Yuri Petrunin: The man behind TEC Telescopes

When you sit down with Yuri Petrunin, founder of Telescope Engineering Company, the first thing you notice is his strong Russian accent. The second is how little he seems to care whether or not you’re impressed by it. He speaks modestly, carefully, and without pretense. He’s not trying to sell you something. He’s just telling you what he knows. And what he knows happens to span decades of hands-on telescope making, optical design, and a kind of earned wisdom you don’t find in books.

Yuri was born in June of 1956 in the Ural region of the Soviet Union. His fascination with the stars began early, long before college or career. In August of 1963, as a young boy, he tried to catch a shooting star with a small can, probably knowing it wouldn’t work, but wanting to try anyway. By the time he was ten, he had built his first telescope: a 30mm Kepler-style scope with an inverted image, assembled more out of curiosity than calculation. In 1969, three years after building that first telescope, he discovered a Russian translation of Ray’s The Stars: A New Way to See Them. “I was lucky to find it,” he says. “This book put constellations in the right order for me.” He was mapping the sky not with equipment, but with wonder.

History of Yuri Petrunin: The man behind TEC Telescopes

Throughout the 1970s and 1980s, Yuri didn’t just observe-he built. He experimented with small refractors, made his own mirrors, mounted stepper drives, and even designed a 160mm f/2 Schmidt camera. While serving in the Soviet army in 1975, he claims to have spotted what he thought was a nova in Cygnus-what we now know as V1500 Cygni, a real and recorded event. Whether it was truly his to discover or not, he noticed it not from an observatory, but during an evening march with his platoon. That de tail tells you everything about the kind of observer he is.

Yuri attended amateur telescope-making seminars and solar eclipse expeditions across Kazakhstan, Moscow, Baku, and Kiev through the 1980s. He developed photometers for comets, fiber optic comparators, and specialized mounts. He wasn't part of a formal lab. He was working in garages, in shared spaces, and with limited resources-fueled by interest more than funding.

In 1990, during a tourist trip to Czechoslovakia, he made a life-altering decision. He quietly slipped away from the group and did not return. He escaped in November and came to the United States in the spring of 1991. By November, he had arrived in the United States as a political refugee. He showed up with his knowledge, his hands, and his quiet determination. Within two years, he was attending the Riverside Telescope Makers Conference in California and starting to rebuild his path in a new land.

Yuri’s first job in the States was with JMI, a private telescope company. It gave him a foothold, but not a future. After two years, he struck out on his own. He had no choice, really-he wasn’t someone built to assemble other people’s ideas. He wanted to build things right.

And so began Telescope Engineering Company-TEC. It’s a family-run business where Yuri, his wife, and their children all play a part. He still tests every telescope himself before it leaves the shop. His hands are still on the optics, and his mind is still on the mount. TEC builds apochromatic refractors ranging from 110mm up to 300mm, offering multiple versions for each size, triplets for wide-field use, slower doublets for those chasing contrast and clarity.

When asked what makes a telescope great, Yuri answers like someone who’s thought about it longer than most people have been alive. He’ll tell you it’s not just about glass. You need the mechanics to match, the balance to hold, and the atmosphere to cooperate. A perfect lens won’t perform if the structure around it sags or flexes. That’s something you learn by doing-not theorizing. TEC’s designs are built for the real world. That means stable mechanical supports, smart thermal behavior, and optical systems that perform under stars, not just under test benches.

He’s not one to chase the next big thing. He uses the best modern glass available-fluorite and ultra-low dispersion types-and coats every surface with multi-layer BBAR anti-reflective coatings. But he’ll be the first to remind you that even the finest optics are only as good as the sky, the mount, and the eye behind the eyepiece. A Strehl ratio of 0.99 doesn’t mean much if the seeing is poor or the observer isn’t trained to read subtle contrast. In Yuri’s words, “It’s all one system. Everything multiplies together. Your weakest link always shows.”

Though he doesn’t get much time for personal observing these days, every telescope is tested with an artificial star. He doesn’t hand off that work. That kind of care may not be scalable in a corporate sense, but it’s exactly what gives TEC its staying power.

Ask him about his antique telescope collection and his tone softens a bit. He has several instruments from the early days of astronomy, some no more powerful than 8x, but all original. One may even be the oldest telescope in the United States. He doesn’t collect them to show off. He collects them because they’re reminders-of what can be done with limited tools and unlimited curiosity.

Looking forward, Yuri doesn’t expect the core of visual astronomy to change much. The eye is still the eye. But imaging? That’s moving fast. Sensors, mounts, fast optics-he watches it all closely, not to chase trends, but to meet needs. TEC remains focused on performance in the real world, not just in brochures.

When asked what would’ve changed if Galileo had a TEC APO on his balcony, Yuri says "I would say he would discover much more, details on planets, more satellites around them, the ring of Saturn, galaxies, etc. But that would probably cost him a life. Giordano Bruno (1548–1600) was executed by the Inquisition in 1600, just a few years before Galileo’s discoveries! So I would not offer him a modern telescope at that time."

