Unsolicited and Unedited User Comments about VSI Products

SLIDER 2 SKY & TELESCOPE Test Report (July 2002)

Hi Paul –

The Zerotator arrived yesterday and I was checking it all out. Being an Engineer myself, I really like the design and adjustment features of your Rotator. It’s a very fine instrument. I’m very impressed by the quality. I attached it to my Telescope and attached all my Camera gear and found everything is totally compatible and fits like a glove.! Very pleased.

Thanks for your help & the quality Rotator.

Best Regards,

Steve Antosiak, Algonquin, Illinois

Good day Paul,

The Spider hub assembly and custom length vanes were received yesterday in the most perfect condition!

Two words will suffice: ABSOLUTELY DELIGHTED !!

Many thanks for a world-class quality product and flawless workmanship.

Fear none, you have no competition out there. You're simply THE very best !!!

Clear Skies,

Stephane L'Heureux, Quebec, Canada

Dear Paul,

A few months ago, I received your VSI 3.25” – 2” (6x) HEX2 Turret, to be used on my Celestron CGE1400. I’ve loaded the Turret with my Pentax XWs (set of 6, 7mm – 40mm) and so far I’ve used it several times under dark skies. Using your Turret is a delight: I now switch eyepieces for every object I’m observing, without any compromise – and this is a big difference compared to my pre-turret past. The ‘observing experience’ got an additional dimension: I checked several magnifications in order to find the best for the object – and that’s totally new to me. I can’t do without [the HEX2] anymore! What to do with my diagonal??

The filter slide is a delight as well: very quick and easy – good for comparison. This is also new to me.

I’m impressed by the fit and finish of all components. It’s true: it’s visible that the turret is a hand-made masterpiece, but this provides an additional dimension as well.

Shipping of the unit from the USA to the Netherlands was no problem as well: it arrived at my house 14 days after dispatch (after staying approx 1 week at Dutch customs) – very well packed without any damage at all.

Final conclusion: I should have bought this unit years ago.…

Txs a lot for your help and support, and your great product.

Frank Hol, The Netherlands

Also see USER INSTALLATIONS link for pictures of Frank's scope. Then scroll to "Frank Hol's Celestron 14" Scope set-up in the Field." - PBVS

I have strong opinions about the value of turrets. They in NO way degrade the image. I have used most of the high end turrets - Tak, TEC, and Zeiss. They are all excellent , but the VSI HEX 1 Turret is my current choice. The HEX 1 provides several functions that are absent in the others. The construction quality is also much better in my opinion. For eyepieces I decided to use Brandons. There are now six [non-Questar] Brandons being manufactured. The 32mm, 24mm, 16mm, 12mm, 8mm, and 6mm. With focusing care (focus at high power first) these eyepieces are parfocal - not approximately, but dead on. I never have to change eyepieces or focus and simply click to easily change powers.

Robert Brown

Also see USER INSTALLATIONS link for pictures and further comments by Robert Brown. Then scroll to "The Backyard Visual Telescope of Robert Brown." - PBVS


I just wanted to let you know how pleased I am with the Toadloader. I tried it out last night and was able to achieve the best repeatable focus I have ever obtained. Your product is a beautiful example of function, fit, finish, form and execution.

Thank you

Dave Chaton, Gardnerville, NV


The serious amateur astronomer, institution, or observatory, should seriously consider the instruments developed and engineered by Paul Van Slyke at VSI to be nothing less than world class. Working with Paul to develop my imaging train was an enjoyable experience. If serious astroimaging is on your list, then you need a rock solid platform - VSI is the answer.

VSI focusers provide the ability to support heavy loads, with absolute zero flexure, particularly when I use SLR film cameras, and a very heavy and large medium format camera. In my opinion, upgrading to a 2" Toadloader provided me with a focuser that is smooth as silk, incredibly solid and built to observatory class standards. And it has a MicroDial that is ultra sensitive and micrometer accurate. I was so impressed with the workmanship and attention to detail, that I drove 12 hours, from Arizona to Colorado, to meet Paul and discuss the design and fabrication of a visual back adapter tube and focuser assembly for my piggy-backed 110mm William Optics refractor.

Needless to say, Paul was able to custom machine and install a 4" moving tube in my existing 2" Toadloader, and an extended visual back assembly which he created to exacting standards.

As an astronomer and builder of an observatory himself (Black Forest Observatory), Paul has that special ability, along with an "anything is possible" attitude, and the knowledge to fabricate only the finest astronomical instruments. All are handmade to your particular design needs. My goal for Province West Observatory, along with astroimaging, is to contribute observations and update existing lists in the measurement and study of binary stars. Using data from the US Naval Observatory double star program, target lists will be compiled on binary stars that need to have new measurements. I will soon be ordering the NEEDLEYE Bifilar Micrometer from VSI to assist me in making this project/program become a reality.

Thank you Paul, and VSI for designing and developing these world class instruments!


Bruce Anderson, Province West Observatory, Maricopa, AZ

For more info and pictures of Bruce's installation, see my USER INSTALLATIONS and CUSTOM MACHINING links. - PBVS

Hello Paul

I have taken the first pictures with my new set-up and I am very satisfied. The guiding with the Targetron is always under one pixel in both axes at 2500 mm focal length. Surely my Alt-5 ADN mount helps a lot. Also the focusing with the 3" Toadloader is very accurate, and the [Robo-Focus] temperature compensation reveals no changes during a night.

Dr. Edmund Georgii, Landos, France

Also see Dr. Ed's super install at my USER INSTALLATIONS link. - PBVS


I received my two VSI SH3 robofocus/spider kits some weeks back. Very impressed with the units you supplied. I'm glad I decided to use tool-grade 5/8" thick plate to machine the tube rings for the 2 VSI spider assemblies. I will need it to cope with the massive VSI units. Makes the commercial truss tube ritchey-chretiens out there appear very flimsy. I will send some photos when I finish the scopes, hopefully in a few months time. Thanks.

