The angular size of the central bright portion ( radius to first null of the Airy disk ) of the image diffracted by a circular aperture, a measure most commonly used for telescopes and cameras, is:

The diffraction pattern resulting from a uniformly-illuminated circular aperture has a bright region in the center, known as the Airy disk which together with the series of concentric bright rings around is called the Airy pattern.

The disk and rings phenomenon had been known prior to Airy ; John Herschel described the appearance of a bright star seen through a telescope under high magnification for an 1828 article on light for the Encyclopedia Metropolitana:

Light coming from a point in the object diffracts through the lens aperture such that it forms a diffraction pattern in the image which has a central spot and surrounding bright rings, separated by dark nulls ; this pattern is known as an Airy pattern, and the central bright lobe as an Airy disk.

The modern prime meridian, based at the Royal Observatory, Greenwich, was established by Sir George Airy in 1851.

A statue of Captain Burns stands on a 40 ton, Mount Airy granite pedestal in the center of the town's public square, which was given the official name of " Bailey Square " by the Yancey County Board of Commissioners on September 1, 1930.

The town of Mount Airy was founded on March 3, 1874 by Thomas Brooking of Turnerville.

Mount Airy was a popular tourist destination with many families eventually establishing homes in the area.

Griffith was born in Mount Airy, North Carolina, the only child of Carl Lee Griffith and his wife Geneva Nunn .< ref >

The Delaware Native Americans had a path through the woods from Lambertville through Mount Airy, Ringoes and Reaville to Newark upon which the Old York Road was subsequently laid.

Mount Airy was settled in the 1750s as a stagecoach stop on the road between Winston-Salem and Galax, Virginia.

Mount Airy was incorporated in 1885.

Actor Andy Griffith was born in Mount Airy, and the town is believed to have been the basis for Mayberry, the setting of the TV showsThe Andy Griffith Show and Mayberry RFD.

Mount Airy was the residence of Chang and Eng Bunker ( 1811 – 1874 ), Siamese Twins joined by a band of cartilage at the chest ( xiphopagus ).

Airy was established in 1830 and continued to develop throughout the decade, beginning with the construction of house settlements along Parr's Ridge.

The Mount Airy Historic District that includes the railroad station was added to the National Register of Historic Places in 1984.

On reading Le Verrier's memoir, Airy was struck by the coincidence and initiated a desperate race for English priority in discovery of the planet.

From 1773 until around 1829, Thomas Young discovered the disability of astigmatism and it was George Biddell Airy who designed glasses to correct that problem that included spherocylindrical lens.

Sir George Biddell Airy PRS KCB (; 27 July 1801 – 2 January 1892 ) was an English mathematician and astronomer, Astronomer Royal from 1835 to 1881.

Airy was born at Alnwick, one of a long line of Airys who traced their descent back to a family of the same name residing at Kentmere, in Westmorland, in the 14th century.

Airy was educated first at elementary schools in Hereford, and afterwards at Colchester Royal Grammar School.

The cause of this he did not long seek in vain ; thirteen times the mean motion of Venus is so nearly equal to eight times that of Earth that the difference amounts to only a small fraction of Earth's mean motion, and from the fact that the term depending on this difference, although very small in itself, receives in the integration of the differential equations a multiplier of about 2, 200, 000, Airy was led to infer the existence of a sensible inequality extending over 240 years ( Phil.

In June 1835 Airy was appointed Astronomer Royal in succession to John Pond, and began his long career at the national observatory which constitutes his chief title to fame.

The condition of the observatory at the time of his appointment was such that Lord Auckland, the first Lord of the Admiralty, considered that " it ought to be cleared out ," while Airy admitted that " it was in a queer state.

In 1847 an altazimuth was erected, designed by Airy to enable observations of the moon to be made not only on the meridian, but whenever it might be visible.

After completing these reductions, Airy made inquiries, before engaging in any theoretical investigation in connection with them, whether any other mathematician was pursuing the subject, and learning that Hansen had taken it in hand under the patronage of the king of Denmark, but that, owing to the death of the king and the consequent lack of funds, there was danger of his being compelled to abandon it, he applied to the admiralty on Hansen's behalf for the necessary sum.

The light is not focused to a point but forms an Airy disk having a central spot in the focal plane with radius to first null of

The Rayleigh criterion specifies that two point sources can be considered to be resolvable if the separation of the two images is at least the radius of the Airy disk, i. e. if the first minimum of one coincides with the maximum of the other.

Similar experiments were conducted by George Biddell Airy ( 1871 ) by means of a telescope filled with water, and Éleuthère Mascart ( 1872 ).

On 17 November 1834, the British amateur astronomer the Reverend Thomas John Hussey reported a conversation he had had with French astronomer Alexis Bouvard to George Biddell Airy, the British Astronomer Royal.

The old Baltimore and Ohio ( B & O ) Old Main Line crosses the southern part of the county from east to west, with former stations in Sykesville and Mount Airy.

Airy each a thriving, bustling community with industries along the river, including a chemical plant, sugar refinery, grain elevators and an oil refinery.

World's largest open faced granite quarry, near Mount Airy. There were 3, 667 households out of which 24. 3 % had children under the age of 18 living with them, 40. 6 % were married couples living together, 14. 0 % had a female householder with no husband present, and 41. 9 % were non-families.

The home of old-time music legend Tommy Jarrell and country singer Donna Fargo, Mount Airy has a long history with regional music.

), shares a corner with East Mount Airy to the south ( Stenton and Ivy Hill ), and Chestnut Hill to the southwest ( along Stenton Ave .)

Airy responded with a letter to Adams asking for some clarification.

It has been suggested that these are symptoms of Asperger syndrome which would also be consistent with the " repetitive behaviours and restricted interests " necessary to perform the Neptune calculations, in addition to his difficulties in personal interaction with Challis and Airy.

An introverted child, Airy gained popularity with his schoolmates through his great skill in the construction of peashooters.

From the age of 13, Airy stayed frequently with his uncle, Arthur Biddell at Playford, Suffolk.

In June 1846, Airy started corresponding with French astronomer Urbain Le Verrier over the latter's prediction that irregularities in the motion of Uranus were due to a so-far unobserved body.

This value, although considerably in excess of that previously found by different methods, was held by Airy, from the care and completeness with which the observations were carried out and discussed, to be " entitled to compete with the others on, at least, equal terms.

Only in 1830, with Airy established in his Cambridge position, was permission for the marriage granted.

Airy retired in 1881, living with his two married daughters at Croom's Hill near Greenwich.

Light passing through the lens interferes with itself creating a ring-shape diffraction pattern, known as the Airy pattern, if the wavefront of the transmitted light is taken to be spherical or plane over the exit aperture.