Astro-Physics Mounting Plate Introduction
Dovetail Systems: Saddle Plates and Sliding Bars
Over the years, dovetail systems have become a mainstay in the amateur astronomy community. A dovetail system
consists of a saddle (sometimes called a receiver) plate which is attached to the declination axis of a mount, and a
dovetail sliding bar (or plate). The telescope's rings are attached to the dovetail sliding bar, and then the ring/bar
assembly is seated into the saddle plate. Slide the plate forward or back to balance your telescope and tighten the knobs
to secure it. We offer a variety of widths to accommodate juat about any large or small telescope that you may own.
This arrangement is extremely popular due to the ease of setup and the versatility it offers to those with multiple
instruments. A variety of sliding bars are now available to allow the astronomer to switch between the smallest refractor
and the largest reflector in his collection with but a few minutes of precious observing time lost.

Other pertinent applications include:••••

Aid in re-balancing your scope after switching from featherweight orthoscopics to hefty eyepieces, binocular
viewer or camera arrays
Quickly interchange accessories when used as an accessory plate in the "piggyback" position
Facilitate multi-instrument, side-by-side setups
Allow users to use scopes and various manufacturers' accessories on a given mount

Astro-Physics dovetail saddles have a unique slot design which permits the user to tilt a sliding bar into place, rather
than trying to slide it in from the end of the saddle. This latter arrangement can be an awkward task when a heavy
telescope is attached to the sliding bar! Our saddles are also designed with a U-groove safety feature on each end of thedovetail channel to help "catch" a sliding bar from slipping through if the clamps are accidentally loosened (assuming thesliding bar has the appropriate safety stop!).
Our dovetail bars include a safety screw threaded into the bottom surface of each plate to aid in the prevention of adropped instrument. We strongly recommended that you NEVER leave your telescope hanging from your saddle plate byonly this safety screw without the clamps tightened down. Serious and irreparable damage is likely to occur!
Most dovetail bars have multiple holes to attach various telescopes, but the bars differ in length and width. Similarly,
saddle plates can vary in length and channel width, and can only accommodate dovetail sliding bars that match theirgiven specifications. If you are not sure which plates would be best for your setup, please call our technical support
department for assistance.

Flat and Ribbed Plates
Flat and ribbed plates may be the connection of choice for the astronomer with a permanent installation. Situations
which might warrant your consideration of a fixed mounting system:••••

Very large instrument
Exceptionally heavy imaging or accessory load
Setup being used for critical applications
Ability to switch instruments is not a priority

These plates provide a solid connection to your mount while naturally reducing flexure potential. Astro-Physics flatplates are made of solid aluminum and are machined for the addition of keyhole slots to attach telescope rings. Ourribbed plates are thicker than our flat plates. However, a portion of the material is removed from the underside of theseplates in such a way as to provide strength without the excess weight load. We recommend these plates for the largest
instruments.

Fasteners for Plates
Mounting plates ordered from Astro-Physics come with screw packets to attach them to our mounts. For a listing of therequired fasteners for a given application, please refer to our Mounting Plate Fastener Chart PDF.