Guy Fleming, NSW Australia

~ Follow up on the VSI Spider assembly install ~

Hi Paul

I'm still mucking around with perfecting polar alignment of the Paramount and 12RC and getting all of the gadgets working with the automation software. Your VSI SH3 [spider] works well with the Robofocus for automated focusing. FocusMax worked pretty much straight away. Next ATM project is to rebuild a couple of Vixen VC200L cass tube assemblies - I am using the existing primary and secondary assemblies and replacing the steel tube with a CF truss. Also considering adapting a 3" low profile focuser to the rear of one of them, replacing the exisitng R&P.


Guy Fleming, NSW Australia

 I received the [Super] Stack today; what a beauty! I assembled it and installed it on my C14 and am ready to go (well, I do have to rebalance things a bit!). Thanks again for your beautiful and functional products.


Robert Pitt, Ph.D., P.E., DEE, D.WRE, Cudworth Professor of Urban Water Systems

Department of Civil, Construction, and Environmental Engineering

University of Alabama

Hi Paul,

I wanted to let you know that I am very pleased with your Hexagonal 2 Turret. Not only it is extremely well built, but it is also beautifully machined and provides a fast and reliable way to swap eyepieces in the dark for visual observation or to compare them against each other. Changing filters using the provided holder is also very convenient. I am also very pleased with the 3" OMEGA focuser and Sidewinder [optical manifold].

As always, your products integrate very well together.

Serge Taran, El cerrito, CA

Hi Paul,

I have become an MicroGlide Omicron focuser Fan! I can focus more sharply with my Omicron than I have ever been able to focus before. As you know good CCD imaging is mostly about focusing and with the Omicron I have so much more control than I ever had before.

I have a 228-mm refractor and like to image the planets and Moon, so I use a Baader barlow lens-field flattener at F/27 to F/31 which is pushing our seeing to it's outer limits. Even then I have noticed that with my Omicron I can get a much more precise focus even though I have great depth of field at that high F ratio. In fact, I now tweak the focus while inside the critical focus zone and find that I'm getting a lower FWHM than ever before. That's proof that I wasn't getting the best focus.

My Sidewinder with Omicron attached is another story. I use this combination for prime (F/9) focus imaging or with a focal reducer at F/6. Either way, I can easily center the object and with the omicron take a focus that's sharper than I have ever experienced. My next project is to use the pickoff mirror with my guider chip so I'll be using the main scope as guide scope and won't have the usual problem of losing the guide star when the blue filter swings into position.

These products are great and they make amateur astronomy an even more rewarding hobby then ever.

Jim Scala


It's time that I sent you some comments about the Van Slyke Slider 2... although at the time of purchase I was still doing film-based photography, I have since "converted" to CCD imaging with an SBIG USB ST-10E.

My telescope is a custom, home-made 14.5" f/8 Classical Cassegrain sitting on a 12" Schaefer mount. I am shooting around 3000mm of focal length.

The VSS is THE essential tool for this system... finding objects takes minutes instead of hours... with the ability to adjust the viewing port, moreover, the object is almost perfectly centered on the CCD chip when I slide the mirror out. The ability to enjoy the telescope visually without taking everything apart is another huge plus.

Since I am an astrophotographer of very demanding parameters I can only express delight with the dual axis off-axis guiding system installed on the VSS... it is now possible to move the image on the CCD chip and make fine adjustments to the guide star position WITHOUT loosening anything! Although I do rotate the Slider initially to hunt for the best star, once found, all fine tuning is done with the controls... a wonderful system that makes off axis guiding a pleasure and saves untold amounts of time and frustration...

The VSS is built like a tank and is very impressive to look at... guests to the observatory are always taken by the sight of the VSS coupled to the ST-10... it really looks like the ultimate imaging system...

Thank you for creating this accessory... simply put... I can't think of CCD imaging without it.

Tony Hallas, Foresthill (Tony's web site)

This is an addendum to my first report...

The Van Slyke Slider 2 (VSS) has some subtle advantages for CCD imaging that are not immediately apparent... the first being the freedom from filter interactions with the guide star. Quite often, when guiding behind the filters, a guide star will be bright enough for the red and green filters, only to vanish when the blue filter cuts into the light beam. The reason for this is the lack of sensitivity of the CCD in the blue... plus you might have been guiding on a "warm" star. With the VSS this is never a problem since all guiding is done in front of the filters and the guiding continues during all CCD operations.

Secondly, CCD chips being rather small compared to 35mm film, taking two frames to splice together is a common desire. With the VSS, it is often possible to keep the same guide star and perfect orientation of the CCD camera (it does not have to be disturbed to find a guide star)... once the CCD camera has been reoriented via the telescope controls, the same guide star can be recentered by using the pick-off mirror adjustments... this turns a potential nightmare into the simplest of operations. These are two items that I thought potential users might want to know about.


If you don't know who Tony and Daphne Hallas are, you're new to astronomy, or never browsed an issue of Sky & Telescope or Astronomy magazine. Their pictures have graced the pages, and covers, of these magazines for many years. Their efforts are what we all aspire to achieve. Other accomplished astroimagers pale by comparison. To have the world's foremost astroimager use your equipment is the ultimate compliment. - PBVS


I received my Slider 2 and I am very pleased with it! It is a marvelously engineered piece and I have never seen an accessory which is so painstakingly finished to such perfection! I will be using it primarily with my C11, but I also do imaging through refractors. Thanks again.

