Hutech Astronomical Products
Equipment for the Serious Amateur Astronomer


Borg Solutions:
SBIG efinder Focuser Enhancement

The Borg 7315 miniature helical focuser and 7316 1-1/4" nosepiece constitute a nice enhancement to SBIG's CCD camera efinder, typically used for autoguiding without a guidescope.
The standard hardware supplied by SBIG includes the 1-1/4" nosepiece (standard with the CCD camera), efinder lens, extension tube, and efinder barrel.

In efinder configuration, the 1-1/4" nosepiece is not used. Instead the efinder barrel is screwed directly into the CCD head and the efinder lens and extension barrel combination is held in place on the opposite end of the barrel with nylon thumbscrews.

With the standard SBIG configuration, focusing is done by loosening the thumbscrews and sliding the lens assembly in and out. At best, this is a clumsy two-handed procedure which must be done while watching the CCD imager's output on a screen. In cold weather, this is extremely difficult to do with gloves on!
To add the Borg helical focuser, put the SBIG-supplied 1-1/4" nosepiece on the CCD head. Then slide the Borg focuser assembly onto the SBIG assembly, pushing it all the way in before tightening the two chrome-plated locking screws.

Finally, screw the SBIG lens assembly into the nose of the Borg assembly but do not include the extension tube. The lens may not screw completely in. In this case, do not force the lens on, but screw it in far enough to insure a secure fit.

When using the completed setup, infinity focus should be reached with the helical focuser at about the middle of its range of travel. Note the focuser scale readings and tighten the focuser lock screw after achieving critical focus. In the future, the focuser reading recorded can be used to rapidly come close to focus even if the assembly has been taken apart.

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