The Muscle Plate


Steve Mandel and I have designed a new cover plate for the CFW-8 that is much stronger, and has some additional features, that many of us have been looking for. We call it the "Muscle Plate" and it's a cover plate on steroids.<G> Like the Mandel Wide Field Adapter for Nikon Lenses, it simply replaces the standard CFW-8 cover and adds some very desirable features. Potential flexure of the original cover plate, which can lead to image movement, erratic filter wheel operation, and loosening of the T-thread adapter is minimized.

Muscle Plate (left) and original cover plate

The strength of the MP is apparent due to the larger size. Also, the tapped holes for mounting the AO-7 directly to the plate, with no hardware intruding into the filter wheel space is noteworthy.

Muscle Plate features:

bulletSolid mounting for any T-thread adapter via a nylon-tipped locking setscrew
bulletThe AO-7 is flush-mounted to the Muscle Plate via supplied screws, which gives an extremely secure and rigid mount for the camera to the AO-7.  The Muscle Plate is mounted to the CFW-8 housing with flush, flat head screws.
bulletAdds great strength to the CFW-8/camera combination
bulletNo modification of the CFW-8 or AO-7 is required
bulletAll mounting hardware is supplied
bulletMade of black anodized aluminum
bulletEasy installation
bulletEach unit is guaranteed to equal, or exceed, the flatness of the standard CFW-8 plate
bulletMoney back guarantee if not satisfied

Note: The Muscle Plate changes the back focus requirements.  For non-AO-7 uses, the back focus requirement is increased by 0.19"; for AO-7 use, the back focus requirement is reduced  by 0.14".  This may be significant, depending on your telescope's back focus adjustment range.


Note the increased thickness, about 4x, where the plate, and therefore either the AO-7 or any other T-thread accessory mounts. This insures the plate does not flex or move due to the off-axis load, represented by the camera, filter wheel, etc.

A setscrew, indicated by the Allen wrench on the MP, guarantees a secure mount of the T-thread adapter, while the standard plate depends only on the friction of the hand-tightened T-thread adapter.

Note how it is possible for a T-thread adapter, in this case the one from the captain's wheel of the AO-7, intrudes into the filter wheel space. Here, this is enough to interfere with filter wheel rotation.  The additional thickness of the MP prevents this from happening.

Edge comparison of Muscle Plate and original plate


The Muscle Plate retails for $125 plus shipping and is available from

Anacortes Telescope and Wild Bird
9973 Padilla Heights Road
Anacortes, WA 98221 USA
Phone: (360) 588-9000 Fax: (360) 588-9100


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