George Doyle, Kerry, Ireland


Your Mega-Port Sidewinder is beautifully made. This is the first time I've been able to image with the option of using an off-axis guider (critical when using an H-alpha filter) or use the telescope as a visual platform, all without removing a single piece of equipment!! This is critical, as my telescope is pointing with 45 arc-sec accuracy and tracking at f/9 due to the presence of an accurate 350 point T-point model. If I remove any significant item, I might as well toss the T-point model and start over. Now I can go out and just enjoy the view, guide with the internal SBIG 237 CCD or use an off axis guider (the 402 XME), all without removing ANYTHING.

Thanks for making this item. I thought about having something like this, but didn't think I'd be able to make it happen with precision (clearly I was wrong).

Keith Quattrocchi, Lewiston, Maine, www.maineastro.org

Hi Paul,

Your MasterGlide M4 focuser, Versa-Port Slider 2 and accessory adapters arrived this week. I'm not sure what word best described my reaction after unpacking the goods. These pieces are simply incredible from the standpoint of fit, finish and function! The first thing that impressed me was the size of the focuser and slider; compared to my J.. focuser your M4 is truly a Monster. The rigidity of the M4's Crayford bearings are unparalleled when compared to any commercial focuser on the market today and provide rock-solid performance under a heavy imaging train. I tested the focuser/slider assembly in a fully loaded and horizontal position (the harshest possible test) with a dial indicator and was impressed by the absolute rigidity at the far end of the imaging train. The buttery smoothness of the focusing mechanism coupled with the extremely fine finish, craftsmanship and precision positioning of the focuser are truly indicative of world class, professional observatory equipment. Ditto for the Versa-Port Slider; an item guaranteed to satisfy even the toughest critic. I'm really impressed with the exquisite micro-bead finish on the aluminum housings and the anti-reflection coating/finish on the internals. It's obvious that no attention to detail was overlooked.

I'm a degreed Mechanical Engineer and a real perfectionist when it comes to equipment, always tending to look first for the flaws. There was absolutely nothing to criticize on your equipment; it was perfect right out of the box!!! In an era when "real" pride in workmanship has pretty much gone by the wayside in favor of mass production and higher profits, it is truly wonderful to find a company like Van Slyke Engineering holding the line against mediocrity and offering the amateur astronomy community the finest equipment in the best traditions of old-world craftsmanship. My hat is off to you Paul; your work is "collector-class" material that is surely going to be sought after by discriminating astronomers for many years to come.

Best Regards,

Dave Jurasevich, Alhambra, CA

Just wanted to drop you an email to tell you that your suggestion regarding parafocal adjustment on the Hex 1 worked.

Used the turret on my C9.25 mounted on a GM8 last evening. The turret worked flawlessly; it was a complete pleasure to use . I spent much more time viewing,  in that all I had to do was just turn the turret to increase or decrease power instead of removing and replacing eyepieces and refocusing.

I give it the "Six Stars" rating out of a possible Six!

Richard Lipow, Attorney at Law, Malvern, PA

Dear Paul,

Just to say that my MicroGlide Omicron [focuser] arrived. I had to pay import duty and VAT before they would release it. I am delighted with it, a work of supreme beauty and function. Every time I spin the wheel and return to the same "dead on" focus point as recorded on the micrometer head, even with a slider 2, 2" eyepiece, STV guide head and Camera all hanging off the back, it just makes me laugh out loud. When I think I can attach this thing to my TAK FS-60c as well, thus dispensing with a whole mess of extension tubes (each with a different thread) it makes me laugh even louder. Many thanks.

Mike Dury, Bristol, United Kingdom

Hi Paul,

I chose the Van Slyke [MasterGlide M1] focuser because of the workmanship, value and sheer beauty. I do a lot of astrophotography and the precision of your focuser makes focusing much easier. My ota is a C14 Fastar mounted on a Parallax HD150 mount and has digital setting circles. I've been an amateur astronomer since I was 13 years old when I built a 2" refractor. My observatory is on a mountain top in Livingston, Tennessee where there are many clear nights.

Take care,

Robert Shartrand, Livingston, Tennessee

Everyone says that VSI focusers are the best, so I thought I'd start out right with a MasterGlide. Eventually you'll end up with a VSI focuser, so why not just do it right the first time and save yourself a lot of time, frustration and expense.

Christopher Cowan, Camas, WA

Downloaded from the Astrophotography Mailing List (APML)

Over the past couple of years, I've used three off-axis guiders. Each is a very fine unit. The first was the SpectraGuide from S------ A----. The second was the L------ Newtonian Easy Guider. The latest has been the Versa-Port Slider 2 unit from Van Slyke Engineering. Each of these units allow for a radial adjustment of the pick off mirror (prism for the Easy Guider) in a different manner. The SpectraGuide is straight forward - the mirror sits on the end of a stalk, and you push it in and out by adjusting the stalk. The Easy Guider takes a rather interesting approach - the pick off prism stays put and you move the eyepiece tube forward and backward in a direction parallel with the mechanical axis of the focuser. Both of these require you to loosen set screws for the eyepiece tube and move it, which is inconvenient (especially the Easy Guider) when at the scope. So much so that I've never used this feature - I just leave the mirror at the most far away position and rotate the whole unit around in a circle to look for a guide star.

Well, the Slider 2 unit has solved the in-and-out radial search in the way it should be done. It has a tilt-adjustable pick off mirror. This past weekend, I used one, and it is a great pleasure. You put the unit in the focuser, and center the object you want to image. Put an eyepiece in the off-axis tube, and see if a guide star is visible. If not, you can adjust the tilt of the pick off mirror using a small black knob, which effectively allows you to view along the full width of the converging light cone from the primary. Almost always, you can find a guide star somewhere without needing to rotate the whole unit in a circle. In fact, you can usually get the object you are imaging to actually be seen in the guider port. Finally, an off-axis guider you can use to shoot comets at prime focus and guide on the comet's head. And no set screws - the pick-off mirror is spring loaded and stays put wherever you set it with the little black knob. This unit is great. That's an understatement. This unit is GREAT!

