STARTEST IMAGES GALLERY

 Refractor150_2

Type: Refractor Triplet (Apochromatic)
Aperture: 152mm
Focal length: 1200mm (f/8)
 

Twymann Greene Test (532nm)
0.202 PTV  0.026 RMS  Strehl 97.4 %
 

Startest Images copyright
Markus Ludes (c) 2001

Picture

Inside Focus

Inside Focus

Outside Focus

Outside Focus

“This is a triplet airspaced Super ED Apochromatic design which is fully multicoated. On todays market this represents the top of the line for 6" Apo’s. No other lens known to us comes close in terms of colorcorrection. The startest image show pure white diffraction at any power. The lenses are very smoothly polished and show an excellent spherical correction.

Markus Ludes (APM-Telescopes)

Note: these image where taken using a 10” MN as an autocollimator, therefore an artificial obstruction of 37% is visible.

Picture

This refractor again has an artificial obstruction added. The obstruction was estimated at 37% but in the simulations an obstruction of 38% seemed to be closer to reality. Probably additional vignetting also were added during the photography. The simulation was easily arranged and the small overcorrection in LSA is nicely compensated with a nearly equal amount of HSA. The total wavefront estimate therefore is very low with 0.043 PV and 0.015 RMS. Compared the the Twymann-Green interferometrical results the simulation is far to optimistic.

Cor Berrevoets