Product Description
F-SV25B 2.5” Dual Speed, Fully Rotating, Rack and Pinion Focuser
Featuring about 95 mm of travel, this import focuser is a precise dual speed unit that is threaded for our field flatteners that have an M63 attachment thread. To get to this thread you loosen the small set screws on the 2" adapter, then un-thread the adapter. The field flattener threads in where the 2" adapter threaded. For visual use, our precision compression ring 2” and 1.25” adapters are included.
We purchased these focusers to use on the 70T. Many customers upgraded the import focusers to a Feather Touch so these were removed and stored. They make an excellent upgrade for our older scopes because they are smoother and carry more weight than our older 2" focusers.
This focuser attaches to our telescopes that use the standard M 88.5 X 1 thread. Examples of telescopes that may be used with this focuser include the Nighthawk Next Generation, SV90T flourite, SV90TBV Flourite, SV102ED, and some SV105’s.
Telescopes that WILL NOT work with this focuser include but are not limited to the old standard Nighthawk, Nighthawk Aplanat, SV80-9D, SVR90T Carbon Fiber, former SV080T carbon fiber tube and 2" focuser, SV102 or 105 telescopes that were made with a 2" Feather Touch focuser and many more. Telescopes we made way back like the 102EDT using the 2" JMI focusers will not work without some modifications.
This focuser uses an M88.5X1 thread to attach it to the telescope. We switched to this thread as a standard when we introduced the Nighthawk Next Generation. If your focuser un-threads from the main tube you can measure the male thread with a caliper. If the male thread diameter is slightly under 85 mm, it will not work. If it is slightly under 88.5 mm it probably will work.
We have made thousands and thousands of telescopes since 1998 and many were custom. Others were upgraded during their lifetime. So there is no way to confirm which telescope will work by simple part numbers. Since not all telescopes will operate with this focuser we suggest you email us a picture of your telescope with focuser from both sides to mail@stellarvue.com before you make this purchase.
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Stellarvue 2.5" Focuser
In my 50 years of owning many telescopes, I purchased a new SkyWatcher 120mm F-5 refractor. I had owned several other makes and brands of this versions within the last 20 years. However, this one proved to have exception optics so good that I decided to upgrade the focuser to something much higher quality to match the excellent objective of this ota. Received the 2.5" Stellarvue focuser and what a surprise... the finest quality 2-speed rack & pinion focuser that i have ever seen or used on any telescope in my 50 years of experience. Thanks Stellarvue for such fine workmanship and quality. I had always heard of the fine company buy had never used their equipment. (my lost) This really completed my little 120 F5 to a very high standard fast refractor. Try Stellarvue's equipment, you will not regret it. I mean TOP quality! Ken Dauzat ...
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Simply Stellar!
I have owned and enjoyed Stellarvue telescopes and accessories for years. So when the Crayford focuser on my SV80ED Nighthawk Next Generation telescope started to show its age, I figured it was time for an upgrade. But not just any upgrade, I wanted to keep it affordable and if possible, keep it all Stellarvue.
Speaking with Alex at Stellarvue, he made a recommendation that fit both desires. His advice was the all-new FSVF25. This is a very beautiful yet very sturdy duel-speed rack and pinion focuser with a 2.5 inch diameter draw tube that includes 2 inch and 1.25 inch adapters.
So how did it all work out? Well, I was elated to find this focuser fit my little refractor like it was custom made for it. And, not only does it look great, it works great. It is smooth and robust. It does not vignette the views nor does it show any signs of wobble or backlash. The whole focuser is rotatable but so precision-made, it does not lose collimation. And oh yes, it has a finder shoe.
So was Alex right to recommend the Stellarvue FSVF25 focuser to meet my needs? There is only one way to answer that. And that is with a very grateful and resounding “YES!” So thank you Alex, I could not be happier and my scope could not be happier! -
Smooth-operation, compact size, great appearance
The Stellarvue 2.5" DUAL-SPEED FOCUSER - FSVF25 replaced the original focuser on my SV90T. (Is it now an SV90T-FSVF25?) It is a bit lighter than the original, but shows strength to hold any likely accessory. Hundreds less expensive than a Feather Touch, I am more than satisfied with my decision to buy it.