The second feature of this fine unit is what it was named for - it has a "flip-mirror" permanently mounted at 45 degrees, but able to slide in-and-out from in front of the camera port, which directs the light up to a 2" port at the top where you can insert a 2" wide field eyepiece for a real good view of what your camera sees. This mirror is the mirror that you would normally flip out of the way, but because it slides to the "left and right" and doesn't flop down, the whole unit can be made smaller providing a much shorter profile than that needed for a full sized 2" flip mirror. Once again, an outstanding feature. And since the box that contains the mirror when slid out of the way extends a good distance in the direction opposite from the off-axis guider port, I had Paul Van Slyke drill and tap a hole in the wall of the box so that a counter weight could be attached. I used a couple of the 2" C-------- counterweights, which provided an adequate counter balancing of my ST-5's head when inserted in the pick-off port. If you want ease of finding a guide star in an off-axis unit, I can whole-heartedly recommend Van Slyke's Slider 2.

Clear skies,

Steve Bell, Littleton, CO


I know of your work since several years, following your constructions in magazines and finding your accessories on the highest range telescopes and instruments, even here in Italy. By myself, I'm the very proud owner of a multi eyepiece VSI turret [HEXAGONAL]. I found it fully consistent with my discriminating needs (I use it to test eyepieces, apart from my personal use).

This idea is coming from having seen the TEC multi eyepiece turret offered at too much high prices in Italy. I think that high quality can be offered, but the price should be the right one. More, some products have reputations that they simply do not deserve, when compared to yours, period.

I think your instruments are the finest crafted ones in these times.

I thank you very much.

Clear Skies

Gianluca, Aleph, Rimini, ITALY


I just wanted to write to tell you how well your MasterGlide focuser (M5A) has worked out since it arrived in Dec.

It has supported every load I've connected and even with the scope literally vertical, didn't budge an inch. The sturdiness, support combined with the precision digital readout was really fantastic. The ability to engage and disengage the Robofocus [motor] in a second in the dark, was a godsend. Needless to say, your focuser worked perfectly with the Robofocus, with extreme repeatability in its movements. (BTW - do you have a recommended set of setting for the Robo such as step size, etc?)

Thanks again for great service and a fantastic product.

Bruce Prager, Piscataway, NJ

Downloaded from the MAPUG Users Group (mapug.com)

I have owned both and also now own a Van Slyke Monster Focuser (now TOADLOADER). Here is my quick review:

The Apogee is smoother than the JMI and has a longer travel (3/4" vs. 1/2" although I've heard that new Apogees have even longer travel). I sold the Apogee and went to the JMI because the JMI was short enough to clear the fork on my 12". With the Apogee, I couldn't look at the zenith. The JMI is a good focuser and, although I have a fetish for quality, I was very happy with it. In other words, although I felt the Apogee was superior, the JMI met my high standards for everyday use.

The Van Slyke is another story. It is expertly machined and over designed in every way. Huge bearings give extremely smooth movement and a full inch of travel. It is short enough to clear the fork if it is not rolled out all the way. Additionally, it has a nice internal compartment for the focal reducer. It does weigh more but with my heavy Meade dew shield, that's actually a bonus. Currently the JMI is on the shelf and after a few more outings with the Van Slyke, it will be sold too.

You can't go wrong with any of these three fine focusers, but if you want the best, consider the Van Slyke.

Jerry Stephenson

Dear Paul,

I have been using the Slider 1 for several weeks now, and I want you to know that it has met and exceeded every expectation.

I am particularly pleased with the feature that allows me to exactly center the cross-hairs of an eyepiece so that they coincide with the center of my CCD frame [VSI's exclusive X-Y axis collimatable top port]. I use an ST-7, which is a rather small chip. In the "old days" before I got my Slider, I would center a reference star by trial and error, and use that star to calibrate my mount for that part of the sky. After that I would take 2-minute exposures of the nearby galaxies, then move on to the next part of the sky. As long as my reference star was relatively near, I could take pictures confident that the galaxies would be properly framed. However, once I moved to a new part of the sky I would need to take several test exposures to center a new star on the frame. Taking these exposures was a hassle. Also, my software (CCD Soft) requires a new dark frame whenever I change exposure length. So after I finally got the new reference star centered I would need a new 2-minute dark frame before I could continue photographing.

All of that is history now. With the Slider 1 adjusted for my telescope, I simply put the reference star I want on the crosshairs, and I _know_ it is where I want it to calibrate my scope to that part of the sky. I take one 2-minute dark frame at the beginning of the evening, and that serves for all night long! (unless the temperature drops significantly, and I can cool the camera down a bit more). When I move to a new part of the sky, just put the star on the crosshairs. No problem! I am spending a lot more time observing, and a lot less time "preparing to observe" thanks to my Van-Slyke Slider!

Setting up a fan near my telescope has greatly reduced the thermal problems I wrote to you about earlier. The all-metal construction of the VanSlyke Slider greatly facilitates the apparatus coming to the ambient temperature. The previous piece of equipment, made out of PVC plastic, served as an insulator to keep heat in, greatly increasing my problems with internal infra-red emissions showing up on my CCD images.

Once again, thanks for a great product!

Pat Madden, Monroe, LA

Hi Paul,

Just got the instruments today. My expectations were high, but nothing could have prepared me for what I found in the box. Simply superb work. I'm a surgeon and I don't give out dexterity-related compliments too frequently, but you're doing a whale of a job.

I'm happy to see the Starlight Express mention on your website. After I've given things a whirl I'll be hammering Terry Platt over in the UK to make sure he gets the word out about the compatability (in fact, "complementarity") of your devices. For the moment his guide camera's on back order in the US, unfortunately.

All the best,

Craig A. Miller, M.D.

