SDSS Science Archive Server (SAS)
The SAS is a hierarchical directory structure with named data products, and can be navigated directly:
- hierarchically by directory,
- by named data product,
- including the datamodel documentation.
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 interested in the incremental volume or the cumulative volume depends on whether you want to maintain the archive’s directory structure including the links, or if you prefer to expand the data volume by traversing the links. Although it is recommended to do so, copying the incremental volume may risk broken links unless you also copy the data from the previous releases, whereas traversing links to copy the full cumulative volume may risk obtaining duplicate files.
SDSS Access is the recommended python package to transfer each species of file within a data product, and copies the increments for each specified release keeping links intact without duplication.
In addition, SciServer Compute provides Jupyter notebooks in Python or R. You can create a SciServer account and create containers for your notebooks, as described here.
Incremental Data Volume for Data Release 20
Incremental volume for DR20:
- 258,854 directories
- 131,594,049 files
- 102.75 TB
Previous releases have a combined incremental volume:
- 5,554,702 directories
- 395,204,551 files
- 755.90 TB
Spectroscopic Pipeline Output
| Data Product | SAS Directory | Dir Count | File Count | Size |
| ALLSPEC | spectro/allspec | 2 | 4 | 3.58 GB |
| BOSS_SPECTRO_REDUX | spectro/boss/redux | 200,955 | 88,040,464 | 58.48 TB |
| LVM_SPECTRO_ANALYSIS | spectro/lvm/analysis | 517 | 347 | 144.6 GB |
| LVM_SPECTRO_REDUX | spectro/lvm/redux | 347 | 171 | 86.5 GB |
| MWM_ASTRA | spectro/astra | 49,925 | 4,064,764 | 834.8 GB |
Raw Observatory Data
| Data Product | SAS Directory | Dir Count | File Count | Size |
| BOSS_SPECTRO_DATA_N | data/boss/spectro/apo | 483 | 44,794 | 653.8 GB |
| BOSS_SPECTRO_DATA_S | data/boss/spectro/lco | 853 | 93,376 | 1.46 TB |
| FCAM_DATA_N | data/fcam/apo | 488 | 113,342 | 1.49 TB |
| FCAM_DATA_S | data/fcam/lco | 799 | 141,012 | 1.94 TB |
| GCAM_DATA_N | data/gcam/apo | 1587 | 12,682,701 | 12.50 TB |
| GCAM_DATA_S | data/gcam/lco | 2816 | 26,374,132 | 24.00 TB |
Target Data
| Data Product | SAS Directory | Dir Count | File Count | Size |
| MOS_TARGET_DIR | mos/target | 6 | 2,760 | 108.5 GB |
VAC Data
| Data Product | SAS Directory | Dir Count | File Count | Size |
| BHM_BLAZAR | vac/bhm/blazar | 2 | 2 | 170.0 kB |
| BHM_QSO_HOST | vac/bhm/qso-host | 2 | 2 | 1.100 MB |
| BHM_QSOPROP | vac/bhm/qso-properties | 2 | 2 | 952.6 MB |
| BHM_VI | vac/bhm/visual-inspect | 2 | 2 | 29.39 MB |
| BOSS_OCCAM | vac/mwm/boss-occam | 1 | 3 | 653.9 kB |
| DL1_SDSS_EROSITA | vac/mos/DL1_SDSS_eROSITA | 3 | 2 | 310.9 MB |
| MWM_ISM | vac/mwm/ism | 2 | 2 | 87.90 MB |
| MWM_MDWARF | vac/mwm/m-dwarf | 2 | 2 | 29.59 GB |
| MWM_MINESWEEPER | vac/mwm/minesweeper | 2 | 1 | 76.23 MB |
| MWM_ORBITS | vac/mwm/orbits | 1 | 1 | 524.4 MB |
| MWM_RGB | vac/mwm/rgb | 2 | 3 | 18.69 GB |
| MWM_STELLAR_AGE | vac/mwm/stellar-age | 2 | 2 | 656.71 KB |
| MWM_STELLAR_PARAMS | vac/mwm/stellar-params | 2 | 4 | 27.53 GB |
| MWM_WHITEDWARF | vac/mwm/white-dwarf | 2 | 2 | 1.869 MB |
| MWM_YSO | vac/mwm/yso | 2 | 2 | 8.89 MB |
| SPIDERS_AGN | vac/spiders/agn | 2 | 2 | 167.2 MB |
Data volumes for earlier data releases, such as: