Brayebrook Observatory also uses a portable telescope, a 6-inch f/15 Maksutov-Cassegrain made in 1979 by the Pennsylvanian firm, Optical Techniques. It possesses very fine optics and gives exquisite images. The optics were selected 'One of One Hundred' 1/40 wave [P-V] from the Cumberland Optical Company, Philadelphia. I purchased this instrument whilst resident in Santa Monica, through Optical Technique's California dealer, Leo Henzl.
I normally use this telescope with a binocular head. Despite the 33% central obstruction it out-performs most achromatic refractors and Newtonian reflectors of similar aperture, both at low and high power. The barrel assembly employs moving primary focusing and has a large focusing knob mounted on the right hand side of the back plate, rahter than a fiddely and spindly in line focusing screw like those fitted to the Questar and Meade compact Cassegrainians.
There are two viewports; a reflex port intended for visual work, and a back plate port with a T42 fitting intended for astrophotography. The effective focal ratio is f/15 at the reflex eyeport and f/16 at the back plate. With the binoucular head fitted the effective focal ratio is increased to f/25.
For general viewing I normally use either modified Galoc or Berthele eyepieces or Koenig. For high powers I use modified Tolles made by the ATM, J.D. Greenwood.
The barrel assembly can be removed from the single-arm fork mounting, and 35mm SLR telephoto lens fitted in its place.
The tripod is a Sanders & Davis 76mm cine-camera tripod made from Berrylium-Aluminium alloy, and weighs only 9lbs. The entire telescope and mounting only weighs 35lbs.
Both barrel assembly and eyepieces/fork have separate hardwood storage cases.
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