Cinco de Mayo
Mother's Day in the United States is an annual holiday celebrated on the second Sunday in May. Mother's Day recognizes mothers, motherhood and maternal bonds in general, as well as the […]
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Arthur Leonard Schawlow, Nobel Prize, co-inventor of Laser, born 1921
Arthur Leonard Schawlow (May 5, 1921 – April 28, 1999) was an American physicist and co-inventor of the laser with Charles Townes. His central insight, which Townes overlooked, was the use of two mirrors as the resonant […]
Mother’s Day (USA)
Mother's Day in the United States is an annual holiday celebrated on the second Sunday in May. Mother's Day recognizes mothers, motherhood and maternal bonds in general, as well as the […]
Sir John Herschel FRS died 1871
Sir John Frederick William Herschel, 1st Baronet KH FRS (/ˈhɜːrʃəl, ˈhɛər-/; 7 March 1792 – 11 May 1871) was an English polymath, mathematician, astronomer, chemist, inventor, experimental photographer who invented the blueprint, and did botanical work. Herschel originated the use of the Julian day system in astronomy. He […]
New Moon
New Moon. By the modern definition, New Moon occurs when the Moon and Sun are at the same geocentric ecliptic longitude. The part of the Moon facing us is completely […]
Moon at Apogee
The Moon’s distance from Earth varies throughout its monthly orbit because the Moon’s orbit isn’t perfectly circular. Every month, the Moon’s eccentric orbit carries it to apogee – its most distant point from […]
Eid al-Fitr begins at sundown (Muslim)
Eid al-Fitr (/iːd əl ˈfɪtər/ eed əl FIT-ər; Arabic: عيد الفطر ʻĪd al-Fiṭr, IPA: ), also called the "Festival of Breaking the Fast" or Lesser Eid, is a religious holiday celebrated by Muslims worldwide that marks the end of the month-long dawn-to-sunset fasting of Ramadan. This […]
Astronomy Day
Astronomy Day is an international event observed each fall and spring near the first quarter Moon. Local astronomical societies, planetariums, museums, and observatories sponsor public viewing sessions, presentations, workshops, and […]
Astronomy Day
Astronomy Day is an international event observed each fall and spring near the first quarter Moon. Local astronomical societies, planetariums, museums, and observatories sponsor public viewing sessions, presentations, workshops, and other activities to increase public awareness about astronomy and our wonderful universe.
This fall, Astronomy Day will be held on October 12, 2021.
Conjunction of Mars & Moon
The planet Mars will appear in conjunction with the Moon in the western sky after sunset on this May 15, 2021.
International Day of Light
The International Day of Light is a global initiative that provides an annual focal point for the continued appreciation of light and the role it plays in science, culture and […]
Mercury at Greatest Elongation
Mercury swings to its greatest elongation east of the setting sun on May 17, 2021 (evening of May 16 for the Americas).