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Siebert Multi-Mag OCA

Started by fblue, 02/08/2006 11:49PM
Posted 02/08/2006 11:49PM | Edited 02/08/2006 11:49PM Opening Post
I have had a good experience with a Siebert product lately. The Multi-Mag OCA for my WO Binoviewer.
The WO Binoviewer came with an OCA (Optical Corrector Assembly) but it would not come to focus and it was only 17mm of open aperture, which is not too good for a 22mm (20.5mm) aperture Binoviewer. :S It was worthless really, so I needed something to bring the Binoviewer to focus in my Dobs. Plus I wanted some flexibility in magnification.
I was told of the Siebert Multi-Mag OCA 1.25x 2x 3.5x unit and I ordered it from Harry. I found that it also worked with the lens only screwed into the Binoviewer with out any of the tubes or corrector lens ( not shown in the instructions and I informed Harry of this configuration). This produced about 2.8-3x so it really has 4 different powers of magnification, 1.25x, 2x, 2.8-3x, 3.5x. Quite a feat really! shocked
I have used it in all its configurations and found it to be a highly corrected unit. Very good OCA that makes my 3 pairs of EPs seem like an entire set of f/l EPs.
My 15mm TV Plossls at 3.5x (4.28mm effective f/l & 356x) were excellent on the Moon and showed the Trapezium with great clarity. I counted 39 craters in the Clavius crater, not bad! The seeing on this night was not perfect by any means but I think I could have gone higher in power if I had the EPs with a shorter f/l.
The 20mm WO wide fields and the 1.25x configuration was unbelievable on M42! 8O Very impressive!
Saturn with the 20mm WO EPs and the 2x configuration gave a really 3D like image that was clean and crisp as did the 15mm TV Plossls.
Highly recommended.

[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue grin
Amateur Imager
Posted 02/09/2006 01:06PM #1
Are you tempted to invest in a more expensive binoviewer? I have read some conflicting opinions on this recently, but can't forget the old axiom 'you get what you pay for.'