Scope

Overview

Data Release 13 is the first data release of the fourth phase of the Sloan Digital Sky Survey. It includes SDSS data taken through June 25, 2015, and encompasses more than one-third of the entire celestial sphere. The coverage figures below show the sky coverage of DR13 for the eBOSS, APOGEE, and MaNGA surveys respectively.

DR13 eBOSS spectroscopic coverage in Equatorial coordinates (plot centered at RA = 8h.)
DR13 eBOSS spectroscopic coverage in Equatorial coordinates (plot centered at RA = 8h.)
A map of APOGEE plates in DR13. Plates are shown as small circles color-coded by number of visits.
DR13 APOGEE spectroscopic coverage in Galactic coordinates (plot centered at Galactic center).
DR13 MaNGA spectroscopic coverage in Equatorial coordinates.
DR13 MaNGA spectroscopic coverage in Equatorial coordinates.

With so much sky measured in so many different ways, questions about the size of the SDSS can be answered in many different ways. This page details the SDSS survey area and provides object counts in Data Release 13 in various ways.


Imaging statistics

Total unique area covered
14,555 square degrees
Total area of imaging (including overlaps)
31,637 square degrees (excluding supernova runs)
Individual image field size
1361×2048 pixels (0.0337 square degrees)
Number of individual fields
938,046 (excluding supernova runs)
Number of catalog objects
1,231,051,050
Number of unique detections
932,891,133
Median PSF FWHM, r-band
1.3 arcsec
Pixel scale
0.396 arcsec
Exposure time per band
53.9 sec
Time difference between observations of each band
71.72 sec (in riuzg order)
Global astrometric precision
0.1 arcsec rms (absolute)
Number of unique, primary sources
Total
469,053,874
Stars
260,562,744
Galaxies
208,478,448
Unknown
12,682
Effective wavelengths & magnitude limits
(95% completeness for point sources)
u
3551Å
22.0
g
4686Å
22.2
r
6165Å
22.2
i
7481Å
21.3
z
8931Å
20.5
Relative photometric
calibration accuracy (RMS)

(Padmanabhan et al. 2008)
u
1.3%
g
0.8%
r
0.8%
i
0.7%
z
0.8%

Optical spectroscopy data statistics

All programs combined

Total spectra
4,355,200
Useful spectra
4,266,444
Galaxies
2,401,952
Quasars
477,161
Stars
851,968
Sky
341,140
Unknown
200,490

Stellar (SEGUE)

Effective area (deg2)
1,317
Plates
229
Total spectra
155,520
Unique objects
138,099

Exoplanets (MARVELS)

Targets
11,040

Extragalactic (BOSS/eBOSS)

Statistic Total Unique
Spectroscopic effective area (deg2) 9,376
Plates 2,512 2,438
Spectra 2,497,484 2,269,478
All Galaxies 1,480,945 1,372,737
    CMASS 931,517 862,735
    LOWZ 368,335 343,160
All Quasars 350,793 294,512
    Main 241,516 220,377
    Main, 2.15 ≤ z ≤ 3.5 175,244 158,917
Stars 274,811 247,216
    Standard stars 52,328 42,815
Sky 238,094 223,541
Unclassified spectra 163,377 140,533

IFU spectroscopy (MaNGA)

Total galaxies
1,390
Unique galaxies
1,351
Plate scale
7 deg2
IFUs per plate
17
Wavelength
3600-10,000 Å

Infrared (APOGEE) spectroscopic data statistics

DR13 includes data for ~165,000 APOGEE targets. This includes 153,000 science targets, located in distinct types of survey fields:

~15,000 stars
in Bulge fields
~28,000 stars
in Halo fields
~55,000 stars
in Disk fields
~14,000 stars
in Kepler/CoRoT fields
~8,000 objects
in Ancillary Science fields
~1,800 stars
in Halo Stream fields
~1,200 stars
in Sagittarius dSph fields
~8,000 stars
in Star Cluster fields
~900 bright stars
observed with the NMSU 1m telescope + APOGEE, including bright standards

Exact counts are given in the table below.

Statistic Total Unique
Pointings 436
Plates 2,350 823
All stars 618,416 164,562
    with NMSU 1-m 1,185 894
Commissioning stars 46,720 11,917
Survey stars 609,554 152,645
    with S/N > 100 116,880
    with ≥ 3 visits 125,665
    with ≥ 12 visits 6,112
    Stellar parameter standards 8,481 1,214
    Radial velocity standards 269 17
    Telluric line standards 82,443 17,293
    Ancillary science program objects 34,219 11,899
    Kepler target stars 17,426 9,603