WSO Photograph The Wilcox Solar Observatory

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WSO Data: Mean Field Magnetograms Synoptic Charts Coronal Model Tables Other

The Wilcox Solar Observatory (WSO) began collecting daily observations of the Sun's global (or mean) magnetic field in May 1975 (1977), with the goal of understanding changes in the Sun and how those changes affect the Earth. That science is now called space weather. Since May 1976 daily low-resolution maps of the Sun's magnetic field have been made at WSO, along with observations of solar surface motions. The observatory is located in the foothills just south of the Stanford University campus.

Current research topics include space weather, the large-scale magnetic field, and the solar cycle. The observatory and staff are also associated with the Helioseismic and Magnetic Imager (HMI) project on the Solar Dynamics Observatory (SDO). HMI provides continuous real-time high-resolution solar observations of the velocity, intensity, and magnetic field from geosynchronous Earth orbit. The Solar Observatories Group previously operated the Solar Oscillations Investigation that uses the Michelson Doppler Imager (MDI) instrument on the SOHO spacecraft to observe the inside of the Sun.

More information is available concerning the Solar Observatories Group, the Hansen Experimental Physics Laboratory (HEPL), the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC, and about the Astronomy program at Stanford.

Stanford University operates WSO with funding provided by the National Science Foundation with Grant #1836370.
NASA funding for WSO ended in 2018. Historically WSO has been supported by NASA Heliophysics, the NSF, and the Office of Naval Research.
Dr. J. Todd Hoeksema serves as WSO director.

WSO Dedication Pictures of WSO, staff members and other local wildlife.

Solar Center Visit the SOLAR Center -- our award winning educational web site providing on-line activities to encourage and share the wonder of solar science exploration.

You can also learn about Space Science at Windows to the Universe or The Exploration of the Earth's Magnetosphere or about some topics in astronomy in general at From Stargazers to Starships.

When is Sunrise?

The Sky Above

** ** ** Announcements ** ** **

The Sun's polar field, particularly in the north, is weakening quickly.

We have caught up. An extended data gap in September and October 2022 delayed processing of source surface maps and the generation of some web pages with long-term plots and summaries. Source surface maps for CR 2261 - CR 2263 are interpolated.

WSO Solar Magnetic Field Observations


Synoptic Charts of the Photospheric Magnetic Field

Computed Coronal Field Maps

Numerical Data Tables

Data request forms for Computed Coronal Magnetic Field Tables

The Mean Magnetic Field of the Sun

Warning: WSO Polarization Sensitivity was reduced from 16 December 2016 to 18 May 2017.
Values of the mean field have NOT been recalibrated and are a factor of about 1.55 (updated) too small during that interval.

Other Quantities

Calibration Alert: WSO Polarization Sensitivity was reduced from 16 December 2016 to 18 May 2017. Calibration has been completed and values based on magnetogram measurements have been increased by a factor of 1.55. This includes the polar field values.

  • The computed tilt angle [Table] [.gif] [.ps] of the Heliospheric Current Sheet is related to the measured
  • Solar Polar Field Strength: table | [.gif] | [.ps] ||| North [.gif] | South [.gif] [ : References : ]
  • Zonal magnetic flux transport over nearly 4 solar cycles: [ .gif] [ [.ps] ]
  • Solar Dipole and Multipole Components
  • Sector Boundary Lists

    Calibration NOTES:
      2017: Warning: WSO Polarization Sensitivity was reduced from 16 December 2016 to 18 May 2017 due to contamination on the Littrow lens.
      Magnetograms and derivative products have been recalibrated (21 March 2018).
      Note that Meanfield values have not been recalibrated.
      2000: WSO sensitivity problems from CR 1970 - CR 1992 (November 2000 - July 2002) have been quantified and the data have been recalibrated.
      Contact us if you detect any anomalies.
      Note that Meanfield values have not been recalibrated.

  • Related Items of Interest.
  • WTRs - WSO Task Reports
  • WTRs - WSO Technical Info
  • Schematics - WSO Technical Info
    The WSO Web Page Format and data analysis processing were updated in late 2006.
    Contents do not necessarily reflect the views of the NSF.
    Please send comments to Todd Hoeksema