30cm Clasical Cassegrain 1970's, retrofit

The Classical Modified Cassegrain

primary focal length : 45 inches (1143mm)
backfocus : 10 inches (254mm)
Amplification (secondary) : 3.80
diameter: 11.9 inches
Focal ratio: 11.41357
Focal length : 135 inches (3438mm) Primary F ratio: 4.017857
Spacing : 31.25 inches
Secondary radius : 41.25 inches Secondary size: 3 3/4 inches (95mm)
Field curvature: 14.46429 inches
Primary correction : 100 %
Secondary correction: 200%
Airy disk size: 0.96 arc sec (diameter)
Spot size : 17x10 (RC modified) pour supprimer la coma !
Airy/spot ratio: 1.00
Degrees off Axis: 0.2 deg. (12 arc min) primary mirror
Coma free field : 24 arc min.

The Fullerscopes MK IV with the AWR motors and the FS2 controller. Goto and autoguiding works very good.

Main instrument of the Arcturus Observatory.

Fantastic optics made by Paul Jones.

Testing the new Fullerscopes MK IV mount

Before installing the new Fullerscopes mount permantly in the observatory I first wanted to test the polar alignment and the backlash of the mount. Therefore I made a set of test photos of M42 and the Moon using the long focal 102mm Polarex refractor.