Chief, Division of Vascular Surgery

Director, Angio-Vascular Laboratory

Department of Surgery, St Joseph Hospital

Dear PVS,

I have received the MGF1 (now Epsilon) and associated docking rings here in Hamburg/Germany two weeks after my order and I want to give you some feedback.

Your MicroGlide focuser is indeed a marvel of engineering art and it functions every bit as smooth as you describe it. I am glad I ordered one and I'm only sorry that I didn't do so earlier.

But in any case, what matters for me now is that I finally do own one of your legendary focusers!

Thanks and cordial greetings!

K. Peter Schüler, Hamburg, Germany


Just some feedback that might be useful regarding your new MicroGlide Coupling Focuser. The threaded end of the MGFCO is just small enough to fit inside the standard TAK Focuser assembly. Therefore, once mounted, max effective length is only 2". If you subtract the length of the standard tak adapters to reach 2 inches, and add the adapters that can now be threaded to your 72mm end, the max effective length (profile) drops down to 1" or less.

Thought you might find the numbers interesting.

Bruce Prager, Piscataway, NJ

A focuser that only consumes 1-inch of relative profile - WHOA! - PBVS

Hi Paul,

The new focuser (MicroGlide Epsilon focuser) is a real dream.

Again great focuser!

Tom Porter, Peyton, Colorado

(see "User Installations" link for pictures of Tom's Televue 101 piggyback installation)

Dear Mr. Van Slyke

Received my order a few weeks ago but the skies have been overcast & cloudy. Your workmanship is evident right out of the box! Finally got the chance to use the MasterGlide focuser (M3) on my 12" LX200 the other nite and I'm totally blown away!!! It's everything your advert says; silky smooth, rock solid, easy to operate, visually discernable in the dark (unlike other all-black units). Now, I'm just a rank amateur/beginner but it was obvious even to me that your design enbles ALL the light gathered in the sight tube of the telescope to reach the diagonal as opposed to the restricted view effected by the JMI unit that came with my scope. The net result is like adding inches to the effective light gathering capability of the scope. The enhanced viewing is simply astounding!!!!

When I'm ready to advance to imaging I will most assuredly be contacting you for a "slider."

I am also self-employed (hotel owner) and I enjoy and understand your independent approach and comittment to your business. The quality of your product and your willingness to "sign" it says it all.


Terry Bailley, Canada


Had a chat with my father-in-law over dinner while checking out the new (MasterGlide M1) focuser (made his top line J-- focuser look wimpy). We had a look at the bent screw and both of us can not see how it could have got bent (it looks pretty strong so it would take a bit of a wack to bend it) without there being any other damage to the focuser.

More importantly from a design point of view, we also do not see a point of it being there in the first place. What is its purpose? It appears to push the main tube AWAY from the four bearings (it lies between them). This does not seem to be a good idea. Maybe it could be removed from the improved design?

What do you think?


Steve Ryde, Australia

Steve was referring to the moving tube, lock-down thumb screw on the focuser's outer housing. We are still trying to figure out how it got bent in transport, because it's a chrome steel knurled thumb screw (of course, I sent him a new one). His other suggestion was taken to heart, too. In future production runs, the lock-down thumb screws were moved to the other side of the focuser housing to apply force AGAINST the four Crayford bearing instead of AWAY from them. Good idea, Steve! And thanks! - PBVS


Thanks for the response. Yes, I do have your Monster focuser (now TOADLOADER). It is the only one that I know of that is capable of handling the large load I have on it. The J-- focuser was completely inadequate. However, they were good guys and let me return it.

Your suggestions sound good and I will check them out.


E. C. Welch, Yakima, WA

Hi Paul,

Thanks for doing a great job on the secondary holder! I tell everyone I know about your quality workmanship. I'll probably plan on doing the same (getting one of your secondary holders) for the 16 inch Ritchey later in the year. And definitely a "Super Power Focuser."

Thanks again Paul!

Brad Ehrhorn , Incline Village, NV

I am happy to find someone who makes professional looking equipment. Unfortunately, I tried T----- who makes real junk. I tried H------ who tries but has rather primitive designs and is not cheap either.

I am now in the process of working up some needs for a small observatory which I built and donated to the Madison Astronomical Society late last year. I will certainly give your equipment a try when I get the details of our needs worked out.


Prof. R. A. Greiner, Madison, WI


I have had the opportunity to work with the Slider 2 and become intimately familiar with its operation. Everything is performing beyond my original expectations. I have used the Slider for Lunar and Deep Sky imaging -- both with great success. The helical adapter is a great addition to the Slider and has performed extremely well. Using a 4.8 mm Nagler in the viewing port, I am able to get very close to perfect focus, every time. Sometimes I hit it right on the mark. (Since I make my final focusing adjustments with the aid of a dial indicator, I am able to determine perfect focus for any given night. Last night I focused the Astro-Physics refractor using the Nagler and the viewing port -- I tried to improve upon it but could not.) This accuracy is great for those "No time to focus - Gotta get the image NOW" situations.

In addition to that, I have used the helical adapter as a focusing aid when I insert filters into the light path. I simply note where the helical adapter and Nagler are in focus with and without filters. When switching, I make the appropriate rotation to the helical adapter. Easy. (I could continue to heap tons of accolades upon the Slider, but I doubt that they would describe how great your stuff is -- and they might just cause you to raise your prices!)

BTW, your imaging primer is very good as well as all of the additions that you made to your web site. How DO you find the time!?


Gregory Terrance, http://www.frontiernet.net/~gregoryt

Dear Paul,

Thanks for the recent information on micrometer travel distance. It was just what I needed and when I needed it. I am very pleased with the bifilar optical micrometer, although I had to design counter weights in both the R.A. and dec. axis of my C8.


