Searching for SDSS Data using the MAST Portal
SDSS observations are available from the MAST Portal, a web-based interface for searching and downloading all data at MAST. You can search for SDSS observations using the Portal Advanced Search. All SDSS observations can be found by searching for "Mission = SDSS", or filtered by survey using the Provenance Name field (for example: "Provenance Name = MaNGA" or "Provenance Name = eBOSS") . This example query link returns all search results for the SDSS-MaNGA survey, as shown in the Figure 1 below. You can also search for a target name ("M101") or by coordinates ("14h03m12.6s +54d20m56.7s") to search for specific targets by performing a Basic Cone Search.
For most SDSS data, one row in the search results corresponds to one target (i.e., one galaxy in MaNGA or one star for APOGEE). All images, spectra, preview files, and other files pertaining to that target are contained within that row, and will be visible when a user adds a target to the Portal Download Basket.
Figure 1 - A Portal search result for all SDSS MaNGA observations. See Refining Results with Filters to learn how to filter search results.
Searching for Individual Targets or Fields
To search for individual targets, users can perform a Basic Cone Search using astronomical coordinates "RA" and "Dec" (for example "14h03m12.6s +54d20m56.7s") or by using the target name ("M101"). The "radius" parameter defines the radius of the search and can be set manually using "r=[number][unit]"M101 r=1m" will perform a cone search around M101 with a radius of 1 arc minute. The default radius depends on the size of the object but is usually 0.2 degrees for most targets.
By using a Portal Advanced Search, a user can refine their query and search for specific targets or fields in SDSS data. The Observation ID or Target Name filters are particularly useful for this. Table 1 dislpayed below shows a a summary of the observation ID patterns and target names used for each survey, to help refine your queries:
| Survey | Observation ID pattern | Target Name | Read More | Example Observation ID |
|---|---|---|---|---|
| APOGEE | sdss_apogee_[TELESCOPE]_[FIELD NAME]_[TARGET NAME] | SDSS-defined APOGEEID (typically 2MASS ID) | APOGEE Data Products | sdss_apogee_apo25m_n7789_2m23593133+5738262 |
| MaNGA | sdss_manga_[PLATE]-[IFUDESIGN] | SDSS-defined MANGAID | MaNGA Data Products | sdss_manga_9514-12704 |
| eBOSS | sdss_eboss_[PLATEID]-[MJD]-[FIBER4] | eBOSS [PLATEID]-[MJD]-[FIBER4] | eBOSS Data Products | sdss_eboss_12547-58928-0001 |
Table 1 - A summary of the Observation ID and Target Name patterns used by each SDSS survey available at MAST to help refine search queries.
For example, to search for specific APOGEE observations by field or star name (APOGEE ID), use the Observation ID or Target Name fields in a Portal Advanced Search. The target names typically are the 2MASS ID for each APOGEE observation: so searching for Target name "2M23580646+5742417" will return the APOGEE observations for that star. Note that the Portal Advanced Search also supports wildcard searches: searching for Observation ID "sdss_apogee_*lmc*" to return all observations from the "LMC" fields near the Large Magellanic Cloud.
Refer to MAST Pro Tips: Searching for Named Sources for more tips on how to perform a cone search using the target name. For APOGEE targets, spelling out "2MASS" in the target name may help resolve the targets when using an Object Name search. For example, searching for "2MASS 23580646+5742417" will return results, but using the APOGEE ID "2M23580646+5742417" will not.
MAST Portal Download Basket
Adding an SDSS observation to the Portal Download Basket will add all the data products for that observation for download. See the table above, or the relevant "Data Products" page (MaNGA Data Products, APOGEE Data Products, or eBOSS Data Products) for more details on the available products available at MAST. By default, the minimum recommended products (MRP) for download include only a subset of the files available for that target. Unchecking the MRP box will add all the remaining data products, which often includes preview files, individual visit spectra, and catalog files. Users can also select individual files to download using the check boxes in the download manager. Figure 2 shows a screenshot of the download basket for an example MaNGA observation, with the "Minimum Recommended Products" box checked, showing the four MRP files for this galaxy.
Figure 2 - A screenshot of an example download basket showing the Minimum Recommended Products (MRP) for MaNGA. Users can read product descriptions and some other information in the "details" panel on the right, filter by certain product categories on the left "Filters" panel, and select which files to download using the middle panel.
Downloading Catalog Files
Catalog files, such as the MaNGA "DRPALL" file, the APOGEE "allStar" file, or the eBOSS "spALL" file, are linked to the individual observations and will show up automatically in the download basket with "Minimum Recommended Products" filter is unchecked. An example of this for APOGEE data is shown in Figure 3 below.
Figure 3 - A screenshot of the complete set of data products for APOGEE, including the catalog files. By unchecking the "Minimum Recommended Products" filter, the SDSS catalog files will automatically appear in the download basket for any relevant observation.