Obscured Airy Pattern
Similar equations can also be derived for the obscured Airy diffraction pattern which is the diffraction pattern from an annular aperture or beam, i.e. a uniform circular aperture (beam) obscured by a circular block at the center. This situation is relevant to many common reflector telescope designs that incorporate a secondary mirror, including Newtonian telescopes and Schmidt–Cassegrain telescopes.
where is the annular aperture obscuration ratio, or the ratio of the diameter of the obscuring disk and the diameter of the aperture (beam)., and x is defined as above: where is the radial distance in the focal plane from the optical axis, is the wavelength and is the f-number of the system. The fractional encircled energy (the fraction of the total energy contained within a circle of radius centered at the optical axis in the focal plane) is then given by:
For the formulas reduce to the unobscured versions above.
Read more about this topic: Airy Disk
Famous quotes containing the words obscured, airy and/or pattern:
“Politics is not an end, but a means. It is not a product, but a process. It is the art of government. Like other values it has its counterfeits. So much emphasis has been placed upon the false that the significance of the true has been obscured and politics has come to convey the meaning of crafty and cunning selfishness, instead of candid and sincere service.”
—Calvin Coolidge (18721933)
“Two children, all alone and no one by,
Holding their tattered frocks, throan airy maze
Of motion lightly threaded with nimble feet
Dance sedately; face to face they gaze,
Their eyes shining, grave with a perfect pleasure.”
—Laurence Binyon (18691943)
“Although the pattern prevailed,
The breaks were everywhere. That she could think
Of no thread capable of the necessary
Sew-work.”
—Gwendolyn Brooks (b. 1917)