April 25th is Astronomy Day, when hundreds of organizations worldwide host special family-oriented events and festivities that showcase the wonder and excitement of the night sky.

Solar Astronomy

Solar observing has become a regular fare at many Astronomy Day activities worldwide. Here attendees at the Northeast Astronomy Forum & Telescope Show (NEAF) in New York enjoy views of the Sun in hydrogen-alpha light.

One day each spring and fall, astronomy clubs, planetariums, and other groups of sky lovers band together to expose the general public to the wonders and excitement of astronomy. Officially, Astronomy Day is celebrated "to promote the forerunner of all scientific endeavors and to provide information, resources, and encouragement in all facets of astronomy." But showing that astronomy is fun is really what it's all about.

Doug Berger, former president of the Astronomical Association of Northern California, founded this annual event in 1973 as a high-profile way of drawing public attention to the science and the hobby through exhibits and activities at urban centers. Since then the celebration has mushroomed in size and scope. Hundreds of astronomy clubs, observatories, museums, colleges, and planetariums worldwide now host special family-oriented Astronomy Day events and festivities. Some organizations extend their activities over an entire week.


Astronomy Day has traditionally been celebrated between mid-April and mid-May, on the Saturday closest to the first-quarter Moon. In 2013 it falls on April 20th. (An alternate date is October 13th.) However, local organizers often host events on other dates that better suit their needs, or to accommodate a special event like an eclipse, planetary alignment, or bright comet.

Why Participate?

This event is a great way for your club to gain visibility in your community. Having the public look through telescopes and at your displays spreads interest in astronomy throughout the general public and might even attract new members to your club. It provides a platform for discussing light pollution — an issue that should concern everyone. Perhaps most important, Astronomy Day is great morale-booster for you and your fellow club members. It brings people together for a day of sharing their love of the sky with others.

If you don't belong to an astronomy club and want to find a local club or planetarium that might be hosting an Astronomy Day celebration, check out our directory of clubs, observatories, planetariums, and science museums in North America, Europe, and Australia/New

Astronomy Day Handbook

The 76-page Astronomy Day Handbook, written by David Levy for Sky and Telescope and the Astronomical league, provides many helpful tips for planning successful events.

Sky & Telescope

More Information

To assist organizations and individuals in planning Astronomy Day programs, the Astronomical League and Sky & Telescope have prepared a fact-filled Astronomy Day Handbook. Written by David H. Levy and updated by Gary Tomlinson, the 76-page guide offers time-tested suggestions for conducting large and small endeavors. It also includes the rules and entry forms for the Sky & Telescope Astronomy Day Award, prizes given annually to the groups whose programs do the best job of "Bringing Astronomy to the People."

The Astronomy Day Handbook is available for free as an 850-kilobyte Adobe PDF file.

The Astronomical League maintains the official Astronomy Day Web page, which describes the event's background and where to find an Astronomy Day activity in your area. Additional listings can be found through the Night Sky Network.

Also available for printing and handing out is our ever-popular Good Neighbor Outdoor Lighting flyer, a clear, simple info sheet on light pollution and how anyone can minimize it. It's a 164-kilobyte PDF file.


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