Evolution of the Astronomical Eyepiece - Brayebrook Observatory

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EVOLUTION of the ASTRONOMICAL EYEPIECE 14
EVOLUTION of the ASTRONOMICAL EYEPIECE PROPERTIES OF AN ASTRONOMICAL EYEPIECE WHEN USED IN COMBINATION WITH A TELESCOPE OBJECTIVE The magnification is given by: M = F Fe = D Ep where F is the objective effective focal length D is the objective aperture Fe is the eyepiece effective focal length Ep is the exit pupil diameter This can be increased by employing a Barlow lens, where amplification: where B is the Barlow focal length A = S d & S = B A −1 ( ) By increasing the effective focal length of the objective in this way, the focal ratio is reduced, which impr oves off axis performance and reduces residual chromatic and spherical aberrations owing to the smaller exit pupil. The useful range of exit pupil diameters lies between 8mm and 0.5mm. An exit pupil much wider than 8mm, the widest pupilliary opening, effectively stops down the objective; exit pupils smaller than 0.5mm are accompanied by unwanted dif fraction effects that significantly reduce contrast. In ter ms of objective aperture, the useful magnification range is: 2D ( mm) ≥ M ≥ 0.125D ( mm) The exit pupil is related to the objective focal ratio by: Ep = Fe f / no. and hence the upper and lower limits of the eyepiece focal length are dependent purely on the objective focal ratio: at M min Fe max = 8. f / no. at M max Fe min = 0.5.f / no. 15
Page 3 and 4: EVOLUTION of the ASTRONOMICAL EYEPI
Page 5 and 6: THE EVOLUTION of the ASTRONOMICAL E
Page 7 and 8: THE EVOLUTION of the ASTRONOMICAL E
Page 13: EVOLUTION of the ASTRONOMICAL EYEPI
Page 37 and 38: ZEISS ASTROPLANOKULAR - A 2-1-2 eye
Page 41 and 42: WHAT ARE THE BEST DESIGNS EVOLUTION
Page 43 and 44: THE EVOLUTION OF EYEPIECE DESIGN (C
Page 45 and 46: TESTING EYEPIECES EVOLUTION of the
Page 47 and 48: TESTING EYEPIECES (cont): EVOLUTION
Page 51 and 52: appendix APPARENT LUMINANCE of TELE
Page 53 and 54: appendix APPARENT LUMINANCE of TELE
Page 55: BIBLIOGRAPHY LABORATOR Y INSTRUMENT
Page 60: EVOLUTION of the ASTRONOMICAL EYEPI

Evolution of the Astronomical Eyepiece - Brayebrook Observatory

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