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Instructions for Siebert Optics mod for Burgess/WO Barlow attachment sold with the binoviewers 

This combines the Burgess or WO barlow with a Siebert Optics Element to allow for a combination of magnifications as illustrated below. Read the the information below for complete details.

The lowest power for refractors is 1.6x and dobs x2. Check details below

1.

The picture above is the Siebert element in the Burgess binoviewer. The tolerance in the nose of some these binoviewer may make the threading tight after three or 4 turns. This is ok if it threads enough to hold properly..

2

The Picture has the Burgess barlow in place and gets x2 mag. The WO element will get 1.5x in this configuration. If you don't get in focus with the WO element, you might need to relocate it from the bottom of the binoviewer to the front of the 1.25" diagonal (As illustrated in pic 2b). Then your mag will be x2..

2b

You will then have x2 power for your refractor.

3

Next you will pair the the Siebert element with your Burgess or WO element for x3

4

After the sleeve you then thread your barlow, Burgess/WO on to the end for x3. This setup is for Dobs and refractors alike and will likely work in a  2" diagonal just as well as a 1.25" diagonal. 

You will need to use a 2" to 1.25" step down adapter in 2" diagonals. You may also remove the parfocal ring that I accidentally left on the Burgess nosepiece in the picture. 

5

In the picture below are some precautions that should be taken with a 2" diagonal.

6

7

Below indicates that the supplied ring spacer might need to be use to keep the corrector from going too deep into the diagonal.

It is possible that the WO element might not focus in a 2" diagonal. In this case use the 1.25" setups for the WO Barlow element in picture 2 and 2b. 

Important Information

For Williams Optics 2" diagonals and others with low profile 2" to 1.25" stepdown adapters you will likely need to use the parfocal ring to keep the OC from extending too far into the diagonal.  Be careful not to come into contact with the mirror.