Rayleigh distance Rayleigh distance Rayleigh distance in optics is the axial distance from a radiating aperture to a point at which the path difference between the axial ray and an edge ray is λ / 4. An approximation of the Rayleigh Distance is formula_1, in which Z is the Rayleigh distance, D is the aperture of radiation, λ the wavelength. This approximation can be derived as follows. Consider a right angled triangle with sides adjacent formula_2, opposite formula_3and hypotenuse formula_4. According to Pythagorean theorem, formula_5. Rearranging, and simplifying formula_6 The constant termformula_7 can be neglected. In antenna applications, the Rayleigh distance is
The Crests & The Crests", producing a single for United Artists in 1962, two singles for Cameo Records in 1963-64, a single for APT Records in 1965, a single for Scepter Records in 1965, and three singles for the Parkway label in 1966. James Ancrum then took over the lead, recording "Guilty" in January 1962 and charting only to #123. The group went back to touring when their 1963 Selma side "Did I Remember?" flopped. A 1964 sequel to "16 Candles", "You Blew Out The Candles", also was not successful. In 1965, J.T. Carter and Mel Tillison signed with Decca Records and