Tom Osypowski: Mastering dobsonian tracking hardware for stargazers

Tom Osypowski has significantly impacted the world of Dobsonian telescope tracking through his innovative Equatorial Platforms. In his journey from building his first platform in 1984 to developing cutting-edge designs today, Osypowski has transformed how Dobsonian telescopes are used for both visual observation and astrophotography. His story is not just about crafting practical tracking solutions but also about pioneering techniques that made large-aperture telescopes more accessible and functional for amateur astronomers.

Tom Osypowski: Mastering dobsonian tracking hardware for stargazers

Below, Osypowski shares insights into his early inspirations, the challenges he faced, and how the Dobsonian revolution influenced his approach. He delves into the technical aspects of designing and building tracking platforms, the evolution of materials and motor systems, and how he tailored each unit to individual users' needs. From his first builds to modern, durable aluminum models, Osypowski’s dedication to quality and innovation has helped over 700 platforms find their way into the hands of enthusiastic stargazers.

ScopeTrader: What inspired you to build your first Equatorial Platform in 1984, and how did the "Dobsonian revolution" influence your decision?

Osypowski: I built my first Equatorial Platform back in 1984. This was the period of the "Dobsonian revolution," when the concept of large aperture combined with simple-to-build alt/az telescopes was taking the amateur astronomy world by storm. I built my own Dob, a 16" f5, in 1983 and immediately recognized the need for some kind of tracking to be able to fully use the capabilities of such a fine instrument. A few years earlier, news had developed about just such a tracking system that was ideal for these new alt/az scopes. First, Adrien Poncet in France had designed a device he called an Equatorial Table that would give a Dobsonian telescope motorized tracking for an hour or so. His design was modified/improved by other pioneers like Alan Gee and Georges d'Autume. A fine article in the 9/1988 issue of Sky and Telescope details these early efforts.

Anyway, as soon as I became aware of these ideas and designs, I immediately modified the groundboard of my 16" Dob into my first Equatorial Platform. Voila, I had tracking! Showing the scope with its Platform at the 1984 RTMC garnered a lot of interest and one of the Merit Awards. Other Dob owners began asking me if I could build them such a Platform. Well, from that seed my business, Equatorial Platforms, was born.

ScopeTrader: Can you walk us through the process of designing and constructing an Equatorial Platform today compared to your early builds?

Osypowski: Early on there was a lot of experimentation with motors, drive design, overall Platform design, etc. Eventually, I settled on the VNS (vertical north sector) design of Platform and made some adjustable jigs for cutting the critical curved surfaces. After building hundreds of Platforms I still use the same jigs today. They are simple to adjust and set up using numerous clamps, and they are used with all size Platforms and all latitudes. The actual cutting of the metal is done with a jigsaw and then tuned up to perfection with a couple of routers.

ScopeTrader: What are the biggest technical challenges in creating a high-quality tracking platform for Dobsonian telescopes?

Osypowski: One challenge for people taking on the building of a tracking Platform is figuring the layout of the tracking sectors and the curves that they need. If one reads some of the directions online for calculating these curves, it quickly becomes apparent that a proficiency in algebra and trig would be necessary to follow those directions. Nothing wrong with that approach if one has the aptitude for the math. I didn't, so I developed a step-by-step construction technique that involves measuring as one goes along, using simple rulers and angle finders. It's a process that took a lot of iterations to perfect, but now it has become second nature for me. It also really helps to have notes from all the previous Platforms to refer to.

Once the rough Platform is precisely attached to my cutting jig, using simple measurements and the aforementioned clamps, it is rotated around on its polar axis and the critical curves in the plates are cut automatically by two different routers.

Equatorial Platforms Enable Precision Tracking for Dobsonian Telescopes

ScopeTrader: Your company now offers a buyback and refurbishment service for used Platforms. What prompted this initiative, and what goes into restoring an older unit?

Osypowski: Past customers were writing to me about their unused Platforms, wanting to find new homes for them. On a case-by-case basis, I asked about their Platforms -- what condition they were in, if they were working, were there lost or broken parts. Mostly, I wanted old Dual-axis models, wooden or Aluminum. Also they sent pictures to give me clues as to what might be needed to be replaced or fixed. I would offer them a buy-back price and, if accepted, they sent the Platforms to me for refurbishing and reselling. Hence I have a used/demo Platform page on my website.

Generally, the Platforms are disassembled, parts cleaned and lubed as required, and then they are reassembled with new motors/bearings as needed. As with our new Platforms, the renovated Platforms are star tested with a telescope, the drive rate is tuned in, and the slew controls are also tested. Once everything is calibrated and I am satisfied with their performance, the used Platforms are posted for sale. They generally go quickly as the pricing is 70% or less of a new one.

ScopeTrader: How do Equatorial Platforms enhance astrophotography capabilities for Dobsonian users, and what limitations should users be aware of?

