A remarkable new apochromatic telescope objective designDavid ShaferDavid Shafer Optical Designshaferlens@sbcglobal.netHuman Eye Relative Sensitivity To ColorHuman Spectral Sensitivity Curves1.210090532nm0.8-Day Vision-Night Vision600.250040300350400450500550600650700750800Wavelength of Light(nm)30473nm20535nmFor a primarily visual use telescope the457nm540nm445nm10useful spectrum based on eye sensitivity is405nm40050060000completely covered by the .4358u toCOLOR WAVELENGTH (nm).7065u spectral lines.But most of thesensitivity is between .4861u and .6563u.Daytime eye sensitivityFor dark adapted night vision you lose thered end but pick up a little bit in the.4047uto .4358u range.There is not much pointin worrying about anything below .4358uApochromatic Lens (APO)To get good image quality over a broadspectrum it is necessary to bring threeor more widely separated wavelengthsto the same focus,shown exaggeratedhere.In addition it is necessary tocorrect chromatic variation of sphericalaberration (spherochromatism).140mm f/7.5 APO TRIPLET NPNALL-SPHERICALASPHERIZEDLONGITUDINALMuch has been written about these types of0.5degSPHERICALnm■0.06162r■706ABER.0.5deg■0.0559design.They may consist of either■0.03263C■656■0.009594e■546■0.03037■0.05075F■486■0.002253positive/negative/positive lens configurations■0,1048g■436■0.03615■0.09287or negative/positive/negative ones,and be airON-AXISspaced or oil spaced.It is necessary to use atON-AXIS0.40.4least one glass type with anomalous dispersion.RADIUSTHICKNESSGLASSSRFRADIUSTHICKNESSGLASSCCFor fast speeds three lenses are needed toAIR3.8176e+19AIRAST450.00000012.0000000_5-814ST443.00000012.0000000_5-816-0.1100299.0000000.100000O_NSL36299.0000000.100000O_NSL36reduce the lens powers,tolerance sensitivities,299.00000021.0000000_5-FPL533299.00000021.0000000_5-FPL53-299.0000000.1000000_N5L36-299.0000000.1000005-299.00000012.000000O_FSL35=299.00000012.0000000.4000and higher-order aberrations.1.0000e+03AIR-1.9330e+031.0000e+03AIR25.426218IMS-388.00000024.602210