| These 114mm internal diameter Parallax split tube rings fit the Takahashi FS-102 and older FSQ-106, Meade 102ED APO, and 4" Unitron refractor optical tubes. They do not fit the current FSQ-106ED, which need rings #PFS106. The rings are made of die-cast aluminum and are hinged for easy telescope installation and removal. Their hinges and no-tool knobs and hardware are made of stainless steel for long life. The rings are finished in subtly-flecked dark gun metal gray paint and are felt lined.
Three 1/4"-20 thread mounting holes are drilled and tapped in the flat boss on the bottom of each ring for installing the ring on your mount or mount dovetail plate. One hole is drilled on the centerline of each ring and is flanked by two identical holes on 37mm centers. A similar hole pattern is drilled and tapped into the top boss of each ring to allow the attachment of an accessory dovetail plate or piggyback ball-head camera mount.
The 1/4"-20 center holes are used to install the rings on the narrow dovetail plate used on Celestron Advanced Series, Meade LXD-75, Vixen Great Polaris or Sphinx, and similar mounts. While these mounts can hold the weight of the optical tube, the rings, and the added weight of other basic visual accessories, be certain that the payload capacity of your mount is sufficient to hold that weight plus the weight of any additional photographic accessories you might want to add.
The center holes can also be used to mount the rings on a wide dovetail plate, such as one of the Losmandy universal dovetail plates (#DUP and #DUPS), that have a series of holes drilled along the centerline of the dovetail.
If you are buying these rings to mount your optical tube on an Astro-Physics dovetail and mount, please specify so at the time you order. The rings will be drilled at the factory with the Astro-Physics hole spacing on 3.2" centers, instead of the standard 37mm spacing pattern described above.
If desired, a pair of 1/4"-20 thread holes can be drilled on 3.5" centers for piggyback mounting of the rings on a 4" wide telescope-specific Losmandy dovetail plate (such as the #DAP67, #DC8, etc.) using two bolts or any other 4" wide dovetail that has mounting holes on 3.5" centers. Should you want this 3.5" hole spacing, or the alternative Astro-Physics 3.2" pattern described above, let us know when you order your rings. Custom drilling of holes for the Astro-Physics 3.2" spacing, Losmandy 3.5" spacing, or any other desired custom mounting hole spacing requires an additional $15 charge.
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