ASI Holder Ring Dimensions

seldom

I bought a 78mm ASI holder ring, and the ring itself worked fine on my ASI1600MMC, but the space between grooves on the dovetail attachment was too small (35mm) for either of my Vixen dovetail clamps (39mm between edges) to secure it. Is the holder ring dovetail supposed to work with Vixen clamps? If not, is there a plan to provide one that does work with Vixen dovetails?

w7ay

seldom the space between grooves on the dovetail attachment was too small (35mm) for either of my Vixen dovetail clamps (39mm between edges)

I think you are referring to the Arca-Swiss quick-release dovetail plate (very popular mounting plate in photography circles). Amazon has pages and pages of the Arca plates and their mating dovetail clamps.

Just bolt the Arca plate to a Vixen or Losmany dovetail if you prefer not to use the Arca dovetail. You can also remove the Arca plate (two small M4 screws) and mount the ZWO camera ring directly to a Vixen or Losmandy dovetail plate with a 1/4"-20 bolt.

Chen

seldom

Thanks, Chen. The dovetail I am referring to is the dovetail furnished by ZWO with the ring. Can you recommend a Vixen dovetail with proper hole spacing that will mate with the two holes in the ring? Using the two M4 screws will keep the camera aligned with the mount.

w7ay

seldom Can you recommend a Vixen dovetail with proper hole spacing that will mate with the two holes in the ring? Using the two M4 screws will keep the camera aligned with the mount.

Not right offhand. But 20mm lateral screw spacing is not that uncommon in the amateur telescope world.

For example, I have a couple of PrimaLuce Losmandy plates that have 20mm spaced holes for holding the PrimaLuce tube bands, except they are M6 holes. With a couple of washers, I am sure you can mount the ZWO camera ring to a PrimaLuce plate with M4 bolts.

You have at least three other simple solutions: 1) just use Arca-Swiss to mount your camera (I use Arca-Swiss for my guide scopes), 2) bolt the ZWO Arca plate onto a Vixen or Losmandy plate with multiple screws, 3) bolt an Arca dovetail clamp to a Vixen or Losmandy plate with multiple screws, and clamp the ZWO camera to the Arca clamp.

Arca quick release clamps are quite strong; I have seen short 1"-long clamps that are spec'ed for over 20 lbs of payload (I would use a longer clamp myself :-).

Chen

w7ay

seldom The dovetail I am referring to is the dovetail furnished by ZWO with the ring.

Yes. You will find that the ZWO dovetail plate is an Arca-Swiss plate.

Chen

seldom

Thanks, Chen. I want to use the camera ring on a mount with a Vixen clamp, so I'll look for a Vixen to Arca Swiss adapter.

w7ay

seldom I want to use the camera ring

If you need to use two bolts, and are willing to spend a little bit more money, perhaps you can use two rings, much like how many people mount their OTA.

Remove the two Arca-Swiss plates, and you now have two 1/4"-20 threaded holes, one on each ring. One ring can be close to the front of the camera and the other can be towards the back of the camera.

Chen

seldom

ADM makes an Arca Swiss to "V"(ixen?) adapter that looks like it should work.