The Antoniadi scale is a system used by amateur astronomers to categorise the weather conditions when viewing the stars at night. [1]
The Antoniadi scale was invented by Eugène Antoniadi, a Greek astronomer, who lived from 1870 to 1944. Living most of his life in France, he spent his time viewing Mars from Camille Flammarion's observatory. He was very prestigious and was eventually given access to the Meudon Observatory, the largest of the time.
Now the scale considered as the metric system of astronomical seeing, being used as a default measurement all over the world. Until recently in 2018, astronomers have been debating whether a new system with more categories is necessary.
The scale is a five-point system, with 1 being the best seeing conditions and 5 being the worst. The actual definitions are as follows:
Note that the scale is usually indicated by use of a Roman numeral or an ordinary number. [2]
Astronomers have devised several methods for defining the quality of seeing apart from the Antoniadi scale, including:
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 make contributions in doing citizen science, such as by monitoring variable stars, double stars, sunspots, or occultations of stars by the Moon or asteroids, or by discovering transient astronomical events, such as comets, galactic novae or supernovae in other galaxies.
Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way.
The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory located on Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oʼodham Nation, 88 kilometers (55 mi) west-southwest of Tucson, Arizona. With more than twenty optical and two radio telescopes, it is one of the largest gatherings of astronomical instruments in the Earth's northern hemisphere.
The Royal Observatory, Greenwich is an observatory situated on a hill in Greenwich Park in south east London, overlooking the River Thames to the north. It played a major role in the history of astronomy and navigation, and because the Prime Meridian passes through it, it gave its name to Greenwich Mean Time, the precursor to today's Coordinated Universal Time (UTC). The ROG has the IAU observatory code of 000, the first in the list. ROG, the National Maritime Museum, the Queen's House and the clipper ship Cutty Sark are collectively designated Royal Museums Greenwich.
Astrophotography, also known as astronomical imaging, is the photography or imaging of astronomical objects, celestial events, or areas of the night sky. The first photograph of an astronomical object was taken in 1840, but it was not until the late 19th century that advances in technology allowed for detailed stellar photography. Besides being able to record the details of extended objects such as the Moon, Sun, and planets, modern astrophotography has the ability to image objects invisible to the human eye such as dim stars, nebulae, and galaxies. This is accomplished through long time exposure as both film and digital cameras can accumulate and sum photons over long periods of time.
The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental research organisation made up of 16 member states for ground-based astronomy. Created in 1962, ESO has provided astronomers with state-of-the-art research facilities and access to the southern sky. The organisation employs over 750 staff members and receives annual member state contributions of approximately €162 million. Its observatories are located in northern Chile.
The United Kingdom Infra-Red Telescope (UKIRT) is a 3.8 metre (150 inch) infrared reflecting telescope, the second largest dedicated infrared telescope in the world. It is located on Mauna Kea, Hawai'i as part of Mauna Kea Observatory. Until 2014 it was operated by the Joint Astronomy Centre in Hilo. It was owned by the United Kingdom Science and Technology Facilities Council. UKIRT is currently being funded by NASA and operated under scientific cooperation between Lockheed Martin Advanced Technology Center, the University of Hawaii, and the U. S. Naval Observatory. The telescope is set to be decommissioned after completion of the Thirty Meter Telescope as part of the Mauna Kea Comprehensive Management Plan.
In astronomy, seeing is the degradation of the image of an astronomical object due to turbulence in the atmosphere of Earth that may become visible as blurring, twinkling or variable distortion. The origin of this effect are rapidly changing variations of the optical refractive index along the light path of the object. Seeing is a major limitation to the angular resolution in astronomical observations with telescopes that would otherwise be limited through diffraction by the size of the telescope aperture. Today, many large scientific ground-based optical telescopes include adaptive optics to overcome seeing.
Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observatory is granted to Caltech and its research partners, which include the Jet Propulsion Laboratory (JPL), Yale University, and the National Optical Observatories of China.
Observational astronomy is a division of astronomy that is concerned with recording data about the observable universe, in contrast with theoretical astronomy, which is mainly concerned with calculating the measurable implications of physical models. It is the practice and study of observing celestial objects with the use of telescopes and other astronomical instruments.
