William Optics 50mm Slide-base Uniguide scope with 1.25'' Rotolock

William Optics 50mm Slide-base Uniguide scope with 1.25" Rotolock

  (6 Reviews)
✓ 2 year warranty


3x in stock shipped 1-2 working days

About this product

Model:  wo_50mm_uniguide_slide_base_gold
Part Number:  M-G50PB-WG

New William Optics 50mm f/4 Uniguide Slide-base Guide Scope.

Features a unique 1.25" RotoLock adapter, perfect for securely attaching guide cameras and other 1.25" accessories and a dovetail to slide into the carry handle being supplied with the latest William Optics (2019 onwards) telescopes.

Removing the RotoLock reveals an M48 male thread. 

Suitable for use with guide cameras fitted with a 1.25" nosepiece.  I.e. ZWO ASI120 Mini, ASI290 Mini, ASI174 Mini, Starlight Xpress Lodestars, etc. 

Can be used with the William Optics Slide-base Guide Rings.


  • High quality, 50mm fully multi coated objective
  • f/4 Focal Ratio / 200mm Focal Length
  • 5.7º Field of View
  • Superb William Optics fit and finish
  • 54mm Tube Diameter, 58mm Dew Shield Diameter
  • Weighs only 460g!

Telescope Field of View Simulator


Customer reviews

Average Rating (6 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Great Guide Scope but Awful Finish
01 July 2021  | 

Iím using this guide scope with my ASI224mc and it works beautifully, there is plenty of adjustment for back focus (with 1.25Ē nosepiece) and the construction is solid as would be expected from William Optics. What isnít good is the paint finish, where the tube meets the black dovetail the white paint hasnít been masked and has a scruffy looking blurred line instead of a sharp one. This has been mentioned in previous feedback entries here. When you unscrew the dew shield to focus there is an identical issue. Itís a real pity as the red and white finish elsewhere looks amazing. At this price point I would expect the aesthetics to be perfect, especially from a company like William Optics. I bought this 50mm guide scope to replace my existing one to get a more solid setup for piggy backing my Esprit 100ed (rather than use a ringed finder bracket) so will keep it, if there were other similar options then I would have returned it for a refund.

Rating (max 5):  
Muy Bueno
27 April 2021  | 

Gran experiencia de compra y atenciůn, producto excelente

Rating (max 5):  
Overall good but not easy to use
09 February 2021  | 

This is the third different brand 50mm guide scope I have tried, trying to find decent optical quality all over a full 1/3" ccd sensor. This is the best so far and is just acceptable, although I would say it isn't brilliant. It seems manufacturers have decided we dont need top quality for guiding, but that means plate-solving images taken with them can be less than ideal.

This scope is mechanically robust and once the camera and focus element are locked up, it is very stable. The dovetail seems to be cast as part of the tube and is very strong and stable (hence also not removable).

Achieving focus isn't easy though. The focus adjustment (on the front objective assembly) has only a couple of millimetres of travel. There is none at the back. Coarse adjustment is achieved by simply locking the camera in the draw tube at whatever depth is needed. Fortunately I already had a 1 1/4" par focal spacer ring so I could use this to 'set' the camera position and remove the camera without losing position. Otherwise this is a scope that once focussed is best left assembled. Although they recommend 'cylinder' type ccd's, my ZWOASI 120MM-S and a RaspberryPi HQ ccd both were able to focus with room to spare.

The paint finish is good, except at the edges both near the dovetail and focus adjustment. It seems poor masking was applied when they sprayed the main tube. The bad edge is exposed at the focus adjustment as soon as the lens is wound away from the end stop. Not what I expected from William Optics.

Rating (max 5):  
Excellent prodict
04 February 2021  | 

Ordered this, and being a beginner in this world not knowing what to expect, but had read great reviews on the product. I was very surprised at the great quality of the scope. Setting it up to get the camera in exactly the right place took a bit of playing round (probably more from us not knowing what we were doing) but now we know how it works it is nice and quick.

We will be using this as a guide scope but are using it for polar alignment in the southern hemisphere as it is near impossible to do otherwise and it has been amazing - we can get the mount polar aligned in a matter of minutes. Even tried photographing the moon with some nice results

As for FLO - I have been spending months firing questions back and forth about how best for my son to get into astrophography and they have been nothing but amazingly helpful. Order was place and shipped within 24 hours and arrived to New Zealand within two weeks (after being stuck in our customs for a week). Package arrived well wrapped and protected and the experience buying from FLO has just been awesome ... have already placed orders for more equipment with them - keep up the amazing work

Rating (max 5):  
Solid and well engineered
26 January 2021  | 

Works well with the ASI 120MM mini for guiding. It was with some trepidation, having read of people having issues with back focus, that I tried this combination, first in daylight and then with stars. Either the extension nosepiece supplied with the camera or the extension supplied with the scope need to be used - I'm using both to perhaps give more stability. The rotolock grips the camera well and at the other end the rotating dew cap (with lock ring) gives precise focus control. The base is permanently fixed to the scope - ultimately, I'm planning on using this in a WO saddle handle on top of an Esprit 100. But for now, this combination will be guiding my DSLR / lens combination in a side-by-side mount Ė once I get a suitable clamp for the narrow finder base; tests so far have been with this scope only (no imaging camera) directly clamped to my HEQ5.

Rating (max 5):  
Excellent product
22 September 2020  | 

Well engineered, easy to use and focus. The rotolock piece securely holds any 1.25" eyepiece or camera you may use the scope with.


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