Inspiration for building my first binoscope came from the 2 x 22 inch made by Bruce Sayre and the 2 x 16 inch binoscope from David Moorhouse . I 'settled' for a 2 x 13 inch f/5.0 mirror system. The two almost identical mirrors were made by Mike Lockwood . Around these mirrors I built the binoscope below.
How does the binoscope behave? The optics from Mike Lockwood are very impressive! Stars for instance are pinpoint sharp throughout the entire field. The mirrors are relatively thin and therefore cool fast. Also mechanically the binoscope behaves superb, it moves very smoothly and is very stable. The 'boat' side bearings are quite large, ~100 cm in diameter. Therefore the turning point of the binoscope is relatively high. This allows comfortably viewing deepsky objects, even close to the horizon, such as in Sagittarius. Finally, it has a very good Argo Navis pointing accuracy and impeccable tracking with the ServoCAT system.
Another binoscope was made around two identical 8 inch f/6.0 mirrors made by Jan van Gastel (Jan van Gastel Mirrors). With two 8 inch mirrors this comes close to the equivalent of single 12 inch mirror. Around these mirrors I made the binoscope below, "Little", just like my youngest daughter Anna, who has a keen and encouraged interest in watching stars.
The traditional rockerbox and groundplate have been replaced by two thick rotating pieces of round multiplex. The very shallow and open mirrorbox is flanked with large 'boat' side bearings The secondary mirror cages consist of wire spiders and two sets of Crayford focussers. The images with this binoscope are very nice. The merging of the images with the long collimation rods is simple and stable.
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