Incompatible dovetail bars on a mount

A while back we sold a Sky-Watcher Esprit to a client. This guy had a slightly old Sky-Watcher HEQ5 mount already, and the Esprit 100 came in under the payload for the HEQ5, so it appeared to be a good match.

When he received the telescope, the client found that the Esprit comes with the Losmandy (wide) dovetail plate that the tube rings bolt to. However, the old mount saddle only accepted the Vixen (narrow) plate.

This caused us a bit of head scratching. We considered a couple of different solutions, including an adapter (such as Orion part #07952), but that got complex.

The simplest solution I could come up with was to change the dovetail plate. The green Sky-Watcher plate is too short, and balancing a scope with a large imaging array (think a full-frame DSLR plus an off-axis guider and camera) isn't possible as you have to slide the scope a long way forward. The dovetail plate has to be longer.

Incidentally, for short focal-length refractors, this is a chronic problem. Most users find they need a new dovetail, much longer than the ones supplied.

There are a host of plates available, some with multiple holes. We talked with Alex from Sky-Watcher Australia, who recommended a plain 200mm dovetail bar (https://skywatcheraustralia.com.au/product/dovetail-bars/). We would remove the green plate from the tube rings and use a shorter bolt to connect the new dovetail to the centre hole in the five holes tapped in the top of the tube rings.

In the end, the client didn't like the idea of single bolts attaching the dovetail to the tube ring. Adept at metalwork, he drilled holes and bolted a narrow dovetail plate to the bottom of the Esprit plate. The scope sits a little high on the mount, requiring a little more counterbalancing, but otherwise it's a good solution.

As an epilogue though, the new version of the HEQ5 ships with a dual-mount saddle. This will accept both dovetail sizes, meaning an out-of-the-box Esprit will sit nicely on an out-of-the-box HEQ5.