The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes provide almost complete coverage of both the northern and southern skies. They are currently among the largest and most advanced optical/infrared telescopes available to astronomers. (See List of largest optical reflecting telescopes).
The National Optical Astronomy Observatory (NOAO) was the United States national observatory for ground-based nighttime ultraviolet-optical-infrared (OUVIR) astronomy. The National Science Foundation (NSF) funded NOAO to provide forefront astronomical research facilities for US astronomers. Professional astronomers from any country in the world could apply to use the telescopes operated by NOAO under the NSF's "open skies" policy.
Eugène Michel Antoniadi was a Greek-French astronomer.
In astronomy, limiting magnitude is the faintest apparent magnitude of a celestial body that is detectable or detected by a given instrument.
Visible-light astronomy encompasses a wide variety of observations via telescopes that are sensitive in the range of visible light. Visible-light astronomy is part of optical astronomy, and differs from astronomies based on invisible types of light in the electromagnetic radiation spectrum, such as radio waves, infrared waves, ultraviolet waves, X-ray waves and gamma-ray waves. Visible light ranges from 380 to 750 nanometers in wavelength.
Pillars of Creation is a photograph taken by the Hubble Space Telescope of elephant trunks of interstellar gas and dust in the Eagle Nebula, in the Serpens constellation, some 6,500–7,000 light-years from Earth. These elephant trunks had been discovered by John Charles Duncan in 1920 on a plate made with the Mount Wilson Observatory 60-inch telescope. They are named so because the gas and dust are in the process of creating new stars, while also being eroded by the light from nearby stars that have recently formed. Taken on April 1, 1995, it was named one of the top ten photographs from Hubble by Space.com. The astronomers responsible for the photo were Jeff Hester and Paul Scowen from Arizona State University. The region was rephotographed by ESA's Herschel Space Observatory in 2011, again by Hubble in 2014 with a newer camera, and the James Webb Space Telescope in 2022.
Mills Observatory is the first purpose-built public astronomical observatory in the UK, located in Dundee, Scotland. Built in 1935, the observatory is classically styled in sandstone and has a distinctive 7 m dome, which houses a Victorian refracting telescope, a small planetarium, and display areas. The dome is one of two made from papier-mâché to survive in the UK, the other being at the Godlee Observatory.
The history of Mars observation is about the recorded history of observation of the planet Mars. Some of the early records of Mars' observation date back to the era of the ancient Egyptian astronomers in the 2nd millennium BCE. Chinese records about the motions of Mars appeared before the founding of the Zhou dynasty. Detailed observations of the position of Mars were made by Babylonian astronomers who developed arithmetic techniques to predict the future position of the planet. The ancient Greek philosophers and Hellenistic astronomers developed a geocentric model to explain the planet's motions. Measurements of Mars' angular diameter can be found in ancient Greek and Indian texts. In the 16th century, Nicolaus Copernicus proposed a heliocentric model for the Solar System in which the planets follow circular orbits about the Sun. This was revised by Johannes Kepler, yielding an elliptic orbit for Mars that more accurately fitted the observational data.
The Killarney Provincial Park Observatory is an astronomical observatory located at the George Lake Campground of Killarney Provincial Park . The Observatory is operated by Ontario Parks and houses two observatory buildings. The original facility contains a 10" telescope with solar filter, ideal for nighttime as well as daytime viewing of the Sun. The newer facility contains a 16" fully automated telescope with a 5" refractor and is ideal for research, astrophotography and public use. The telescopes are available for Discovery programs as well as private sign-out (self-use) by interested visitors.
Meudon Great Refractor is a double telescope with lenses, in Meudon, France. It is a twin refracting telescope built in 1891, with one visual and one photographic, on a single square-tube together on an equatorial mount, inside a dome. The Refractor was built for the Meudon Observatory, and is the largest double doublet refracting telescope in Europe, but about the same size as several telescopes in this period, when this style of telescope was popular. Other large telescopes of a similar type include the James Lick telescope (91.4), Potsdam Great Refractor (80+50 cm), and the Greenwich 28 inch refractor (71.1 cm).
