Solar Observing Guide

The AAVSO Solar Observing Guide

Download Version 1.1 - October 2017 (2.2 MB)

(There are translations of this manual into French, German, Greek, Italian, Portuguese, and Spanish available below.)

The main activity of the AAVSO Solar Section is the monitoring and recording of sunspots from which the American Relative Sunspot Numbers (RA) are computed. The AAVSO Solar Observing Guide explains exactly how this can be done in a safe and effective manner. Reading this Guide is essential for anyone interested in pursuing this fun, fascinating, and useful work.

1. Introduction and purpose
2. Cautionary note
3. Methods of observing the sun
4. Equipment
5. Observation and recording guidelines and notes
6. Reporting the observations
7. Sunspot classification
8. Resources

A - Seeing conditions
B - Zurich classification system
C - McIintosh classification system
D - Orientation and finding the equator of the sun

Primary authors:
    Frank Dempsey
    Raffaello Braga
    Rodney Howe, Solar Section Chair
    Dr. Kristine Larsen
    Dr. B. Ralph Chou (for recommendations regarding safe solar observing)
    Tom Fleming (for information included in the appendicies)

Cautionary note - PLEASE READ

The consequence of direct viewing of the image of the sun through an unfiltered telescope,
even just briefly, is potential loss of vision in the eye.

Observing the sun, especially with a telescope, is a dangerous activity that demands strict adherence to safety protocols. The sun is unique among the objects that AAVSO observers pursue because it is so bright. The most important guideline for solar observing is observe safely. This cannot be stressed enough, and if you are uncertain about any of the equipment and safety recommendations described in this Guide, please request assistance before making any observations of the Sun with your equipment.

Translations available:

  • French - (Version 1.1) translated by Bernard Candela (November 2017)
  • German - (Version 1.1) translated by Ilka Petermann (December 2017)
  • Greek - (Version 1.1) translated by Georgios Lekkas (March 2021)
  • Italian - (Version 1.1) translated by Raffaello Braga (March 2018)
  • Portuguese - (Version 1.1) translated by Alexandre Amorim (March 2018)
  • Spanish - (Version 1.1) translated by Sebastián Otero (February 2018)