An astronomer or astrophysicist is a scientist whose area of research is astronomy or astrophysics.
Astronomy is generally thought to have begun in ancient Babylon by the Persian Zoroastrian astrologer priests (the magi). Recent studies of Babylonian records have shown them to be extremely accurate for the ancient night sky. Following the Babylonians, the Egyptians also had an emphasis on ...
Astronomer Royal is a senior post in the Royal Household of the Sovereign of the United Kingdom. There are two officers, the senior being the Astronomer Royal dating from 22 June 1675, and the second the Astronomer Royal for Scotland, which dates from 1834.
King Charles II, who founded the Royal Observatory Greenwich in 1675 instructed the first Astronomer Royal John Flamsteed, "to apply himself with the most exact care and diligence to the rectifying of the tables of the motions of the heavens, and the places of the fixed stars, so as to find out the so much desired longitude ...
The Astronomical Society of the Pacific (ASP) was founded in San Francisco in 1889. It has the legal status of a nonprofit organization.
It is the largest general astronomy society in the world, with members from over 70 countries.
The society promotes astronomy education, publishing the popular astronomy magazine Mercury. It also publishes the scholarly scientific journal Publications of the Astronomical S ...
Astronomers typically use a number of different length units for different objects. The length unit used is typically determined by two criteria. The distances are closely related to the cosmic distance ladder.
the first is that the unit create manageable numbers
the second is that the unit be easily derivable from observation
Astronomical units of length - Units used for various astronomical distances.
The distances to distant galaxies are typically not quoted in distance unit ...
This short article gives you some facts and figures about the Venus Transit as well as links to other websites giving you more astronomical information.
Astronomical seeing refers to the blurring and twinkling of astronomical objects such as stars caused by the Earth's atmosphere. The astronomical seeing conditions on a given night at a given location describe how much the Earth's atmosphere perturbs the images of stars as seen through a telescope. The most common seeing measurement is the diameter (technically Full Width Half Maximum) of the seeing disc. The seeing disc diameter ("seeing") is a reference to the best possible angular resolution which can be achiev ...
The American Astronomical Society (AAS) is a US society of professional astronomers and other interested individuals, headquartered in Washington, DC. The main aim of the AAS is provide a political voice for its members and organise their lobbying.
The group was founded in 1899 by the efforts of George Ellery Hale. The constitution of the group was written by Hale, George Comstock, Edward Morley, Simon Newcomb and Edward Pickering. These men plus four others were the first Executive Council of the society, Newcomb was the first ...
The astronomical unit (AU or au or a.u. or sometimes ua) is a unit of distance, approximately equal to the mean distance between Earth and Sun. The currently accepted value of the AU is 149 597 870 691 ± 30 metres (about 150 million kilometres or 93 million miles).
The symbol "ua" is recommended by the Bureau International des Poids et Mesures [1], but in the United States and other anglophone countries the reverse usage is more common. The International Astronomical Union recommends "au" [2] and in ...
Astronomical spectroscopy is the technique of spectroscopy used in astronomy. As spectroscopy is described in its own article, this article focuses on its use in astronomy. The object of study is the spectrum of electromagnetic radiation, including visible light, which radiates from stars and other celestial objects. Spectroscopy can be used to derive many properties of distant stars and galaxies, such as their chemical composition and also their motion, via the Doppler shift.
Astronomical spectroscopy - Stars. Including:
The word transit has two meanings in astronomy:
A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at some particular vantage point.
A transit occurs when a celestial body crosses the meridian due to the Earth's rotation, about halfway between rising and setting. For instance, the Sun transits the meridian at solar noon. Observation of meridian transi ...
In ancient times, only the Sun and Moon, a few hundred stars and the most easily visible planets had names. Over the last few hundred years, the number of identified astronomical objects has risen from hundreds to over a billion, and more are discovered every year. Astronomers need to be able to assign systematic designations to unambiguously identify all of these objects, and at the same time give names to the mo ...
Astronomical symbols are symbols used to represent various celestial objects, theoretical constructs and observational events in astronomy. Many of the symbols are shared with astrology. The symbols listed here are commonly used by professional and amateur astronomers, and some are shared with astrology though there are differences depending on what part of the world you are in. (European glyphs differ slightly with American, for example)
Astronomical symbols - Miscellaneous symbols.
Astronomical year numbering is based on AD/BC / CE/BCE year numbering, but follows normal decimal integer numbering more strictly. Thus, it has a year 0 and the years before that are designated with a minus sign '−'. The era designations BC/AD are dropped. So the year 1 BC(E) is numbered 0, the year 2 BC(E) is numbered −1, and in general the year n BC(E) is numbered (1−n). The numbers of AD/CE years are not changed, but AD/CE is not used, being replaced by either no sign or a positive sign. For normal calculation a ...
An astronomical clock is a clock with special mechanisms and dials to display the relative positions of the sun, moon, zodiacal constellations, and sometimes major planets.
One of the most famous of this type of clock is the Old-Town Hall clock in Prague, Czech Republic. It is also known as the Prague Orloj. The central portion was completed in 1410. The four figures are set in motion at the hour, with Death (represented by a skeleton) striking the time. On the hour there is a presentation of statues of the Apostles at the doorways above the clock, with all twelve presented at no ...
This spelling pronunciation system is used on the planetoids and moons of the solar system pages. It's based on classical mythology glossaries such as those in Fagle's Iliad and Odyssey. It should cover the variation among English dialects more efficiently than the International Phonetic Alphabet.
Note: this transcription merges some vowel+ar sequences that are distinct in Scottish Engl ...
Sir Wilhelm Friedrich Herschel, FRS (Hanover, November 15, 1738 – August 25, 1822 Slough, then in Buckinghamshire now in Berkshire) was a German-born British astronomer and composer who became famous for discovering the planet Uranus, and made many other astronomical discoveries.
William Herschel - Biography.
As Friedrich Wilhelm Herschel in Hanover, Germany, one of ten children (of which four died very young). In 1755 the Hanoverian Guards regiment in whose band William and his brother Jacob were ...
Elongation is an astronomical term that refers to the angle between the Sun and a planet, as viewed from Earth.
When an inferior planet is visible after sunset, it is near its greatest eastern elongation. When an inferior planet is visible before sunrise, it is near its greatest western elongation. The value of the greatest elongation (west or east), for Mercury, is between 18 ...
Astronomy (Greek: αστρονομία = άστρον + νόμος, astronomia = astron + nomos, literally, "law of the stars") is the science of celestial objects and phenomena that originate outside the Earth's atmosphere, such as stars, planets, comets, galaxies, and the cosmic background radiation. It is concerned with the formation and development of the universe, the evolution and physical and chemical properties of celestial objects and the calculation of their motions. Astronomical observations are ...
(6th millennium – 7th millennium – 8th millennium – other millennia)
The 7th millennium is a period of time which will begin on January 1, 6001 and will end on December 31, 7000.
7th millennium - Astronomical events.
These are astronomical dates, so they are given in the astronomical format of Year Month Day, which allows them to be ordered.
6212 November 7: Mercury occults Regulus
6587 September 9: Venus occults Regulus
6727 August 25: Mars occults ...