Bill Davis, Metairie, LA

I have, within the hour received my Slider. Thank you so much for making a custom version for me. It is beautiful. Everything I had hoped for. I can place you among the equipment persons I trust to make wonderful things.

Great job!

R. A. Greiner, Emeritus Professor of  Electrical and Computer Engineering, Madison, WI

Hi Paul,

In order to secure a guide scope so that it's not a problem, you do need reasonably expensive components, like the L------- plates and rings. This can easily costs a few hundred dollars. The usual advice to overcome flexure is to forget about using a guide scope and do off-axis guiding. But it can be frustrating finding a sufficiently bright enough guide star while maintaining the object your imaging to be at least close to the center of the frame. And with the small size of most CCD chips, it's even worse. But, there are off-axis guider (OAG) units (Sliders and Sidewinders)that are available for around $500 (an amount that you could easily spend on a guide scope setup) from Van Slyke Engineering that use tilt-adjustable pickoff mirrors, which provide a greater range of guide star selection than the usual units with fixed-angle pickoff mirrors or prisms. These units make off-axis guiding about as easy as using a guide scope.

All I can say is that the advice regarding flexure from the experienced experts turned out to be true for me. But knowing it didn't stop me from trying a guide scope, which even though didn't work out, was none-the-less fun. I wish I would have gone the OAG route sooner, though - I could have bought a couple of Van Slyke units with the money I've spent on guide scopes.

Clear skies,

Steve Bell, Littleton, CO, email: sb635@delphi.com, Astrophoto page: http://people.delphi.com/sb635

P.S. I can't remember if I thanked you for sending me the two C-------- weights at no charge. They work great. When they are attached, they counter balance my ST-5 so well that I can very easily rotate the whole unit (Slider 2) around in my focuser. There really is no need for some type of motor driven rotation unit - rotating by hand is plenty good enough. Once again, thanks.

I had no idea of the quality from the pictures. It’s [Versa-Port Flipper DFM] built like a tank!

John Jacobson, Portland, OR

Now where have I heard that before? - PBVS

Mr. Van Slyke,

I currently own one of your Versa-Port Flipper 2s, and am very pleased with this unit. By the way, I purchased a set of imaging filters and they fit the filter slot perfectly.

I would like to find out if you could make an adapter and if so what the approximate cost would be? What I want is the rear primary imaging port with the filter slot connected directly to the front input port with the Schmidt-Cassegrain adapter. In other words, a short, straight through, two inch tube with the filter slot in or around the middle, an SC adapter on one end and two inch accessory adapter on the other end. Essentially removing the flip mirror, secondary port portion of your Versa-Port.

Thank you, I look forward to your reply.

Cal Sandfort, Boise, ID

This was such a good idea that VSI now manufactures and markets these inexpensive drop-in single filter adapters (item# FSAT). Keep 'em coming! - PBVS

I originally had (and still do - any buyers out there at $220) the very nicely made (and small [short] 1.25 " system) H------ FMB system. However, I have always acquired only 2" filters and was determined to keep trying to find an affordable 2" system that had a method to easily change filters so I could start Tri Color imaging. The Van Slyke is about the only "quality" game in town. I love it!

Best regards,

Frank Loch, Try Deep Space 99 at http://www.early.com/~floch/index.html

Hello Paul,

I for one have always steered people to your products. I know Quality when I see it. Paul, yours is THE BEST product out there and that is thirty years in the hobby speaking.


Danny E. Darlington

Downloaded from the SBIG Users Group

<SNIP> BTW, I just purchased a Versa Port Micro-Slider 1 from Paul Van Slyke. It is a work of art and it makes using the ST7 a piece of cake. It now takes me a few minutes to obtain and focus on an object when it sometimes could take over an hour. It has a smaller profile then the mirror diag and the visual back that came with the scope, alleviating the problems that one might have with back-focus. I had to attach an FSA (Filter Slot Adapter) since the Slider is so close to my focuser I could not use my digital micrometer focuser without it. Even with the FSA I still have a shorter profile then using the original set up that came with my scope.

Now if only Paul would ship my Stray Light Blocking Ring for my FSA that he forgot to include. (Are you reading this Paul) ;->,

Elliot Romero, Suffern, NY

I read and obeyed post haste. - PBVS


Thanks. The Micro-Slider 2 is a pleasure to use. It really makes life easier. I've only used it with a CCD (micro-slider 1 mode), but I am sure it works great with a camera too.

Clear skies.

Steve Leikind, St. Paul, MN

Today I rec'd my Versa-Port [Flipper 3], 3 days earlier than I expected! Imagine my joy. In addition, I have spent the last hour examining it and the accessories, and wanted to tell you as quickly as possible that it is a work of art and I can't wait to get home and hook it up. Craftspeople like you are a clear indication that quality and pride of workmanship are still alive and well in America. Thanks for the speedy service and I'll e-mail some pictures soon.

Don Stanford, West Greenwich, RI

Well Don, I don't know about that? I think quality & pride of workmanship in America are sickly and near dead, myself. There are just a few "weird people" like me around who make it seem like these lost American attributes are "still kicking." - PVS

I just received the shipment of items [Electro-Port 1, Slider 2, Micro-Slider 2, Micro-Gage Focuser 2, Digital Super Power Focuser, DC Servo, etc., etc.] yesterday. I must say that the quality of your products is excellent. I have been involved with astronomy for over thirty years and have owned just about every telescope and accessory known to man, but your products are a cut above.

Joe Vallee, Woodbury, NJ


I just received the HEXDC  [DC Servo Hexagonal] this afternoon. This is by far the finest piece of astronomical equipment I have owned. The workmanship has to be seen to be believed. What surprised me the most was the two pittman motors. They are the same ones that power my Meade 16 inch LX-200. In reading the instructions you mentioned something about a 2 inch focuser. Do you feel the SPF or the MFG-2 can handle the weight of the HEXDC? I have several counterweights so balance is not a problem. Let me know what you think. Again the HEXDC was well worth the wait. The engineering reminds me of my Questar 3.25 inch telescope. Hope to hear from you soon.


