Astronomy Day

Astronomy Day
Status	Active
Genre	Astronomy-related events and competitions
Date(s)	Saturday between mid-April and mid-May on or just before the first quarter moon
Frequency	Bi-annually
Country	United States
Participants	Astronomers and astronomy enthusiasts

Astronomy Day is an annual event in the United States intended to provide a means of interaction between the general public and various astronomy enthusiasts, groups and professionals.

History

This event was started in 1973 by Doug Berger, the president of the Astronomical Association of Northern California. His intent was to set up various telescopes in busy urban locations so that passersby could enjoys views of the heavens. Since then the event has expanded and is now sponsored by a number of organizations associated with astronomy.

Astronomy Day also forms part of National Astronomy Week, which begins on the preceding Monday.

Originally, Astronomy Day occurred on a Saturday between mid-April and mid-May, and was scheduled so as to occur at or close to the first quarter Moon. In 2007, an autumn rendition of Astronomy Day was added. It was scheduled to occur on a Saturday between mid-September and mid-October so as to be on or close to the first quarter Moon.

Events

The lunar influence on the schedule means that the events happen on a different date each year, rather than set calendar dates. The table below shows the dates for Astronomy Day:

Timeline of Astronomy Day events

Year	Season	Astronomy Day	First Quarter Moon
2005	Spring	April 16	April 16
2006	Spring	May 6	May 5
2007	Spring	April 21	April 24
2008	Spring	May 10	May 12
2009	Spring	May 2	May 1
2010	Spring	April 24	April 21
	Fall	October 16	October 14
2011	Spring	May 7	May 10
	Fall	October 1	October 3
2012	Spring	April 28	April 30
	Fall	October 20	October 21
2013	Spring	April 20	April 18
	Fall	October 13	October 11
2014	Spring	May 10	May 7
	Fall	October 4	October 1
2015	Spring	April 25	April 25

  indicates upcoming event

See also

Astronomy

• Night sky
• Sky brightness
• Amateur astronomy
• Apparent magnitude
• Sky & Telescope (S&T)
• Bortle Dark-Sky Scale

Environment

• Light pollution
• Skyglow
• Over-illumination
• Dark-sky movement
• Dark-sky preserve
• International Dark-Sky Association (IDA)

Events

• Earth Hour
• Earth Day/Earth Week
• Earth Week
• 100 Hours of Astronomy (100HA)
• National Dark-Sky Week (NDSW)
• National Astronomy Week (NAW)
• White House Astronomy Night

Biology

• Photobiology
• Scotobiology

External links

• Astronomical League information page on Astronomy Day
• Royal Astronomical Society of Canada - Astronomy Day