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WO vs BO OCA/barlow

Started by j.cantrell, 10/08/2005 01:06AM
Posted 10/08/2005 01:06AM Opening Post
During break in this evenings clouds, I compared the the Burgess OCA with the one that came with my WOBVs.

In order to get the Binoviewer to work in my F5 GSO dob I replaced the bolts in the mirror cell with longer ones in order to move the primary up the tube an extra half inch.

The WO supplied oca still requires a one inch eyepiece barrel extension in order to reach focus, measurement showed the barlow to be about 1.73 when viewing through the BV.

The BO unit allowed me to reach focus without the barrel extension, but even without the extension I measured a 2.15 increase in power.

Physically, the BO unit has a larger aperture, too many passing clouds to determine if there is a difference in brightness.
Posted 10/08/2005 06:49AM | Edited 10/08/2005 06:51AM #1
Jim,

How did you determine that the BO has a larger aperture? Is this something you measured? Or are you just going by the written specifications?

The reason that I ask is because there has been a lot of confusion on what the true clear aperture of these units are and the correct method to measure it.

Thanks
Don Durbin