Astro-Tech Dovetail accessory adapter for Losmandy-style "D-plate" dovetails, black


Availability: In stock

This black-anodized Astro-Tech adapter clamps onto a Losmandy-style "D-plate" dovetail to let you mount a telescope tube ring or accessory on the dovetail . . .
Our Product #: ATDAB

Product Description

This black-anodized Astro-Tech dovetail adapter clamps onto a Losmandy-style "D-plate" dovetail plate. The adapter lets you install tube rings, photoguide rings, or other accessories on a wide Losmandy-style dovetail plate that is mounted piggyback on a larger optical tube. This lets you piggyback a second scope or photoguide scope on your main scope.

A single hand-tighten knob clamps the Astro-Tech adapter firmly in place on a Losmandy-style "D-plate" dovetail, but allows the adapter to be quickly repositioned along the dovetail so you can balance or change accessories as needed with no tools required. A three-legged lever on the knob shaft lets you apply extra pressure to clamp very heavy loads when wearing gloves or mittens. The lever also makes it easier to loosen the clamp should cold weather cause the metal to contract and the adapter to bind on the dovetail.

A series of seven unthreaded 6.9mm diameter mounting holes are drilled into the adapter in the pattern shown in the photos. The pattern and spacing of the mounting holes is shown in the engineering drawing in the feature image below. These holes allow you to use 1/4"-20 or metric bolts to mount virtually any finderscope ring, off-axis photoguide ring, ball-head camera mount, etc., on the adapter.

The holes are countersunk on the underside of the adapter so that the mounting bolts holding the accessories will not interfere with the dovetail plate. The adapter measures 4.45" wide when the clamp is fully tightened. It is 2.5" long fore and aft and 0.75" deep. The height from the top of the dovetail plate to the top of the adapter is 0.5". The adapter weighs 10.4 oz. It is hard-anodized black for long life and durability.

Tech Details

Weight 10.4 oz.
Warranty 1 year


Review by:
This AT dovetail adapter was suggested to me when asked about piggyback mounting a new AT scope. The scope gets 5 stars, but these adapters fall short. They don't have a guide pin to keep the moveable side aligned and the small secondary locking rings are awkward to use. For a few dollars more ADM, Losmandy, and others are better made and easier to use.
However, the AT brand does work and because the scope won't me moved much, the difference in ease of use was not enough to cause me to return them. An OK buy if your budget is tight, (Posted on 1/19/2024)
Review by:
It works I guess, but its a bit unwieldly manner in which to tighten. The two plate are not spring loaded, and one side of the plate can spin freely 360-deg or more. So, its a little slower in attaching to your OTA losmandy style rail. But, it should work for the purposes I intended and I got it for a substantial discount. (Posted on 8/11/2022)
Review by:
I have recently been trying some piggybacking on my primary APO, with my DSLR because I don't have a separate star tracker. I was able to fashion this into a very versatile tool by screwing on my Shoe adapter from an old Tripod, and leaving the tripod adapter permanently attached to my camera body (DSLR). Now I can quickly pop my DSLR on and off my top plate, for Piggybacking, and don't have to fidget with small screws or thumbscrews in the dark. Win Win,. (Posted on 10/4/2019)
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