VSE\'s Home Page Versa-Port Sliders Mega-Port Sidewinder Accu-Port Targetron Imaging Train Rotator MacroGlide Focusers MasterGlide Focusers MicroGlide Focusers Hexagonal Turrets BiFilar Micrometer Spiders VSE\'s Home Page Epsilon Focuser Omicron Focuser MicroGlide COUPLING Focuser Docking Adapters Drawtubes MicroGlide Autofocus Accessories

Order Info FAQ astroimaging User Installations User Comments Astro Links configurations help Custom Machining

2" & 2.7" MicroGlide Docking Focusers (Patented)

A Revolutionary Focuser with Tactile Sensitivity Second to None

And, the Finest (ratio) AUTOFOCUS for Astroimaging on Planet Earth!

If you're THINKING  about a FOCUSER, THINK GLIDERS for the FOLLOWING REASONS

Mount any VSI Focuser to any Scope - Not just Meade & Celestron

AP, Borg, DFM, OGS, RC Optical, Takahashi, TeleVue, TMB, Vixen, etc., etc. - Just Call VSI

Features & Specifications: MicroGlide Focusers (2" format)

VSI's [2" format] MicroGlide Focuser (patented) is the first [ever] 5th-bearing Crayford design. This revolutionary new encapsulated, five radial ball-bearing, frictionless design provides slippery-smooth, precision moving tube travel that is beyond anything you have ever experienced - guaranteed, or your money back!

The patented Van Slyke drive (VSD) is hidden inside the focuser's small aluminum box. This new focusing mechanism will not be disclosed. However, the focusing action is controlled from a precision Mitutoyo (made in Japan) micrometer head. This micrometer head incorporates indices of 0.001" and can be interpolated to 0.0001" with ease, and the moving tube has a full half-inch of travel - it doesn't get any better than that! And this focusing position accuracy is repeatable, so you can use it for astroimaging, or any repetitious focusing task.

MicroGliders include our exclusive Finger Spinner (pictured left). Simply insert your index finger in any one of the six [inverted hemisphere] ball cavities and spin away. You can't do this with ordinary focusers, with less-sensitive tactile control, because you would have your scope/image wobbling all over the place/sky. Only the ultra-sensitive, no-resistance, action of the MicroGlider's micrometer head, coupled with the finger spinner, would allow this tactile finger spinning action with ease. The finger spinner also increases your resolution and torque, making it that much easier to manipulate your focusing position manually. Ease of movement and ultra-sensitive tactile control doesn't get any better. And, for changes in focus position, just spin the finger spinner with your index finger. It doesn't get any quicker, either!

Many other focusers are either too coarse or too fine, or they offer both coarse and fine control knobs, but neither approaches that manual/visual "sweet spot" of focus control. What good is a focuser that has coarse and fine control when both actions are either too coarse one way, or too fine the other? VSI has always gone to extra [machining] effort to provide that special ratio that visual astronomers want - usually on the fast side of fine. Not too coarse, so you can't achieve true visual focus, and not too fine, where you can't achieve focus with a single [rotational] movement of your wrist. Visual astronomers, who have experience with other focusers, have told me that the other dual control focusers are way too coarse and their fine control is way to fine for visual work. They say that VSI focuser's single control knob is just right for visual/manual control. Our MicroGlide focusers also provide the finest autofocus ratio available for astroimaging, where one motor step = 0.0000069" of tube travel. This equates to the finest autofocus control on Planet Earth, by a very wide margin! We dare you to even come close to those autofocus specs anywhere else. The next closest motor controlled autofocus ratio is [you guessed it] our MasterGlide focuser at 0.000052" of tube travel per motor step, which is also finer than any other autofocuser on the market. This simplifies your autofocus decisions substantially, either MasterGlide or MicroGlide. Note that the manual microfocusing tangent arm, on our MasterGlide focuser, is way beyond ultra-fine at 5/1000" tube movement per revolution of the manual control knob, but it is intentionally designed that way for hands-on micro changes in focus for astroimaging, a different focusing situation all together.

