TS-Optics MONORAIL 2" Refractor Focuser - Dual Speed - for 96 mm Flange

This focuser is more stable and more accurate than usual Crayford focusers. We recommend the focuser especially for astrophotography.

♦ Telescope connection: 96 mm flange with three radial M4 thread bores

♦ 360° rotation

♦ Eyepiece side connection: 2" and 1.25" receptacle with compression ring

♦ Minimal height to flange: 91 mm

♦ Draw tube travel: 50 mm

♦ Dual speed 1:10 for accurate focusing

♦ Bearing via stainless steel rail - absolutely free from twisting

♦ Central locking of the draw tube, guaranteed without tilting




 

TS-Optics 2" MONORAIL Focuser with 96 mm Flange

The TS Monorail focuser for many refractors from Skywatcher, Celestron and Orion is an improvement of the time-tested Crayford focusers. Our goal was to offer a focuser for highest loads, like heavy CCD cameras, with very high precision at the same time. We exactly succeeded in this with the Monorail focusers.

The MonorailR96 has a 96 mm connecting flange on the telescope side with three M4 internal threads and a 360° rotation. This allows the connection to ED refractors from Skywatcher and Orion with an aperture of 80 mm or more as well as achromatic Skywatcher, Celestron and Orion refractors with an aperture of 102 mm or more.
 

Attaching a viewfinder shoe

The grub screws marked on the third picture above can be removed and one or two finder shoe(s) can be attached with one M4 screw each. Make sure that the screw used does not reach deeper into the focuser than the grub screw! Otherwise, the focuser may be damaged.
 

The advantages of the TS Monorail focusers at a glance:

♦ higher load capacity than with normal Crayford focusers - instead of small ball bearings, a massive stainless steel rail, which is laterally clamped, is used.
♦ more precise guiding of the draw tube and no more tilting when locking
♦ smooth motion and finest 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 and the advantage compared with Crayford focusers:

Instead of small ball bearings, like in Crayford focusers, a massive stainless steel rail handles bearing and also lateral fixing.

The disadvantage of Crayford focusers with ball bearings: The small ball bearings of the Crayford focuser are loaded if locked. As the locking screw is not placed exactly between the ball bearings, one pair of the bearings is more heavily loaded. This results in tilting and unsharp stars in one corner.

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.

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.

 

Telescope connection:	Flange, 96 mm diameter with three radial M4 thread bores
Eyepiece side connection:	2" receptacle with compression ring and reduction adapter to 1.25"
Minimum height from telescope flange to 2" receptacle:	94 mm
Draw tube travel:	50 mm
Scale:	mmm and inch
Dual speed:	included
Bearing:	Stainless steel rail - Monorail principle
Rotation:	360° (continous)
Weight:	860 g incl. 1.25" reduction adapter

In the box:
♦ 2" Monorail focuser with 86 mm flange
♦ Reduction adapter from 2" to 1.25"