Antoniadi scale
Encyclopedia
The Antoniadi scale is a system used by amateur astronomers to categorise the weather conditions when viewing the stars at night.
, he spent his time viewing Mars
from Flammarion's
observatory. He was very prestigious and was eventually given access to the Meudon Observatory, the largest of the time.
conditions and 5 being worst. The actual definitions are as follows:
I. Perfect seeing, without a quiver.
II. Slight quivering of the image with moments of calm lasting several seconds.
III. Moderate seeing with larger air tremors that blur the image.
IV. Poor seeing, constant troublesome undulations of the image.
V. Very bad seeing, hardly stable enough to allow a rough sketch to be made.
Note the scale is usually indicated by use of a Roman numeral.
Invention
The Antoniadi scale was invented by Eugène Antoniadi, a Greek astronomer, who lived from 1870 to 1944. Living most of his life in FranceFrance
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, he spent his time viewing Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
from Flammarion's
Camille Flammarion
Nicolas Camille Flammarion was a French astronomer and author. He was a prolific author of more than fifty titles, including popular science works about astronomy, several notable early science fiction novels, and several works about Spiritism and related topics. He also published the magazine...
observatory. He was very prestigious and was eventually given access to the Meudon Observatory, the largest of the time.
Current usage
Now the scale is seen as the metric system of astronomy, being used as a default measurement all over the world.What is the scale?
The scale is on a 5 point system, with one being the best seeingAstronomical seeing
Astronomical seeing refers to the blurring and twinkling of astronomical objects such as stars caused by turbulent mixing in the Earth's atmosphere varying the optical refractive index...
conditions and 5 being worst. The actual definitions are as follows:
I. Perfect seeing, without a quiver.
II. Slight quivering of the image with moments of calm lasting several seconds.
III. Moderate seeing with larger air tremors that blur the image.
IV. Poor seeing, constant troublesome undulations of the image.
V. Very bad seeing, hardly stable enough to allow a rough sketch to be made.
Note the scale is usually indicated by use of a Roman numeral.
Other ways of indicating seeing
Astronomers have devised several methods for defining the quality of seeing apart from the Antoniadi scale, including:- Transparency
- Limiting magnitudeLimiting magnitudeIn astronomy, limiting magnitude is the faintest apparent magnitude of a celestial body that is detectable or detected by a given instrument....