VSI offers a unique MicroGlider strategy resolving the profile problem regarding focusing range/travel. MicroGlide Omicrons (MGF2) have interchangeable (optional) drawtubes that have a 2.25" outside diameter for zero profile insertion, while the Omicron's moving tube has a 2.25" inside diameter. This combination allows the entire drawtube to be inserted into the focuser's moving tube with only the locking thumb screws protruding above the tube. This solution to the profile problem still allows full 2" format usage with the drawtube fully inserted in the focuser's moving tube. Profile problem solved! Conventionally, with a 2" OD drawtube, you would have at least 2" extending beyond the moving tube to accommodate 2" format barrel nose eyepieces, etc. This would be OK, if you have the profile to spare, but an unacceptable profile loss when considering limited back focus refractors and other optical configurations designed with limited (or should I say "short-sighted") back focus.

You have three MicroGlide model choices: 1) Our Epsilon MGF1, without the built-in drawtube for SCTs such as Meade/Celestron, where your SCT already has long-range primary focusing built-in, and you need a sturdy secondary short-travel focuser. For your consideration, you could also use our Omicron docked to your SCT with our 2" SCT drawtube for added redundant focus range, simply to increase your convenience and versatility. 2) Our Omicron MGF2, with built-in long-range drawtube capability - up to 12" of travel! This model is designed for refractors, catadioptrics, etc. as a primary focusing device for long changes in back focus, while still maintaining superb micro-focusing capabilities. Consider longer drawtubes with scopes that allow the drawtube to be extended through their visual backs (see picture above, far right). With catadioptric scopes, the center perforation in your primary mirror would have to be 2.25" or larger to accommodate a long drawtube being inserted through your primary mirror. While your MicroGlide focuser only has an actual 0.5 inches of focus travel, you would then have up to 12" of focus range (use our custom drawtubes offered below) by simply loosening your thumb screws and push-pulling your drawtube (see picture above). In fact, for changing your coarse focus point, the push-pull method is the fastest available. Simply push/pull to ballpark your new focus point and fine focus by turning, or spinning, the micrometer head. A fast, simple, elegant, and functional solution to having your ultra-fine focus control (cake) and coupling it to an extremely long focus range (eating it too). 3) The coupling focuser MGFCO is offered in three formats for AstroPhysics, Takahashi and Meade refractors. It is simply a coupling with a built-in focuser that can provide manual or autofocus without modifying your scope's existing manual focuser.

Speaking of cake, here's some "ice cream" to top it off. MicroGliders offer motorized AUTOFOCUS positioning for astroimaging too! VSI offers a MicroGlider stepper motor mounting hardware kit (MTH1) that provides simple and elegant "turn of a thumb screw" manual or motorized operation. Autofocus stepper motors are mounted to the MicroGlider using our exclusive 1/4" ground and hardened steel caliper rods, accurate to 0.0001" in diameter. Our precision machined, fixed caliper clamp, mounted on the motor, rides the rod [back and forth] providing zero [and I do mean zero] backlash (see picture at left). No "hard-wired" motors, no dysfunctional friction clutches, no backlash inherent cog pulleys, no "flip-flop" [gravity sensitive] SCT mechanisms, and no "slip & slide" rubber band drives. This simple stepper motor mounting mechanism offers you the ability to easily switch from autofocus to manual control [or vice versa] as fast as you can loosen, or tighten a thumb screw!

The MASTERGlide QUAD-LOCK feature is incorporated on all MICROGlide focusers (see picture at right). This exclusive VSI locking feature is a super-solid coupling between the focuser's moving tube and your 2" barrel nose eyepiece, diagonal, or accessory. Focusers have always been designed to support a single diagonal and eyepiece using only one or two thumb screws, which was adequate for lighter loads. When imaging trains emerged, this basic philosophy was never upgraded to support these heavier loads. Since the beginning of focuser design, locking thumb screws have always been a weak link regarding astroimaging. Many focusers have only one locking thumb screw, which is adequate for visual observing with a single eyepiece or even diagonal and eyepiece. All higher quality focusers have two thumb screws that should be opposed by 90 degrees for maximum holding power. Many are opposed by 120 degrees, which does not lock a 2" format barrel nose at the maximum [perpendicular] support angle (similar to Crayford bearings which are opposed by 120 degrees instead of the more supportive 90 degrees, but that is another story). Dual thumb screws are not adequate for even the simplest imaging train, let alone a leveraged extended one that can weigh 3 to 4 times as much as a simple 2" format diagonal/eyepiece combination. VSI's exclusive QUAD-LOCK feature offer FOUR thumb screws that securely support the most elaborate imaging trains. QUAD-LOCK's holding power is equivalent, or superior, to the best threaded couplings. And, this new feature is not overkill for astroimaging. It is a necessity to guarantee zero-flexure at this extremely critical junction.

