The orientation of the grains in a dried photographic emulsion

✍ Scribed by L. Silberstein

• Publisher: Elsevier Science
• Year: 1921
• Tongue: English
• Weight: 46 KB
• Volume: 191
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/s0016-0032(21)90196-0

✦ Synopsis

THE present lens is an outcome of the war-time activity of the Eastman Kodak Company in lens design and manufacture. A lens of 6 inches aperture and 48 inches focal length has been designed and constructed by the company for the aerial service, which passed the most rigid tests. The present lens is nearly identical with this, the difference being in the glass used, a lower index flint being substituted which enabled a complete simultaneous elimination of field curvature and astigmatism to be obtained over a total field of 25 °. Correction of this kind has heretofore not been secured in any type of lens, for a total field angle greater than 1o °. Thus the field of critical definition has been more than doubled in the present lens compared with the best of previous types which makes it useful for many astronomical purposes. One of these lenses has already been constructed by the Brashear Company for the Yale Observatory. The result of the test has not yet been received.