and Mr Grosser in Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the wor ...
in the 1870s, who not only set up a telescope but also an illuminated microscope. Some sidewalk "pitch men" charged the public to view astronomical objects through their telescope but other astronomers allow people to view for free. In more recent years sidewalk astronomy has come to be more associated with altruistic
Altruism is the principle and moral practice of concern for the welfare and/or happiness of other human beings or animals, resulting in a quality of life both material and spiritual. It is a traditional virtue in many cultures and a core as ...
individuals or groups offering views of the nighttime sky as a free public educational service.["]
Because the sidewalks tend to be in light-polluted areas, sidewalk astronomers often coordinate their activities at times when brighter celestial objects like planets, the Moon, and bright stars are visible. During the day, sidewalk astronomy often includes use of a solar filter on the telescope to allow people to view the Sun. Telescopes are often larger than the average available "department store telescope", sometimes very large.
Amateur astronomical activities

With the advent and growth of organized
amateur astronomical groups, sidewalk astronomy has come to be associated with public education about astronomy via free public viewing for anyone who wishes to look through the telescope. This usually involves individual or a groups of amateur astronomers with small-to-medium-sized telescopes. Organizations such as the San Francisco Sidewalk Astronomers, founded by
John Dobson, are organized around the idea of educating people about the universe they live in by having them look through telescopes.
Dobson even promoted a design for large inexpensive
reflecting telescope
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternati ...
that he called a "Sidewalk Telescope", more commonly referred to as the
Dobsonian telescope
A Dobsonian telescope is an altazimuth-mounted Newtonian telescope design popularized by John Dobson in 1965 and credited with vastly increasing the size of telescopes available to amateur astronomers. Dobson's telescopes featured a simplified ...
.
See also
*
Amateur astronomy
Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, some amateur astronomers ...
*
Citizen science
Citizen science (CS) (similar to community science, crowd science, crowd-sourced science, civic science, participatory monitoring, or volunteer monitoring) is scientific research conducted with participation from the public (who are sometimes re ...
*
Star party
A star party is a gathering of amateur astronomers the purpose of observing objects and events in the sky. Local star parties may be one-night affairs, but larger events can last a week or longer and attract hundreds or even thousands of part ...
* ''
A Sidewalk Astronomer
''A Sidewalk Astronomer'' is a 2005 documentary film about former Vedanta monk and amateur astronomer John Dobson. The film follows Dobson to state parks, astronomy clubs, and downtown streets as he promotes awareness of astronomy through his o ...
'', a documentary about John Dobson's activities, including sidewalk astronomy
References
Smithsonian article
External links
Adventures in Street Corner Astronomy, Popular Science Mar 1921
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Amateur astronomy