TS-Optics MONORAIL 3" Dual Speed Focuser - M117x1 thread connection

TS-Optics 3" Monorail M117 Focuser

The Monorail focuser is a further development of standard Crayford focusers. Our aim was to offer a focuser for highest loads, like heavy CCD cameras, with very high accuracy at the same time. We succeeded in exactly this with the Monorail focusers.

The TSLPR3 has an M117x1 coupling nut at the telescope side. The thread fits perfectly to RC / Ritchey-Chrétien telescopes from TS-Optics or Astro Tech from 10" aperture.

The advantages of the TS Monorail focuser at a glance:

higher load capacity than with normal Crayford focusers - instead of small ball bearings, a massive stainless steel bar is used, which is fixed at the side.

precise guidance of the drawtube and no more tilting when locked, that also allows a shorter design.

smooth running and most precise adjustment even at loads of up to 4 kg

1:10 dual speed for accurate focusing

Motor focus can be retrofitted

Operating principle of the Monorail focuser:

The advantage of the MONORAIL principle:

The function of the ball bearings is taken over by the stainless steel bar which is firmly connected to the draw tube. Nothing can bend anymore. Only lateral guidance is taken over by ball bearings. These bearings only fix the lateral position and do not need to take on load anymore. Tilting, as it is possible with conventional Crayford focusers, due to yielding of the ball bearings, is excluded here.

The drawtube is fixed with a locking screw which is exactly centered at the upper side, so the entire construction is evenly loaded. Tilting is definitively avoided, the draw tube stays exactly at the given position.

With the middle screw of the "quincunx", only the friction is adjusted - see image at left.