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Z-12 dob/WO bino viewrs

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#1 skinnyonce

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Posted 02 January 2013 - 08:01 PM

Im still new to this all,,

cant seem to focus can someone help with a work around or their own fixs

wo binoviewrs- 1.6 oca- 20mm ep x 2 + Z-12 dob

#2 sopticals

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Posted 02 January 2013 - 09:49 PM

Been through the same myself. The problem: not enough in-focus. With my home grown 14" dob f5.07, I had to move my spider/focuser down tube towards the primary by 1.5-1.75" to obtain the necessary infocus.

The other options: move your primary up tube,or insert/stack two or three empty filter bodies between 1.6x corrector and bino end, or WO have the options of a) an extender(same function as stacking filter bodies) b) an alterative 2x corrector. If you go with the "options" there is the downside of substantially increased magnification which may not be desirable.

Stephen.(44deg.S.)

#3 skinnyonce

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Posted 02 January 2013 - 09:55 PM

would a low profile focuser get me close or not

#4 Astrojensen

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Posted 03 January 2013 - 03:03 AM

It would get you closer, but not close enough. I'd say your safest bet is to get a TeleVue 2" 2x PowerMate and stick the bino in it. The 2x Powermate is nearly parfocal with your normal focus position, no matter what you put into it and it stays at 2x. Your 1.6x barlow (which I have some serious doubts is as low as 1.6x, even if it could reach focus) will be far above 2x, when you get enough extension tubes to get it to work.

A 2x Powermate and 20mm eyepieces is around 150x, but this will be nearly ideal on a 12" on the Moon and planets on most nights. I use 160x on my own 12" most of the time.


Clear skies!
Thomas, Denmark

#5 Ed D

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Posted 03 January 2013 - 01:14 PM

A couple of ideas come to mind. A Spacer Ring will place the OCA deeper into the focuser tube with a little more magnification. The WO Extension Tube has a lip that limits entry into the focuser tube, which won't help you. The other alternative would be trying a barlow, if you have one, without the OCA. With a 2x barlow the magnification would be more like 4x. With a focal length of 1500mm and 20mm eyepieces the magnification would be about 300x, which is high.

I'm not familiar with the way the 2x Powermate works that Thomas suggested, so I can't comment one way or the other.

Ed D

#6 skinnyonce

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Posted 03 January 2013 - 04:38 PM

this may sound silly but if I put the binoviewer in the 2-1.25 adapter and then attached the 1.6 with the extender from the underside placing it closer to the secondary,,Ill take a pic of what I mean if it works ,,,need a clear nite to test it out

#7 Ed D

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Posted 04 January 2013 - 08:55 AM

I think I follow your idea, and it's not silly at all. Everything to gain, nothing to lose. It may just work!

Ed D

#8 skinnyonce

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Posted 05 January 2013 - 09:52 AM

thanks all for your great help,,






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