Osypowski: A properly constructed Equatorial Platform with the right controls can give any Dobsonian telescope imaging capability. This can easily been seen on our website with numerous pages devoted to imaging with a Dob, such as https://www.equatorialplatforms.com/image.of.month.shtml. However, even today I read of or hear comments like, "Dobsonians are alt/az and so cannot track or image to any extent." These days, tracking for a Dob is easily achieved, with the proliferation of alt/az tracking mounts and Equatorial Platforms. Great images can be achieved with either type of mount. The alt/az mount, of course, will be limited to shorter exposures (10-20 seconds, typically), but stacking a bunch of those is a very effective technique to get a full image. With the Platform, one can do the same, but longer exposures are also possible because there is no field rotation. With an auto-guider, one- to five-minute (or more) exposures are doable.

Besides tracking, the other control feature needed for imaging is good motorized slew controls for centering images on a CCD chip or laptop screen. It is difficult and frustrating to try doing these tasks by just moving the scope by hand. For a Platform, the RA slew is obvious - you just slightly speed up or slow down the tracking rate. But slewing in a Declination direction (i.e., perpendicular to the RA movement) with a Platform is not so obvious. Various solutions have been utilized. Motorizing one end of the Platform (North end or South end) and slowly lifting it up and down is one method. However, this type of slew movement will also affect the polar alignment. Not ideal. The solution I have come up with is to raise or lower the telescope itself that sits on the Platform. This gives a good DEC motion for a large part of the sky without altering the polar alignment.

This brings up one of the limitations of an Equatorial Platform: the DEC slew breaks down in certain parts of the sky and becomes almost identical to the RA movement instead of being orthogonal to it. Low in the Northeast and Northwest are such areas. But along and on the other sides of the meridian, when objects are at their highest -- that is the best area of the sky for the DEC axis to shine.

Another limitation, of course, is the finite tracking time of the Platform before it has to be reset for a new tracking run. With my Platforms, I generally shoot for providing an 80-minute run. One can do a lot of visual observing or imaging work in 80 minutes, and then a quick pull of a handle gives you another 80 minutes...

Astrophotography with Equatorial Platforms: Real results from the field

IC342 The Hidden Galaxy (Top Left), M1 2X2 Binning (Top Right), M8 by Marcus Hagi (Bottom Left), M13 Globular Cluster 15 seconds, low gain, 2x2 Binning 9Bottom Right)

ScopeTrader: Over 40 years, you’ve delivered more than 700 Platforms - do you have any particularly memorable projects or customer stories that stand out?

Osypowski: Actually, we have a long list of customers who have written us with their stories and experiences with their Platforms. Some have also sent pictures of their setups and images taken with their Dobs on the Platforms. Many of these comments can be seen here:

• Customer Comment of the Month
• Owners Speak Out
   

Typical entries include:

Customer 1:

"The platform you built me arrived many weeks ago, along with many weeks of rain. I tried it out last night. All I can say is, WOW. I am a nut for high quality anything, and your platform is on my 'best of' list. Saturn at 3:00 a.m. looked like it was tacked up on a bulletin board. I pulled up a chair, was mesmerized, and it didn't move. AT ALL. The platform raised the bar on my favorite pastimes sky high. Thanks man. I'm having a blast!!"

Customer 2:

"Tom - I tried out the platform last night for the first time at a star party. It was incredible! After eyeballing the polar alignment with Polaris, it tracked my 17 1/2" Dob flawlessly. The platform is rock solid and a piece of real craftsmanship. The dual axis panning hand controller was wonderful as I panned up and down the sinews of the Veil nebula at 200x. Everyone around me was blown away by the smoothness and dead center accuracy of the tracking. I am one happy camper. Thanks!"

Customer 3:

"Hi Tom, The platform arrived yesterday. It looks great, setup was a snap, and the customizations for the Lightbridge are spot-on. Even better, the weather cooperated just enough to take it out for a trial run. I just pointed the platform roughly north, leveled it out, and set the telescope on it, turned it on and I was tracking. Wow! What a wonderful experience to center the Double-Double at 315X and have it just stand there in the field of view. Walk away from the scope for 15 minutes, come back, and the image is still perfectly centered. The platform is going to make a huge difference in the quality of my observing. Thanks for a great product! I've had a couple more nights out with the platform. In particular, I got out the other evening to look for the supernova in M51. The platform allowed me to spend the time relaxing and viewing instead of chasing. As a result, I was able to see knotty detail in the galaxy I have not seen before as well as the supernova as it slipped in and out of view. An awe-inspiring scene. It really is true that using the platform is like adding a couple inches of aperture."

Customer 4:

"I got to use the platform with my 20" Obsession at the Seneca Shadows campground this weekend. This site is 21 miles from Spruce Knob, which is - arguably - the best dark sky site in WV. And it was the new moon. And as it would happen, my Son's BSA troop was camping near there at Seneca Shadows so ... I put up the scope and we started out with M13. Having been Platform-less since November I have gotten used to observing sessions with the scouts going something like this: Aim at object, check in low power EP, run down ladder, get one maybe 2-3 kids up to see object before one says "I don't see anything", run up ladder, recenter ... repeat.

Friday was different.