Joe Vallee, Woodbury, NJ

Is the Meade/VSI connection, referring to the Pittman motors, good for VSI's reputation or not? You tell me.

Oh yes! The patented MGF2 (now Omicron), and especially the Gliders, can handle any load you can throw at them, and then some. - PBVS


The RFT (Rick-Field Telescope) arrived yesterday. I'm absolutely amazed. It's better than I ever expected or hoped for. In a world of homogenized junk, you've created a first class, distinctive instrument at a not un-reasonable cost. Your skill and craftsmanship are evident and certainly appreciated. Thank you Paul.


Chris Brown, Charlotte, NC

Hi Paul,

The package arrived today. WOW!!! You really turn out nice work [VP Slider 1] and so light too. I showed it to our Technology and Applied Studies people who run our CNC lathe. They were very impressed. Quality always demands (and gets) attention. Thanks again and good luck with the Newt focuser. Keep in touch.


Steve Ryde, Sydney, Australia


The new ZPTA arrived yesterday -- an OBVIOUSLY better design!!! Thank you again for treating your customers the way you would like to be treated. That really is refreshing! And it leads to better products!

With Highest Regards,

David Lakey

Web: http://www.mindspring.com/~dlakey

Astrophotography: http://www.mindspring.com/~dlakey/astro.html


Received the SC Focuser (MasterGlide) last week - customs are a little slow over here!

As an engineer I must admit that the quality of your product is exceptional. In my opinion it is the most professionally made piece of equipment I have obtained or used on a telescope, and is beyond much of the equipment used on modern helicopters. I am very happy indeed with the focuser and look forward to using more of your designs. It is also refreshing to finally obtain a product that actually matches the associated advertising hype!!

Many Thanks & Clear Skies

Peter Gregory, Bristow Helicopters, Karratha Airport, Australia


Words cannot express the *value* in the M2! The Quality is more than obvious. Your dedication to detail and workmanship are simply the best. I now would like a recommendation on a Versa-Port. I will be purchasing a SBIG, most likely the ST8E, with an AO-7, and will be using the Meade F/6.3 and Optec .5 widefield focal reducers on either a C11 which I now own or a 12.5" Ritchey-Chretien I am *wishing* for. I'll call early next week, Monday to discuss your recommendations. Qualtiy is often hard to describe, but is easily identified when seen and *felt*. Your Crayford focuser is just simply awesome!


Tom Papa, Mobile, AL

Dear Paul;

Received the Monster focuser (now TOADLOADER) and adapter yesterday and of course I do not have to tell you how impressive the workmanship is on this equipment. What I do wish to tell you is that when I placed the adapter on to the Astro Physics 130 mm f/6 the fit was perfect. Then placing the Monster on to that was very easy and also a perfect fit.

To my surprise, after a rough focus with the rack and pinion gear on the AP and locking that in place with AP's locking screw the images were now in the hands of the VSI Monster. I was totally shocked...the stars were pin point, the focuser gave me a clarity of image never seen before. Polar alignment with the ASP GTO mount was much improved for when you centered your star with the Monster, boy you were rock steady and centered!

I viewed last night mostly open clusters and with the clarity and control this focuser gave the Astro Physics scope was really at it's peak performance.

Paul, thanks for developing a product that is highly professional and can be in the hands of the amateur.

Howard Lazarus, Boynton Beach, FL


By the way, the M1 works just fine. Nobody in my club has ever seen such a thing of this level of beauty and functionality in a focuser. The M2 blew them away by it's awesome girth and smooth operation. Manual focusing is a dream with this focuser.

Russell Shettle, Bethesda, MD

Hi Paul,

The Monster Focuser (now TOADLOADER) and other accessories finally arrived just before Christmas. All seem in fine condition. Won't bore you with why the long delay getting here. So far just this observation to make. Your product is very, very impressive. Better than I had anticipated and I had anticipated a lot.

Thank you.

Warm regards to you and yours for 2000.

John Upton, Australia


NCF2 arrived safety today; simply superb. Thank you.

Andrew Hooper, Nottingham, England


It's again me. The NGF J-- is a terrible thing: it can't support even a lightweight camera (650 gr) and the digital indicator is very imprecise.

First to tell you how lucky I am with your Versa-Port Slider and your Micro-Gage Focuser (old MicroGlide).

Everybody of my friends is very impressed by your engineering. We are using your focusers for a C8 and C11. Problems arise with the Tele---

refractor GENESIS.

Thanks for your great help.

U. Wiggli, Switzerland

I don't know if WOW covers it. My name is James Cackette and I had the privilege of purchasing one of your fine focusers. Keeping it short and sweet your focuser performed flawlessly and then some in the dead of winter with everything from video cameras to 35 mm still cameras. Absolutely wicked piece of deep-sky hardware!!!! Thanx a million once again. I definitely will be visiting you again for more gear.

clear skies, James Cackette, Whitehose Yukon, Canada

Dear Mr. Van Slyke,

I received the [custom] focuser you made for me sometime in October 1999, yes, it was the last century (You may recall it was for the 80's model Astro-Physics 6" refractor. My apologies for not being able to contact you till now, to tell you that your work and the lens itself are probably the two finest pieces of work of any kind I have in my possession. Thank you for working with me to deliver this fine product. I actually had my first chance to use it on Sunday, 20 February, for the first time. It is a beautiful instrument.

Thanks again.

Mike Madsen, Altadena, CA


My Versa Port Slider 2 and related accessories arrived just a few minutes ago. As always the equipment is beautiful!!! It is obvious when I see the workmanship that I am dealing with someone who takes great pride in their work! I can hardly wait to try this out. Now if I can just get some clear sky for a few minutes. In this neck of the woods it has been raining for what seems like 2 months. So most of us have been too busy building an ARK instead of playing with our scopes.

