> The MoonLite CF2 Refractor Focuser
The MoonLite CF2 Refractor Focuser
MoonLite CF Refractor Focuser
By Edwin Kessler - 8/12/2004
Review by Edwin Kessler
Manufactured by MoonLite Telescope Accessories, Danville, Pennsylvania (www.focuser.com, 570-275-7935).
Many people know that MoonLite makes superb focusers for Newtonians and Dobsonians, but a recent design allows MoonLite’s CF1 (single rate) and CF2 (dual rate) 2” Crayford style focusers to be used with refractors. Currently, MoonLite produces an interface to fit Celestron’s CR6 (150mm, 6” refractor), and anticipates interfaces for the Meade AR5 and AR6. From what I understand, interfaces for other scopes may follow.
The original focuser on my CR6 f/8 refractor is typical of most focusers of the Synta variety. It was functional but coarse and exhibited some flexure when racked out. The flexure could be corrected by tightening the focuser’s tension screw, but that made turning the focuser’s knobs more difficult. Add the crudeness of the focuser to my mount that is just marginal for the big six inch refractor and focusing became a bit of a frustration, especially at high powers.
I ordered the CR2 dual rate focuser which has a sealed 8:1 reduction ball-bearing planetary drive system. In use, tweaking the focus with the reduction drive produces next to zero vibration down the tube and there was no discernable backlash. Focuser travel is 4.5 inches and the unit is rated for a 10 lb. load. The drawtube pressure (and the lifting capacity) can be adjusted with a nylon thumbscrew. As shown in the photos the knob on the reduction side of the focuser extends out about 1.25 inches from the side for improved accessibility.
Additional features are highly polished and anodized surfaces and a 1.25 inch adapter. The inside of the drawtube is well-baffled. My CR2 is red and black and is beautiful to look at. In fact, when I first opened the package and saw the focuser, my thought was “this is too nice for the Celestron!” It is noticeably different from the rest of the scope’s fit and finish even to the uninitiate. My wife’s response: “That’s pretty!” And, I suppose, that is the question to answer. Should one put a $375.00 focuser on an OTA that costs only a bit more? My answer is that many CR6’s can be modified into excellent scopes with a new focuser and a Chromacor for a fraction of the cost of a six inch apochromat. I bought the CR6 with such intentions from the start. The MoonLite also adds more weight to compensate for the top-heavy Celestron, improving the scopes inherent imbalance.
Installation is straightforward. Take off the original focuser by removing it’s three mounting bolts, insert the MoonLite in it’s place by using the bolts supplied, and you’re finished. The MoonLite came collimated from the factory and, indeed, after I installed it and checked the scope’s collimation, it was right on. Should the need for collimation arise, the interface has push-pull alignment screws and bolts. And this leads to my only complaint about the focuser: to adjust the collimation, one needs to remove the focuser from the telescope’s tube. It wasn’t my experience, but I can imagine an exasperating time, removing the focuser, tweaking the collimation screws, installing the focuser and repeating the procedure several times until it is aligned.
The MoonLite CR2 is incredibly smooth to operate and is the best focuser that I have ever used or tried. It is difficult to describe the difference between the MoonLite focuser and the original. Performance and ease of use is so much better that it is like night and day, or like driving a Mercedes versus pedaling down the street on a tricycle – both will get you there but . . . . It's no exaggeration to say that of all my scopes, the high end apo's included, my humble CR6 now has the best focuser of the bunch. Essentially, from a mechanical perspective, the MoonLite transforms a useable scope into a delightful scope.