Back in 2003 Hong Kong amateur astronomers were all smiles after successfully hosting the city's first Hong Kong Sidewalk Astronomy Event at a busy tourist shopping center overlooking Victoria Harbor. Hong Kong amateurs brought four dozen telescopes and binoculars for the event, including the homemade 16-inch f/4.5 Dobsonian reflector here. Clear skies afforded crowds of people their first telescopic views of the Moon and Mars.

On a muggy Saturday night, Tom Foster stood in the parking lot of Annie's Frozen Custard looking up. "I think Venus is behind the building," he said, "and isn't that Saturn on Leo's nose?" Neither devouring frozen treats nor seeking stars is an uncommon event in the life of this amateur astronomer. On this particular occasion, however, Foster was combining his two favorite passions for a purpose: He was scoping out a location for the first-ever International Sidewalk Astronomy Night. Along with amateur and professional astronomers the world over, Foster will be sharing his telescope with anyone interested in viewing a planet or star on the evening of Saturday, May 19th.

This event is organized by the San Francisco "Sidewalk Astronomers," a group founded by John Dobson in 1968. According to ISAN organizer Donna Smith, what began as a few simple emails among friends just three months ago has mushroomed into the ambitious goal of getting 1,000 scopes out on the streets worldwide. On the effort's website, Smith urges observers to set up "anywhere there are crowds of people, from San Francisco, to Sao Paulo, to Kharkov."

Word of the grassroots event spread quickly, and more than 250 teams — from every continent except Antarctica — have registered to participate. Amateurs have promised to bring the planets to the people from Iraq's Kurdistan region, to Rabat, Morocco, to Santiago, Chile, to Edwardsville, Illinois. To reach ISAN's goal of 1,000 scopes, more volunteers are still needed.

Interested in helping? To participate, just set up your telescope on May 19th in a public setting, and show passersby the Moon, planets, and stars through your eyepiece. Afterward, be sure to visit the results section of the ISAN website to record the size and name of your group, where you observed, the number of scopes, and how many people got a chance to look through an eyepiece. These numbers will help the organizers know if they met their goal, and their interactive global map of participants will show you the planetary impact of this global public astronomy night.

May 19th wasn't selected by accident. On that night the twins of Gemini will appear to stand above the western horizon for Northern Hemisphere observers, and the Moon and Venus — just 2° apart — will adorn the waist of Gemini's western twin Castor. Saturn gives the constellation Leo a bright beige nose all night long, and Jupiter will appear late and stay low in the southern sky for those in mid- to high-northern latitudes.

Helpful Resources from

Looking west-northwest in twilight

Sky & Telescope diagram

You'll find plenty of ideas for what to show people right here. For example, Alan M. MacRobert's This Week's Sky at a Glance is a wonderful resource. The same is true for Kelly Beatty's monthly podcast. And if you need a quick map of the stars for your area, please access our Interactive Sky Chart. (Note: There is a documented bug with the chart right now. To make sure the chart always displays the correct time of day, simply make your viewing location your default location.) recently added a major section, "Let's Go Stargazing!", with dozens of articles for beginning stargazers. And if you're planning to participate on May 19th, feel free to distribute our "Let's Go Stargazing brochure" (PDF).

The evening sky on May 19th promises to bring everyone involved a planetary delight. Bring it to the streets with a telescope, and the public will thank you. Don't forget to ask local businesses before you invade their parking lots. And, if you are combining custard with Questars, don't forget the napkins.


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