Major Surveys

Large Surveys and Archives at NOAO


(Jump to Imaging Data and Object Catalog Access)

NOAO hosts and operates several of the world's premier facilities for wide-field survey astronomy. International teams of researchers are using these telescopes and instruments to design and execute large-scale observing programs to map our Galaxy and universe in unprecedented detail, and to address forefront scientific questions in astrophysics and cosmology.

These surveys generate data sets that have a substantial legacy value by virtue of their size, uniformity, and quality. And, as the products of a publicly funded national observatory, these data sets also become fully public and open to all astronomers after an initial proprietary period.

These archival data sets present new scientific opportunities beyond the original survey design goals: new searches for rare objects in large samples, new scientific analyses of massive astronomical catalogs, and new combinations with other complementary data sets. Looking further to the future, the development and dissemination of new approaches to exploring and analyzing large online astronomical catalogs is essential for enabling the widest range of astronomical community science with the Large Synoptic Survey Telescope (LSST).

As the significance of large archival data sets in astronomy continues to increase, NOAO is developing new tools in the NOAO Science Archive and NOAO Data Lab to make these data sets accessible to all astronomers. 

This page describes the largest present and future surveys delivering public data sets to the NOAO archive.


Imaging Surveys


The Dark Energy Survey (DES) is a major collaboration project using the Dark Energy Camera (DECam) on the 4m Blanco Telescope at CTIO. The primary goal of DES is to constrain the nature of dark energy through observations of galaxy clusters, supernovae, large-scale structure, and weak gravitational lensing.

The DECam Legacy Survey (DECaLS) and Mosaic z-band Legacy Survey (MzLS) are using DECam on the Blanco Telescope and the Mosaic-3 camera on the 4m Mayall Telescope at KPNO to conduct wide-area surveys that will be used in combination with northerly DES data for target selection by the DESI survey (see below).

Public survey data for DESI targeting is also being delivered to the NOAO archive by the Beijing-Arizona Sky Survey (BASS) using the 90Prime camera on the 2.3m Bok Telescope operated at KPNO by the University of Arizona's Steward Observatory.

The following table gives an overview of the datasets that these surveys will deliver to the public NOAO archive. (Depths are 5-sigma point source detection thresholds.)



Observing Dates Area Bands & Depths Public Data Release Plan
DES 4m Blanco / DECam (CTIO) 2013 - 2018 5,200 deg2 g = 26.5; r = 26.0; i = 25.3; z = 24.7; Y = 23.0 Raw: 12 months proprietary. Processed frames: approx. yearly. Catalogs: mid-survey and end-of-survey
DECaLS 4m Blanco / DECam (CTIO) 2014 - 2016 6,700 deg2

g=24.7; r=23.9; z=23.0

Raw: immediate. Processed frames: as soon as available. Catalogs: every 6 months

MzLS 4m Mayall / Mosaic-3 (KPNO) 2016 - 2017 5,000 deg2 z = 23.0 Raw: immediate. Processed frames: as soon as available. Catalogs: every 6 months
BASS 2.3m Bok / 90Prime (Steward/UA/KPNO) 2016 - 2018 5,000 deg2 g = 24.0; r = 23.6 TBD


Imaging Data and Object Catalog Access


The following table describes how to obtain the latest available data products from major public imaging surveys archived by NOAO.

Data Product Survey(s) Access Method
Raw Imaging Frames All Available through the NOAO Science Archive query form after the expiration of any proprietary period.
Reduced Imaging Frames
(Instrumental Signatures Removed)
DES, DECaLS (MzLS and BASS when available) Go to the same NOAO archive page as above, and click on the appropriate "NOAO Surveys" option within the "Available Collections" panel at left.
Object Catalogs DES Science Verification (SVA1) data products, including early-release catalogs, are currently available through the DES Data Management system (DESDM) SVA1 site at NCSA.
DECaLS Data Release 2 (DR2) data products, including catalogs, can be obtained through the DR2 page of the Legacy Survey team website.
All As of mid-2017, catalogs from these and other NOAO surveys will be served through multiple high-level interfaces as part of the NOAO Data Lab project. Look for a preview of the Data Lab at the 228th meeting of the American Astronomical Society in San Diego, CA in June 2016.


Spectroscopic Surveys


Starting in 2019, the 4m Mayall Telescope at KPNO will host the Dark Energy Spectroscopic Instrument (DESI), which will be the most powerful multi-object survey spectrograph in the world. The DESI project and collaboration will conduct a spectroscopic survey to build the largest three-dimensional map of the universe. By analyzing the gravitational clustering of galaxies, quasars, and intergalactic gas clouds within this map, DESI will derive the most precise contraints on the nature of dark energy.

The database of spectra from the DESI survey will be served publicly through the NOAO archive (schedule to be determined), and will be the largest homogeneous collection of medium-resolution optical spectra obtained from a single instrument.

The following table summarizes the parameters of the DESI instrument and survey.

Telescope 4m Mayall, KPNO
Focal Plane 5,000 robotically positioned fibers over 7.5 deg2 at corrected prime focus
Spectrographs 10 spectrographs, 3 arms each, 360-980 nm, R = 2000 (blue) to 5,100 (red)
Survey Dates Commissioning 2019, 5-year survey from 2019 - 2024
Survey Area 14,000 deg2
Spectra of...

10 million bright galaxies to redshift z = 0.4, magnitude r < 19

4 million luminous red galaxies to redshift z = 1.0, magnitude r < 23

17 million emission-line galaxies to redshift z = 1.6, magnitude r < 23.4

2.5 million quasars, magnitude r < 23

10 million Milky Way stars


Last updated or reviewed February 18, 2016.