STARTEST IMAGES GALLERY
Refractor100_2

Type: Refractor Doublet
Aperture: 100mm
Focal length: 640mm (f/6.4)

startest Images copyright
Markus Ludes (c) 2001
Picture

Inside Focus

Inside Focus

Outside Focus

Outside Focus
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“This telescope is a 100/640 doublet airspaced achromat. The images show about 1/2 wave wavefront p.t.v. and 1/10 wavefront RMS in red 632 nm and about 1/3~1/4 wavefront and about 1/20 wavefront RMS in green. “

Markus Ludes (APM-telescopes)

Note: ronchi-testing with 254 lines/inch or 100 lines/cm.
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The  simulation was performed on the leftmost image (green channel). The outerrings were simulated properly but most of the inner-structure is invisible in the original image. Still the simulation managed to fit at least half of the pattern from the outeredge to the middle of the diffraction pattern in a reasonable fashion. A rather clear center-zone seems to increase the light in the original image. Zones are currently not simulated and therefore the simulation used a average path over the central zone. There seems to be a rather large amount of undercorrected LSA present and a minor amount of HSA. An estimation of the total wavefront-error is rather difficult due to the “lack of fit” of half of the diffraction pattern.

Cor Berrevoets