The perfect marriage (if there is such a thing) between focuser and rotator! Combining our manual Zerotator and MicroGlide focuser (pictured at right) creates a rock-solid, stable rotating platform for astroimaging or just rotating your diagonal or Hexagonal to a more comfortable viewing position. The radial ball bearing loaded Zerotator can handle any load you stack on it, because it was designed to hold your entire imaging train - focuser, optical manifold, CCD camera, etc., etc. And it has a 2.75" internal clear aperture so vignetting is not a problem.

You may also focus manually, without removing the motor, by simply loosening the single SS thumb screw (see pictures above), which disengages the motor shaft, allowing you to rotate the finger spinner knob by hand. But it is easier removing the motor to acquire full access to the spinner knob. However, this manual ability would be very convenient when attempting to acquire ball-park focus without having powered motor-slewing capability (i.e. the motor isn't plugged in, no power supply, your computer isn't "up" yet, etc.). As we know, an extremely gear-reduced stepper motor's drive shaft does not turn unless it is under power. Removal of the motor is accomplished by simply loosening the thumb screw (no tools involved), and sliding the motor off the two shafts (one motor shaft and one 1/4" alignment shaft). To replace, slide the motor onto the MicroGlider and tighten the thumb screw (see pictures above). For more info, see AUTOFOCUS link.

VSI MicroGlide focusers are designed to dock with any scope on the market, either with our standard docking adapter rings, or custom machined rings. Our most common docking ring installs our MicroGlide focusers on the current generation of Meade/Celestron Schmidt-Cassegrain telescopes (smaller than 10") that focus by moving their primary mirrors (which always have an unacceptable amount of lateral image shift when focusing), and accept accessories via their standardized 2"-24tpi threaded visual backs. However, MicroGliders can also be installed on any scope utilizing our other docking rings. MicroGliders have the shortest profile of any focuser (less than 2"), so you can easily piggyback an [ultra-fine focus] MGF on the output of your scope's stock [coarse] focuser, and have back focus to spare for a Slider and a CCD camera (see the Takahashi pictured at right). Note this is the new, extended back focus Takahashi. Not the old "no-back-focus" Taks of the past, which would barely accept a standard diagonal and eyepiece before exhausting their [very limited] back focus. For more info on this rock-solid, slick (or should I say "Slyke") Tak imaging train installation, see User Installations link. If we don't have a stock docking ring for your particular scope, we'll custom machine one. All docking rings have a circular dovetail cut into the OD of the ring to securely lock into the MicroGlider's housing via three 8-32 set screws (see DOCKING ADAPTERS link).

WARNING: Be aware that all [so-called] Crayford focusers, are not really Crayford focusers. Deceptive advertising by many dealers, trying to take advantage of the Crayford's reputation, offer Crayford-type, Crayford-like or Crayford-style focusers that have very little to do with the true Crayford design. NO radial ball bearings, NO zero-image-shift, NO fluid motion, NO ultra-tactile sensitive control, NONE of the above functions that made the Crayford the finest precision focuser on Planet Earth. These non-Crayford focusers typically use plastic pads to simulate Crayford bearings and other inferior construction techniques that deminish the Crayford name. Only a focuser that uses four (or five, like VSI's MicroGlider) precision ground steel, radial ball bearings can [rightfully] be called a Crayford focuser. - PVS

MicroGlide Omicron Focusers & Sidewinders  - the Perfect Marriage!

MicroGlide Omicron focusers and Sidewinders, equipped with autofocus, create the ultimate dream imaging train for professional and amateur astronomers alike (see picture at right). Although the imaging train pictured at right is configured to support the large-chip SBIG STL, it is shown without the CCD camera for clarification. However, all you would need to do, to complete this specific imaging train, is screw on a STL camera, autofocus the CCD camera (utilizing the stepper motor mounted to the Omicron, see picture, far left), push/pull parfocus all your side ports, and begin imaging.

