ToupTek Finder/Guiding Scopes with 1.25-inch Crayford/Rack-and-Pinion focuser

Two finders in four different versions:

• FS-200AC
  Ø 45/200 mm with 1.25" Crayford focuser
• FS-200AR
  Ø 45/200 mm with 1.25" rack and pinion focuser
• FS-250AC
  Ø 45/250 mm with 1.25" Crayford focuser
• FS-250AR
  Ø 45/250 mm with 1.25" rack and pinion focuser
• Backlash-free & very sensitive focusing
• Easy-grip focusing wheel
• Millimetre scale
• Telescope thread: M42x0.75 thread
• Brass clamping ring with 3 counter screws
• Vixen finder base system with M6 and large 3/8" internal photo thread
• Tube clamps with M5 threaded holes for additional accessories

These finder scopes can be used with optional accessories for visually locating celestial objects or as a small guiding scope.

Optional 1.25-inch accessories are required for visual observation, such as a zenith mirror/prism (or an optional Amici prism for a sideways/upright image) and a suitable eyepiece.

Legend

• FS stands for Finder Scope
• A stands for Achromatic Lens.
• C stands for Crayford eyepiece holder
• R stands for Rack-and-Pinion

Optics

The optics of the viewfinder telescopes consist of a 2-lens cemented achromatic lens and are multi-coated to further improve the light transmission of the lenses and prevent reflections.

The aperture is 45 mm in each case.

The focal length of the FS-200 is 200 mm with an aperture ratio of f/4.4. The focal length of the FS-250 is 250 mm with an aperture ratio of f/5.5.

Mechanics

The housing of the ToupTek viewfinder is made entirely of aluminium and CNC-milled to ensure both stability and aesthetics.

The 1.25" eyepiece extensions are available as either Crayford or rack and pinion extensions. Both versions are completely backlash-free and can be adjusted with great precision.

The focusing knob has a bevelled knurling that is both attractive and practical.

An index scale with millimetre graduations facilitates quick reproducibility for different applications, e.g. for visual or photographic use, where the focal points are usually located at different positions.

A brass clamping ring ensures that the accessory is securely fastened with three clamping screws.

The locking screws can be completely unscrewed, allowing the M42x0.75 external thread to be used, e.g. to directly adapt an optional T-2 ring for your camera or other T-2 accessories securely and without tilting.

Tip: An optional tracking camera with M42x075 internal thread can also be permanently attached, for example – the unit can then be rotated using the tube clamps. This gives you a completely tilt-free system.

Variable – or do I need to focus more on the optics?

No problem, just unscrew a tube element and everything fits again, cool, right?

Viewfinder foot – Vixen system

Thanks to the Vixen system, the viewfinder fits into most viewfinder shoes. If you are unsure, you will find the technical sketch in the photos.

It also has an M6 internal thread and a large 3/8" internal photo thread.

The tube clamps have additional M5 internal threads so that further accessories can be adapted if necessary.

The beautiful blue ToupTek anodisation rounds off the design and adds elegance to your telescope setup.

Technical Data

*without Dustcap

Scope of delivery

In addition to a cardboard box with foam insert, the scope of delivery includes a front dust cover.
No cover is supplied for the eyepiece side, as the tracking camera or eyepiece accessories usually remain mounted.

You can also order our Astrogarten 3D 1.25" dust cover plugs at the same time.

Note:

The finder scopes cannot be adjusted axially, as is the case with a conventional finder scope, for example, which you can position parallel to the optics using a crosshair eyepiece.

This is not important if you want to use these viewfinder telescopes as guide scopes, as the guiding camera uses the entire field of view and you can search for any stars using your special guiding programme: perfect!

For long focal lengths, such as those used by Schmidt-Cassegrain and similar systems, you should rather use off-axis guiders to achieve better tracking accuracy (you will notice if your long focal length images are not perfectly tracked (‘guided’).

In this case, focal length is important again.