Happily Serving You in the Same Location for Over 58 Years!


Denkmeier - 99% Filter Switch Star Diagonal

Model#: FSD-99

Be the first to review this product

Availability: In stock


Manufactured by: Denkmeier Optical

Denkmeier 99% Filter Switch Star Diagonal


Denkmeier Filter Switch Star Diagonal


The Denkmeier Filter Switch is an innovative accessory for both astronomy and photography that allows the user's 2" and 1.25” filters to be moved in and out of the light path while offering full protection from dew and dust. The anodized aluminum housings of the Filter Switch, as well as the Delrin carriers and anodization and engraving processes are all proudly carried out in The USA. Denkmeier assembles each Filter Switch System in their Ocean City, Maryland facility and checks them for proper motion, fit and finish. Smooth actions and tool-free switching between filters will make your observations of the cosmos instantly more versatile and rewarding.

The Denkmeier Filter Switch can carry two filters at a time. There is a right and left filter carrier and each is marked with an “R” or an “L”. The “L” carrier cannot be installed into the right side of the Filter Switch and the “R” carrier cannot be installed into the left side. Additional two inch carriers are available by the pair only, and include a plastic storage case for each carrier for convenient storage. Any time a filter is required, it is simply slid into the Denkmeier Filter Switch where it is retained firmly enough so that it will not fall out unless the user removes it. There is enough resistance to retain the filter carrier within the Filter Switch unless the user applies enough outward pressure to pull the carrier out from the Filter Switch Housing.

Step-down adapters are available for the Denkmeier Filter Switch so that smaller diameter 1.25” format filters may be used. These are available singly and the 1.25” filters may be installed in these adapters and stored that way. The step-down adapter is installed in the 2” Filter Carrier much like a 2” filter is. Each 2” Carrier has a set-screw with a hex-head female receptacle. A small hex tool is included so that either a 2” filter or a 1.25” adapter may be installed and retained within the 2” carrier. The 1.25” step-down adapter also has a hex-screw that will retain a 1.25” filter. So, first the 1.25” filter is installed within the 1.25” step-down adapter. Then the 1.25” step-down adapter that now holds the 1.25” filter is installed within the 2” carrier. The carrier may then be loaded into the Filter Switch Housing. “R” carrier is loaded into the Right Side and “L” carrier is loaded into the left side of the Filter Switch Housing.



The Denkmeier 2" Filter Switch Star Diagonal has been designed for all telescopes capable of using a standard 2” star diagonal, including SCTs, Maksutov-Cassegrains, and classical Cassegrains. When used with refractors, an additional 5/8 inch of in-travel will be required due to the thickness of the Filter Switch housing.

This version of the Denkmeier 2" Filter Switch Star Diagonal sports a 97% Silver-Enhanced reflective mirror, and includes a Filter Switch with a right and left 2” carrier, a 2" to 1.25" eyepiece adapter, and compression rings on both the 2" & 1.25" eyepiece holders for scratch-free eyepiece retention.

Image shows engraved caps and plugs, which are optional.









Additional Information

Name Denkmeier - 99% Filter Switch Star Diagonal
Manufacturer Denkmeier Optical
Model FSD-99