Thanks again...best regards,

Warren Stallings,  Pittsburgh, CA

Dear Paul,

I received my Versa Port and accessories today (Monday) after placing my order on Friday. I just wanted you to know that I am extremely pleased with the service. I also wanted to thank you for not charging my card the full amount of $1300.00... I fully expected you to and that would have been just fine. It just goes to show that you are not only a true professional but a real gentlemen as well. The Versa-Port is a masterpiece... a true work of art, Paul. Thank you very much and I look forward to receiving the focuser in a couple of months.


Doug LePage, Miami, FL


Sorry about your falling out with S&T. At least amateurs around here are beginning to know your work through me. I'm talking about the "Monster Focuser 1" (now TOADLOADER) you recently sold me. You should see how it looks on my beautiful Classic Orange Tube C-14. Yes, I recently acquired an old fork mounted C-14 in "MINT" condition and I love the beast! Great scope with great clean and well cared for optics! and now, with the addition of your Monster Focuser, it's become a highly talked about system by all who are in my club. So far at least a dozen amateurs have experienced the silky smooth feel of your focuser on this scope. Most of them were only vaguely aware of the name, "Paul Van Slyke" but now they are hands-on familiar with the product that's behind the name. I wish I could convey to you all the comments I've herd about this focuser in the way they were expressed to me.

Thanks for such a great, beautifully designed product Paul... You've made the Crowning for the Grand Daddy of the Celestron Schmidts!

Russ Shettle, Bethesda, MD

Dear Friend,

I have received my bifilar micrometer. What a gem! Truly this is a work of art along with being a scientific instrument. I thank you ever so much.

Clarence Stevens, Tacoma, WA


My new Slider 1 just arrived. You are absolutely incredible! I love the improvements you've come up with (compared to my older Slider 2, which is also a wonderful instrument). The slip ring coupling is great, and the operation of the slide itself is silky smooth. I love it!

Many thanks,

Larry Denmark, Hollis, NH

I received the Versa-Port Slider 2 with accessories and it's everything you say it is! It is elegant in form, classic in design, outstanding in function, and, operationally, the epitome of simplicity! Appearance-wise, it more properly belongs in the living room, with a velvet setting in the middle of an antique rosewood table, rather than sticking out the back end of a telescope on a dark night! I am more than satisfied and simply a "delighted" customer!

Again, Paul, Many thanks for the Versa-Port Slider 2 and a "delightful" customer experience. As a design engineer in an earlier lifetime, I have a great appreciation for what was involved in the Slider 2's conception and execution.

Many thanks!

Jack Fooks, McMurray, PA

Hi Paul,

I received my Slider 2, Monster 4 focuser (now TOADLOADER) and accessories yesterday. I am simply delighted. EXCELLENT WORK!

Thanks again!

Steven Novosel, Vacaville, CA


I just retrieved my package from the post office this morning and all is well. In fact, I feel it belongs in an industrial museum, as everything is so beautiful. I installed the focuser, the filter slide and the mirror Slider 2 on my 12 inch LX200 in my observatory and it is rock solid. It only adds about 1-1/2 inches to my optical path compared to my prior arrangement (visual back reducer, skylight filter, and Meade 2 inch diagonal). I had previously removed a J-- focuser and Meade large box of mirrors as being too squirrelly. This adds 2 inch filter capability (needed with my ST1001E) and I can still use my Robofocus software and autofocus.

Thanks for great products.

Robert Pitt

Professor of Civil and Environmental Engineering

University of Alabama, Tuscaloosa, AL

Hello Paul,

Some days ago, I have got your Monster Focuser 3 (now TOADLOADER). And what could I say now? It is very great, very good, very excellent and the best I've ever seen.

The precision of all parts and the motor-installation for ROBO-Focus are perfect. By the way: Also the order, the payment, the delivery time an the package are perfect. Thank you very much. Now I'm thinking about it, why most german Astronomers do not know your products. (I am sorry about my bad english, but I think you know what I mean).

Thank you for your answer and your great Monster-Focuser. Now I have fun to observe objects in the sky...

Clear skies from Germany.

Arno Losert, Observatory Frankfurt/M.


Today I received my 25mm illuminated reticle eyepiece (one day earlier than suggested). I felt it appropriate to send you a line to thank you, not only for the prompt shipment, but also for providing a product of a quality that should set a benchmark for the industry. I have almost every illuminated reticle eyepiece that is commercially available. However, I have not been satisfied with any of them until this purchase from VSI. This multipurpose eyepiece will not only be excellent for use in my guide scope for astro-photography, but also would/will be an excellent wide-field eyepiece for my finder scope. The design and quality of the machining of this piece put the available eyepieces to shame.

Thank You Sir for this excellent product.

Sincerely, Chuck Morris, Chicago, IL

I saw a great bumper sticker the other day, "Save the Planet, kill yourself." - PBVS

I saw another great bumper sticker, "Save the People, kill an environmentalist." - PBVS (ain't freedom wonderful!)

This unbiased user comments web page is a neutral open forum established to help interested people make the right purchase decision based on amateur and professional astronomer's previous experience with Van Slyke Engineering and other manufacturer's similar products. The above reprints are solely the viewpoints, experiences, comments and/or personal opinions of the person [or persons] who created the letter. VS Engr assumes no responsibility, or any liability for the content of the above letters. VSI does not support or deny any of the above comments, whatsoever. VSI does not solicite input, but if you would like to participate in this written forum [pro or con] about VSI or other related astronomical products, you can e-mail (click on E-MAIL bullet above) or snail mail pertinent information to the address listed at this web site. Business names will be omitted for liability reasons.

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