Special Diagonals that Solve problems.

2" Diagonals

Low profile binoviewer Diagonals. Click Here

2.7" and 3" Diagonals: Click here.


Ad #1

Focusable 2" diagonals with (S)elf (C)entering eyepiece holder.

Price to convert your diagonal is $149

If we purchase and/or stock the diagonal it will cost the current cost of the brand you choose + $10 for purchase and stock costs.

Here are some diagonals you can choose from. You can click on the name to see the diagonal you are purchasing before conversion. 

If we convert your Daigonal

Converted focusable SC   WO 97% Refractor Diag $257

Converted focusable SC   WO 99% SCT  Diagonal $347

Converted focusable SC Astotech Ref Diagonal   $238

Converted focusable SC Astotech SCT Diagonal  $248


Picture soon to come


Do you have minor to "Gorilla" mirror shift in your LX series or other telescope? Are you thinking about installing a focuser after your visual back to fix the problem?  You may create more problems then you fix. Some SCT scopes have limited room between the visual back and scope fork and a focuser may make slewing to the zenith impossible.

 Or  you may not be able to come to focus with certain accessories like focal length reducers or binoviewers because of the added length of the focuser.  If nothing else the added length of the focuser will increase the magnification of your SCT by as much as 15%  

Would you like to have the problem eliminated quick and neatly without adding any more length to the back of your scope or focal length?  At the same time have your eyepiece holder a self centering type that is precise and holds your eyepiece firmly without marring the barrel. Even with the thumb screw compression ring type you really have to torque the screw down to get a good hold on the eyepiece. Not so with the feather touch self centering holder replacement sold by Siebert Optics. If we convert your diagonal the cost is $149




Ad #1C 

Please tell me your binoviewer type and how old it likely is.

Look below for instructions.

 Special low profile 1.25" diagonal for your Refractors including refractors such as WO/Astrotech 66mm/80mm ED/ Orion ED 80mm and 100mm or other refractors you might have with a 2" visual back

Price of diagonal is $169 #(Diag125)     99% transmission diagonal.

Instructions "Click here"

Look below for more pictures



This will work with the Orion ED series/WO and Astrotech and many other refractors.

What will this diagonal do when used with a Burgess/WO/Stellarvue/Orion/Celestron and other like  binoviewers including my own BN25mm.

Focus your refractors without an OCA! 

Sometimes you are so close to focus with binoviewer in your 1.25" diagonal that you can almost taste it, but can't quite get there.

Thread this diagonal in the bottom of your WO, Burgess, Celestron,Orion or Stellarvue binoviewer (Remove nose piece) and attach it to your refractor and you will be binoviewing without the added magnification of an OCA and at a price that might be less expensive then most of my OCA correctors. 


Scope in solar use and focusing nicely

Instructions below. 

Different binoviewers may need different attachment pieces.

The front two thumb screws have been replaced with nylon setpoints. The supplied Hex key is to loosen and tighen these. The Hex has no elbow so you do not tignten too hard. The  thumb screw out the back is for locking it in place(easy on this one too). The two up front is for fitting in the inside channel.























































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