNOPQRSTUVWXYZ A Adaptive Moment A method of measuring object shapes […]