Why try to "Mickey Mouse" your scope's existing focuser with an aftermarket autofocus system, just to find out that the step to tube movement ratio is too coarse? Simply couple an Omicron focuser to the output of a Sidewinder and you achieve the finest autofocus ratio, by a factor of 10, available anywhere. Use an Omicron focuser, with our new SBIG STL 2.156"-24tpi insert tube adapter (Item #AMGST, pictured upper left, also see SIDEWINDERS link, ADAPTERS link) and you achieve a full 2" internal clear aperture (SBIG recommends a minimum of 1.95" for their STL). To facilitate docking your Omicron to the rear camera port of the Sidewinder, we have created a new double flanged port ring (Item #MR2729, pictured lower left, also see DOCKING ADAPTERS link above). This port ring also saves the cost of a second threaded port ring, and decreases profile by about a half-inch compared to using two redundant threaded port rings. Although this Sidewinder/Omicron combination has been optimized for the new chips, that are too large for the existing 2" format, you could also use the Epsilon with the Sidewinder to utilize any smaller chip size CCD camera on the market. You are only limited by your imagination.

With the 3" profile of the Sidewinder and the 2" profile of the Omicron, you have a 5" overall profile, which is short enough to work with any SCT or extended backfocus refractor, like the Takahashi TOA series. Note that all the side ports have been parfocused to match the extended 2" profile of the Omicron. In fact, a 2" format eyepiece, inserted directly into the Sidewinder's top port, is just about parfocus with the Omicron installed on the Sidewinder's rear port. Also note that the side pick-off port can be extended with a 1.25" diagonal and achieve parfocus with your imaging CCD camera. With the diagonal installed, you also provide a more comfortable guiding position. Or you could also auto-guide with a SBIG STV CCD camera, etc. Enjoy the possibilities, because we all know that it's just as much about the cool gear, as it is about the imaging. It doesn't get more outrageous than this!

About the 2.7" MicroGlide [in-line] COUPLING Focuser

We believe this endeavor to be another VSI first - an in-line coupling that focuses. For short, we call it a Co-Focuser. It is simply a 2.7" male threaded coupling on one end and a 2.7" female [same size and thread pitch] threaded coupling on the other (see picture below). It is basically a re-machined Epsilon/Omicron with threaded couplings. The Co-Focuser operates just like its predecessors, the Epsilon and Omicron. Turn the micrometer knob and the knurled thread [top] end of the focuser moves outward (see picture left), providing a full half-inch of travel. Overkill range for a secondary focuser.

The internal clear aperture is a full 2.25 inches (see picture at right). More than enough for today's gigantic CCD chips. All the newer APO refractors are shortening their tubes to provide extended back focus - it's about time too! This allows you to take advantage of all the cool imaging train accessories available today - like VSI stuff. This new 2.7" co-focuser is basically identical to the above 2" MicroGlide 1 & 2 in focusing operation and tube movement, except the outer housing moves when focusing, instead of the inner tube. You read it right, the first moving outer housing focuser! This new revolutionary reverse-focusing operation offers superior, rock-solid outer-housing movement over conventional [inner] moving tube focusers. The only other difference is the focuser's input and output is threaded to match either an Astro-Physics 2.7"-24tpi thread, a Takahashi 72mm-1mm thread, or a Meade 2.7"-16tpi thread. Your choice of formats. No adapter rings are used on this focuser to maintain the extremely short 2" profile, which is actually a relative 1" profile when you subtract all your scope's adapters that are eliminated by the installation of the MGFCO. Conservation of profile should always be maintained, even with the extended back focus of these new refractors.

