Review of Orion Dual-Speed Low-Profile Crayford Focuser + AccuFocus

Posted by XTSee on 16th November , 2008

I have now finished my latest review article about the Orion Dual-Speed Low-Profile Crayford Focuser that I got for my XT10i telescope recently. At the same time I also got the Orion AccuFocus Motorised Focuser to provide vibration-free fine focusing of my telescope. Both these are detailed in the XT10 Telescope Modifications section of my web site.

Orion Dual-Speed Low-Profile Crayford Focuser plus AccuFocus Motorised Focuser

Orion Dual-Speed Low-Profile Crayford Focuser plus AccuFocus Motorised Focuser

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2 Responses to “Review of Orion Dual-Speed Low-Profile Crayford Focuser + AccuFocus”

  1. Z80 (1 comments)

    Hi Jim,

    Nice blog, nice M13 shot (I quite like the colors) and nice and useful reviews indeed.

    I’m answering to your (now old, as I can see here, since the review didn’t mention a date) about the Orion low profile focuser and AcuFocus.

    Well, the reason, to start with, is I was lookinf for information about the focuser and your blog provided even more than I was looking for, so thanks again. :)

    I’d just like to answer some of your unanswered questions, and add some remarks about the hardware.

    - The side threaded holes are just actually holding the focuser body to the plate. You coud even untighten them or replacing the grub screws inside by thumbscrews, so you could rotate the body if it could be handy depending on the altitude you’re pointing, for photography or anything else (though you could still rotate the camera, but for some reason, focuser builder often offer a rootation feature)…

    - This focuser is actually made by Antares (Canada). As for the Taiwanese maker Guang Sheng Optical, they allow many of their resellers to custom their products with their own brands. That’s why you can find this same focuser under Teleskop Services, Orion or Sky-Watcher (and of course Antares) brands… And this explains why it won’t feature the same technical details as the original Orion (a.k.a. Sky-Watcher, BTW) one, such as the flattened section on the spindle. ;)

    - I’m quite amazed on how thick the base actually is. It almost ruins the low profile main feature, though showing them side by side does still show the Antares (let’s call it its original name ^^) is lower by something like, maybe, half or 1/3 of an inch, which is still something.

    As of course, apart from being much better mechanically, its main asset is its reduced height. The reason why I was interested in knowing more about it is I’m struggling to reach focus with a binoviewer, so I guess you can easily imagine how important it is !

    Well, I guess the specific shape is made to cope with various tube diameters. They’s chosed to go for widely open and universal base with probably smaller tubes in mind, while other builders would rather gor for differently curved baseplates to accomodate different tubes diamters, generally going for larger ones (usually up 16″ for the most common, or even more for some of them).

    But as you immediately noticed, it’s widely open to stray light and dust.

    However, remember the side threaded holes ? They mean you can remove the focuser body from the abseplate and fit it into another.

    For instance, a very commonly used replacement focuser is the GSO one. It’s provided with its own (curved) baseplate, but the bolt holes pattern are very different from the Synta (Orion and Sky-Watcher) ones. This led to many resellers to make their own adaptation rings, allowing to fit these focusers to the original Synta baseplate.

    In additon, your original focuser can be collimated to compensate potential tube shape issues, so they made this ring collimatable as well.

    Mine has been made by a friend using a lathe, but the idea has spread quite fast since then. Here’s an example from ScopeStuff :

    http://www.scopestuff.com/ss_fnc4.htm

    It would be interesting to check is your focuser base dovetail shaped groove would have the same size as the GSO one already, so this existing ring could be used ; else maybe you could have a custom ring made by someone owning a lathe.

    This would give you back the collimation feature, in addition to lowering the focuser a bit, and of course eliminating the gap problem. :)

    I can give you a diagram with the exact dimensions for the ring, at least for your original baseplate side (bolt pattern, outer diameter, collimation bolts locations). The inner diamter could need some adjustment is case the Anteres focuser body groove size is different from the GSO’s.

    Byt the way, you might be interested some day in knowing Starlight does offer a specific ring to attach a FeatherTouch 2″ focuser (or even a SIPS) to your original focuser baseplate. :p

    - About the Accufocus, I agree it’s a bit disappointing they didn’t provide a clutch (TeleVue does). However, Orion’s suggestion to unlock the screw on the motor shaft side is actually quite brilliant. In fact, there might even be enough room to replace the grub screw with a flat thumbscrew,so you could easily unlock it without tools. At least it would be worth trying to find one that could fit without touching the bracket. :)

    BTW, maybe the bracket could be drilled to at least allow access to the hidden screws.

    Anyway, thanks again for this complete review. Clear Skies.

    Friendly yours,

  2. XTSee (25 comments)

    Hi Z80, thanks for your interesting comment, extra information and ideas, much appreciated. Your suggestion to replace the grub with a thumb screw is good. Jim


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