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Denkmeier ll with TV Genesis non sdf question

Started by RobbieLuj, 10/31/2020 10:08AM
Posted 10/31/2020 10:08AM Opening Post
Hey hey, I recently acquired a Denkmeier ll Binoviwer with the power x slide. It seems to work really well with my lx200 8” as is and seems to get into focus. But, When I go to use it with my TV Genesis 100mm f5 non sdf refractor, it doesn’t focus. My question is, what would I need to make this work with my Genesis refractor? I know there is some sort of OCS system but I’m not sure what it is and what it does. What does this do and will this work for me? And if anyone knows what all the OCS pieces do.  Or do I need a tube extension? Looking for any help, I am new to binoviewers. Also, when out of focus on a planet my donut is a little football shaped and the black inner dot is really toward one edge versus in the middle. Does that mean my bino is out of collimation? It’s not like that with just a mono lens. Although it does get into good focus despite the odd donut. But seems like that’s probably not right overall.  Love what I am seeing so far but a little help would be appreciated to make sure I am optimizing my viewing with my bino. Thank in advance!
Posted 11/30/2020 08:09PM #1
The binoviewer does not require an OCS (optical corrector system) for use with an SCT.  Hewtonian reflectors or refractors require the OCS lens to bring you to focus.  For your refractor, it usually screws into the telescope end of your diagonal.  Whoever sold you the Denk II should have included the OCS, which would automatically come with it when purchased new.  Exception:  If it was purchased direct from Russ at Denkmeier and Russ knew it was for an SCT, the total price may have been adjusted to eliminate the OCS, since it was not needed.
You will need to contact Russ Lederman at Denkmeier to obtain the OCS.
Posted 12/05/2020 03:52AM #2
Just to clarify the reason a newt/dob or a refractor will not come to focus is they require more in travel on the focuser so no an extension will not help you.

Unless you are willing to shorten the newt/dob or for instance the tube on a refractor so that the focuser is closer to the mirror/objective then you need to use either an ocs or a barlow (an ocs is for all practical purposes a barlow lens).

If you did shorten the tube on a refractor to have more in travel then that is when you would need to use an extension in order to still use single EP's without the binoviewer.

I almost exclusively use a binoviewer with all my scopes and modify them accordingly to keep from having to use an ocs as I find the extra glass in the path dims the view more than I would like.....

20" MidnighTelescopes f/5
8" f/16 Muffoletto Achro
Meade 6" AR6 f/8.0 Achro
Celestron C11
Parallax PI250 10" F/5 Newt
Vixen FL102S,NA140SS,R200SS
80mm Stellarvue Nighthawk with WO APOupgrade lens, 90mm f/16.67 Parallax Achro
LXD75/LX200, Mini-tower, GP-DX, CG5 ASGT, LXD650, GM-8, G11, GM-100, GM-150EX, GM-200 and a Gemini G40
4" portable AP convertable 44" or 70" pier
Stellarvue M7 Alt-Az, TSL7 Pier/Tripod
12.5" f/5 MidnighTelescopes DOB Swayze optics
Monroe GA