Actually, the most important reason for the creation of this co-focuser is autofocus. Why attempt to modify your existing focuser for autofocus when all you have to do is screw on a co-focuser equipped with our hardware kit and our Robo-Focus stepper motor. After all, the large-format rack & pinion focusers on those APOs are usually pretty high quality, so why replace it or try to "Mickey Mouse" it with an aftermarket universal motor mounting kit. None of these new APO manual focusers are easily modified to provide autofocus. Even if you effectively modify your existing focuser, it is usually too coarse to provide adequate autofocus stepper motor ratios, which means you end up with soft astroimages. And these aftermarket universal kits, for mounting a stepper motor to your focuser, leave a lot to be desired in function, accuracy and rigidity, not to mention style and a clean looking installation. Remember, our MicroGlide focusers, including our new co-focuser, offer an insane stepper motor to tube movement ratio that is a factor of ten finer than any other autofocuser on the market - one motor step = 0.0000069" of actual tube travel! And that's not overkill. It's just a ratio that will make all your astroimages as razor sharp as is mechanically and optically possible.

Of course, you don't have to purchase a 2.7" co-focuser for autofocus only. You may just want a super-fine secondary focuser on your refractor to use in conjunction with your scope's existing, coarse primary focuser. This co-focuser is so ultra-fine that you can achieve perfect manual astroimaging focus and return to the exact [repeatable] "in-focus" position every time using the micrometer head's built-in analog indices, and there's zero backlash. So, do you really need autofocus with VSI's new co-focuser? Only if you're focusing from a remote location. If you are focusing locally, you might even enjoy some "hands-on" for a change. Exercise is good!

Some Ancient History about the "NEW" MicroGlide Focuser

Actually, you may have seen a variant of this focuser at star parties or, coincidentally, you may even know someone who has one of VSI's ancient "Micro-Gage" focusers. If you have an old issue of Sky & Telescope magazine, from October 1998, take a look on page 85 and you'll find the original version of this new MicroGlide focuser (copy of 1/2-page display ad pictured at right).

I even had the foresight to begin patent applications (note the patent pending in the ad, lower right corner). Well, as you know, patents take many years to become reality, and many years have passed since then, so the design is now officially patented. Unfortunately, I discontinued it after the first short production run because I simply wasn't satisfied with its operation or performance. Oh, it was an okay focuser, but I don't offer a product that isn't up to my own personal standards of excellence. It's simply a VSI philosophy/trademark of excellence that you can always count on.

The old Micro-Gage needed work to make it a "true" VSI product. And, back in the early days, time wasn't on the Micro-Gage focuser's side. I was on a quest to create the "perfect" product and, in the process, I discontinued many lines of redundant [if not Meade-iocre] products (Flippers were discontinued and replaced by Sliders, Super Power and Micro-Gage focusers were replaced by Monsters, etc.) on a massive scale. Now, Monsters have been replaced by MasterGlides, etc. I could then concentrate on a few good products (like a few good men) that were functional, feature packed, simple in design, and [of course] indestructable. If you haven't been there, believe it or not, simplicity and functionality are very difficult combinations.

Unlike the massive MasterGlide focuser, which was intentionally designed for larger scopes, it was finally time for a new focuser design that could be optimized for smaller scopes, like 8" SCTs and scopes of similar proportions, and offer an autofocus (co-focuser) capability to your existing scope's focuser by only adding 2" of profile to your existing imaging train. So the new MicroGlider (old Micro-Gage) finally became the perfect solution to creating a smaller format, super versatile, ultra-sensitive focuser that also does autofocus.

The new MicroGliders are literally like no other focuser ever created. When you experience the elegant purity and simplicity of this [ultra-sensitive tactile contact] focuser, you will be convinced of its worth as a pre-eminent new movement format that, hopefully, will be considered adjacent to the rack & pinion, the helical, and even the formidable Crayford. This totally new moving tube mechanism (aka the Van Slyke drive) is nowhere near any of the other common, industry-standard designs. And it's extremely comparable in operation (i.e. the renowned coined phrase that denotes the Crayford - "zero-image-shift") to the Crayford, which I consider to be the most simple and functional focuser operating design ever created (thank you John Wall), when done correctly.

Unfortunately, even the venerable Crayford can be "butchered" by those who build the cheapest products humanly possible - but the price is good! Actually, VSI products are priced only slightly above other mediocre products, but when you consider a build-quality and features that are at least 10 times greater, you begin to understand VSI's truely wholesale marketing philosophy that offer incredible savings, direct to you, the customer - such a deal! - PVS

[return to home]

[top of the page]