Dusk occurs at the darkest stage of twilight, or at the very end of astronomical twilight after sunset and just before nightfall. At predusk, during early...

during the stage of nautical twilight when they can distinguish a visible horizon for reference (i.e. after astronomic dawn or before astronomic dusk). Under...

The Strasbourg astronomical clock is located in the Cathédrale Notre-Dame of Strasbourg, Alsace, France. It is the third clock on that spot and dates from...

Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics...

Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate...

Engineering on an astronomical scale, or astronomical engineering, i.e., engineering involving operations with whole astronomical objects (planets, stars...

A year is the time taken for astronomical objects to complete one orbit. For example, a year on Earth is the time taken for Earth to revolve around the...

(degrees below the horizon) in the morning. These are astronomical, nautical and civil twilight. Astronomical dawn begins when the center of the Sun is 18 degrees...

typical day during polar night in Vadsø, Norway will begin with astronomical night, astronomical twilight, nautical twilight, and civil twilight in that order...

The Islamic Astronomical Bureau was a government agency of Imperial China established in 1271 during the reign of Yuan Emperor Kublai Khan. The bureau...

Space art, also known as astronomical art, is a genre that visually represents the universe through various artistic styles, or sends artworks into space...

International Council on Monuments and Sites (ICOMOS) and the International Astronomical Union (IAU). While Kak's interpretation has been included in recent overviews...

In astronomy, a transit (or astronomical transit) is the passage of a celestial body directly between a larger body and the observer. As viewed from a...

stars. Originally, the term "nebula" was used to describe any diffused astronomical object, including galaxies beyond the Milky Way. The Andromeda Galaxy...

A list of future observable astronomical events. These are by no means all events, but only the notable or rare ones. In particular, it does not include...

birds experience multiple stages of sleep visible via electroencephalography. The stages of sleep are wakefulness, three stages of non-rapid eye movement...

detection due to the limited sensitivity, and relative remoteness, of astronomical observatories and due to the sometimes overwhelming spectral absorption...

in one theoretical stage by correspondence. The languages of the Olympiad are English and Russian. Russian Open School Astronomical Olympiad by Correspondence...

Demonstration". Bulletin of the American Astronomical Society. 38. 2007 AAS/AAPT Joint Meeting, American Astronomical Society Meeting 209, id.58.06: 972. Bibcode:2006AAS...

disappearance of the Sun below the horizon of the Earth (or any other astronomical object in the Solar System) due to its rotation. As viewed from everywhere...

Spectroscopy of Symbiotic Stars. I. Orbits for Well-Known S-Type Systems". The Astronomical Journal. 119 (3): 1375. Bibcode:2000AJ....119.1375F. doi:10.1086/301260...

not an astronomical full moon, but the 14th day of a lunar month. Another difference is that the astronomical equinox is a natural astronomical phenomenon...

levels can be defined, from the highest level to the lowest: Highest astronomical tide (HAT) – The highest tide which can be predicted to occur. Note that...

The Orbiting Astronomical Observatory (OAO) satellites were a series of four American space observatories launched by NASA between 1966 and 1972, managed...

potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later...

A failed supernova is an astronomical event in time domain astronomy in which a star suddenly brightens as in the early stage of a supernova, but then...

with eccentricity is that proximity to the Sun occurs during different astronomical seasons. Milankovitch studied changes in these movements of the Earth...

Phanerozoic eonothem into internationally accepted stages using two types of benchmark. For younger stages, a Global Boundary Stratotype Section and Point...

The Infrared Astronomical Satellite (Dutch: Infrarood Astronomische Satelliet) (IRAS) was the first space telescope to perform a survey of the entire night...

astronomical object is a meteorological optical phenomenon, in which light rays are bent to produce distorted or multiple images of an astronomical object...