William Optics Slide-base UniGuide 32mm Scope. Credit: William Optics

Guiding is an important part of astroimaging, allowing you to track objects in the night sky with great precision. Many guidescopes are available, with the William Optics Slide-base UniGuide 32mm Scope being a superior example. It boasts quality belied by its modest $109 MSRP, and is a worthy addition to wide-field or portable imaging rigs.

The William Optics Slide-base UniGuide 32mm Scope. Credit: Lee Pullen

Simple but effective design

The William Optics Slide-base UniGuide 32mm Scope features a 32mm lens with a 120mm focal length (f/3.75), and an overall weight of just 8.5oz (240g). This makes it particularly well-suited to wide-field astrophotography set-ups. Three colors are available: gold, space grey, and red (which matches well with ZWO-branded products).

A guidescope needs a guidecam, and attaching one to William Optics 32mm Slide-base Uniuide Scope is quite easy. An M42 thread is provided, or if your guidecam has a cylindrical 1.25” connection you can just pop it in and tighten the three thumbscrews. Some adjustment may be needed to get the correct back focus (20.1mm), but this doesn’t take too long. The ZWO ASI120MM Mini mono guidecam (MSRP $149) is one that works well with this guidescope.

The William Optics Slide-base UniGuide 32mm Scope can accept a variety of guidecams. Credit: Lee Pullen

Focusing is achieved by twisting the dew shield until an image is sharp, and then tightening a locking ring. It’s a fairly simple operation, and the locking ring mechanism ensures that the focus will hold. I focused my William Optics Slide-base UniGuide 32mm Scope almost a year ago and have never needed to adjust it since.

Image quality is acceptable for a guidescope, with sharp stars across the frame. The wide field of view is useful for finding a suitable guide star, or more than one as multi-star guiding is now standard with popular software PHD2, and ZWO’s ASIAIR PRO and Plus smart controllers.

The “slide-base” aspect is a built-in Vixen-style base ideal for attaching to the saddle handlebar used with many William Optics telescopes such as the popular RedCat series. The slide-base is also compatible with traditional finderscope brackets. The slide-base isn’t just a gimmick; it provides a rock-solid foundation for the guidescope, and allows it to be mounted close to a telescope’s optical tube assembly, reducing flex and helping keep an imaging rig balanced.

The “slide-base” is compatible with standard finderscope brackets. Credit: Lee Pullen

Excellent value

If you’re on a very tight budget, a slightly cheaper option is the ZWO Mini Guide Scope (MSRP of $99), which has similar specifications. But for an extra $10, the William Optics Slide-base UniGuide 32mm Scope is the superior choice.

Really, the only downside is that it’s not well-suited for use with long focal length imaging systems. For that, a guide scope with a longer focal length, combined with a suitable guidecam, will allow you to discern smaller movements in guide stars, affording greater guiding precision. William Optics offer a 50mm Guiding Scope (MSRP $173) that operates at 200mm, though you may be better served by an off-axis guider such as a ZWO OAG, which is a respected budget option with an MSRP of $128.

The William Optics Slide-base UniGuide 32mm Scope coupled with a ZWO ASI120MM Mini mono guidecam. Credit: Lee Pullen

Excellent build quality
Easy to use

Not suited to long focal length imaging rigs

MSRP: $109


Read more in Urban Astrophotography’s William Optics Slide-base UniGuide 32mm Scope review.


About Lee Pullen

Lee Pullen is a science writer and communicator from the city of Bristol, UK. He has a degree in Astronomy and a master's in Science Communication. He began his career writing for organisations including the Hubble European Space Agency Information Centre and the European Southern Observatory, as well as becoming Staff Writer for the International Year of Astronomy 2009, the world's largest ever science outreach initiative. Lee runs the website

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