I bought this base so that I could attach an ASIAIR Pro to my William Optics Zenithstar 61 II APO. The good news is it fits and does the job but with a couple of provisos.

First, do not use the screws which are included with the base, use the screws you remove from the scope instead. For this scope the given screws are too long. I suspected that when I saw them but nonetheless did cautiously try them for fit. If screwed home they will foul the focusing tube; I now have a very tiny scratch on mine as witness.

Second, the base is made for a larger diameter scope. In reality this actually doesn’t make a huge difference and it still sits securely on the tube. I thought it might rock, but it doesn’t.

Overall it’s very well made and I’m pleased with it - does what I ask of it.

I was concerned about the previous review indicating that this wasn’t compatible with the WO redcat, but it certainly does fit my original version Redcat perfectly and can now attach my Astroessentials guide scope. Just don’t overtighten as that causes the base to bow inwards which then makes it too narrow for the guide scope shoe. Comfortably done up, no problem! Thanks to FLO for the buying advice and rapid delivery.

Well made adapter for William Optical telescopes. Do note however that it doesn't fit the Redcat51 or Spacecat51.

Bought this to mount a small guide scope on my William Optics Megrez 72 scope. Although the base has provision for two fixing bolts, there's only one attachment hole on the scope. Nevertheless this seems to hold the guide scope firmly and I've had no problems with any movement when guiding.

Purchased as a red dot finder mount for my Z61. It fits adequately but is obviously made for a larger diameter 'scope. It is secure though and will only ever support the RDF so is not likely to be stressed.