I switched on the platform and set it. I aimed at M13. I checked in the EP. I told the kids to first look in the finder (80mm Orion Short Tube mounted on the UTA) and then in the telescope's EP. One scout goes up the ladder, then another, then another, then a leader, then a mother, then a scout ... I begin to wonder what they are looking at. I keep thinking I must go check in the EP but the line is long and I hate to interrupt. Only by watching the kids and listening when they look in the EP could I reassure myself that it was tracking. The response was the same. Look in the finder ... do you see it ... fuzzy yes good ... now look in the EP ... "WOW". This happened again and again and again. Finally I could stand it no longer, I butted in line (well it is my scope), ran up the ladder ... "WOW" ... there it was M13 - still in the EP. Thanks. Platform works great."

ScopeTrader: What improvements in materials, motors, or software have had the biggest impact on the performance and durability of your Platforms?

Osypowski: The biggest improvement in performance and durability came when I developed my line of all-metal Platforms back at the turn of the century. Using a light-weight but extremely stiff and sturdy welded aluminum structure for the Platform frame proved to be a game-changer. The Aluminum Platforms have proved to be lighter than the wooden models, more accurate in tracking, and definitely more durable with their beautiful powdercoated finish. For years I offered both wood and metal Platforms to my customers, but now I have simplified production and tooling by just listing the superior Aluminum models.

Over the years I have been fortunate to have available the services of some other small astronomy-related companies that have produced parts for my Platforms, notably custom stepper motor drives with slew controls.  Also, local fabricating shops have helped out with production machining of various drive components. If I can't make certain components "in house," I find the best people I can to do the job for me. My goal is always quality, in components, fabrication, and finishes.

Images and experiences with Equatorial Platforms

Moon and Jupiter (Top Left), Plato and Alpine Valley (Bottom Left), NGC 6946 The Firework Galaxy (Right)

ScopeTrader: How do you tailor each Platform to an individual customer's needs, and what factors should a buyer consider when ordering one?

Osypowski: Each of my Platforms is custom designed to work optimally with the buyer's particular telescope and for the latitude of their principal observing site. First consideration is the telescope itself. Some Dobs (such as the Obsession-type scopes) work well with the Platforms by using the top of the Platform as a new groundboard for the rocker box. One just removes the stock groundboard and puts the rocker box directly on the Platform. There is a center pin and three Teflon pads for the box to sit on and revolve around. This arrangement makes the Platform a motorized groundboard and keeps everything as low and stable as possible.

For the imported Dobs (like those from Celestron, Sky Watcher, Lightbridge, etc.) with the large round bases, it is not practical or necessary to remove the groundboard. These Dobs typically have three small "feet" or pegs that sit on the ground. So I manufacture three little "cups" that are attached to the top of the Platform. The feet of the scope's groundboard then sit in those cups and keep the scope from sliding off the Platform as it tilts through the tracking run. In this case, no modification of the scope is required to use it with the Platform.

When ordering a Platform, discussion of latitude is always important, as each of the Platforms is built for a specific latitude when leveled on the ground. Usually, this "nominal" latitude is for the principal observing site that the Platform will be used at. However, by tilting the Platform when setting it up, it can be used at different latitudes. If one is North of the nominal latitude, then tilt up the North end. If one is South, then tilt up the South end. This tilt adjusts the polar axis of the Platform, just like any other equatorial mount. How far one can go with this latitude adjustment depends on how much tilt the telescope can take before becoming unstable. I usually recommend a maximum of +/- 5 degrees tilt. So, a Platform built for 35 degrees latitude could be used from 30-40 degrees without affecting the quality of the tracking.

Other considerations when ordering include custom modifications for those buyers who want to use their Platform with multiple telescopes. Each scope might require a different method of securing it to the top of the Platform. Also to be factored in is the type of observing the customer is contemplating. For pure visual observing, the Single-axis Platforms are all that are needed. For imagers, the Dual-axis models are required in order to get the slew controls needed for centering objects on the CCD chip and/or the laptop screen and for autoguiding.

ScopeTrader: What do you think the future holds for Equatorial Platforms and Dobsonian tracking technology in general? Any exciting developments in the works?

Osypowski: As I mentioned earlier, Dobsonian tracking technology got started some 45 years ago with the invention and development of the Equatorial Platform. Decades later, computer and encoder technology reached a point where it became possible to motorize the altitude and azimuth axes of a Dobsonian and achieve tracking in that manner. Both of these methods are still alive and well today, though the latter technology is the more prevalent in today's commercial alt/az telescopes.

Still, there will always be room for EQ Platforms. There is something satisfying that appeals to many Dobsonian users -- the ability to grab the scope and move it around by hand, quickly pointing it at any desired target in the sky and observing without having to push buttons and stare at readouts on a screen. That's the beauty of the original Dobsonian vision. An Equatorial Platform doesn't detract from that simplicity. What a Platform has always added, though, is the game-changing advantage of motorized equatorial tracking for high-power visual observing, group viewing, and astro-imaging without field rotation. A Dobsonian Telescope on an Equatorial Platform is a complete observing machine, as hundreds of our customers have attested to.

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