And that, really, is how Yuri sees things. The equipment matters, but the drive to understand matters more. His telescopes are built not to impress, but to serve. And like the man himself, they’re quiet, careful, and deeply committed to the sky.

We had the rare privilege of speaking with Yuri over the span of a few weeks. He’s a busy man, and more than once, it was clear he’d rather be at his workbench than in an interview. He answers questions thoughtfully, but you get the feeling he’s most at home when his hands are on the optics, not on a keyboard. Still, what follows is a conversation worth preserving-an inside look at one of modern astronomy’s most quietly influential minds.

Below is the conversation.

ScopeTrader: What inspired you to start Telescope Engineering Company (TEC), and how did your journey with optics begin?

Petrunin: My path into optics and ultimately to founding TEC wasn’t exactly straightforward-it emerged more from necessity and passion than from a carefully laid plan. After immigrating to the U.S., I found it difficult to secure a job that matched my prior education and experience. That period of uncertainty led me to accept a position at JMI, a private company in the telescope industry. I worked there for about two years, and while I appreciated the exposure, it became increasingly clear to me that I didn’t want to spend my life working under someone else’s vision. I had ideas of my own-my own standards of precision and craftsmanship-and I realized the only way to pursue them fully was to start my own company.

As for optics-it has always been a quiet fascination of mine, going back to childhood. Unlike most kids who played with action figures or toy cars, I was captivated by lenses. I remember spending hours holding up glass pieces to the light, watching how they bent and magnified the world. It felt like a kind of magic to me, and in a way, it still does. That curiosity matured into a serious interest in optical systems, and eventually, the technical knowledge and hands-on experience I gained allowed me to merge my lifelong fascination with a business that could push optical engineering forward.

ScopeTrader: In your opinion, what makes a telescope "great", is it the optics, the mechanical design, the experience it offers, or something else entirely?

Petrunin: That’s a fascinating question, and I think the answer lies in a combination of both technical and human elements. At its core, a telescope is simply a tool-but what elevates it to something "great" is how it connects with our very human desire to see farther, to understand more, and to reach into the unknown. It’s that drive-to expand our vision beyond Earth-that gives the telescope its true significance.

From a technical standpoint, exceptional optics are obviously essential. But optical quality alone isn’t enough. The truth is, optics cannot function properly without precise, reliable mechanical design. The two are inextricably linked. As you scale up in aperture, the importance of mechanical support becomes even more critical. Large lenses or mirrors are sensitive structures, and if they're not held in perfect alignment-if the support isn’t engineered with exacting care-you lose the very performance that the optics were designed to deliver.

So a "great" telescope isn’t just about one thing. It’s about balance-between optics and mechanics, between function and form, and between the machine itself and the experience it enables. When everything works together harmoniously, it becomes more than just equipment-it becomes a window into the universe.

ScopeTrader: Can you describe the most difficult optical challenge you've faced so far, and how you solved it?

Petrunin: One of the most demanding challenges I’ve faced was aligning the optical system for our 300mm f/1.44 wide-field astrograph-the one pictured. This instrument was pushing the limits not just of optical speed but also mechanical precision. At such a fast focal ratio, even the smallest misalignment results in severe aberrations across the field. It’s a system that demands perfection down to fractions of a millimeter.

The initial alignment process was far more complex than I had anticipated. Standard collimation techniques simply weren’t sufficient. I had to develop and apply a set of specialized adjustment procedures-some of them completely new at the time-to deal with the tight tolerances and optical sensitivity. It wasn’t just about getting the axis right; it was about ensuring stability under real-world conditions, including temperature shifts and physical stress.

The process took nearly two months of intense work-repeated adjustments, test imaging, mechanical tweaks, and patience. Lots of patience. But in the end, the performance was exactly what I had hoped for: pinpoint stars across a very large field, with minimal distortion and stunning resolution. It was one of those moments where deep frustration transformed into quiet satisfaction. Projects like that remind me why I chose this path in the first place.

ScopeTrader: Many amateur astronomers struggle with the trade-off between portability and aperture. How do you balance these considerations in your telescope designs?

Petrunin: That’s one of the most common and important challenges in telescope design-finding the right balance between optical performance and practical usability. Bigger apertures offer more light-gathering power and resolution, but they also come with increased weight, size, and complexity. For many amateur astronomers, especially those who do not have permanent observatory setups, portability becomes a key factor in whether they actually use the telescope regularly.

At TEC, we approach this balance by offering a diverse range of refractor designs-both in aperture and configuration. For example, we offer instruments ranging from 110mm to 250mm, giving users flexibility depending on their needs and observing conditions. But more importantly, we often provide multiple optical configurations for the same aperture. Take our 140mm and 160mm models, for instance: we offer a 140mm f/7 triplet for those seeking compact performance and wide-field imaging, as well as a 140mm f/9.6 doublet for those who prefer a lighter system with simpler glass and potentially better color correction at higher focal ratios. Similarly, our 160mm line includes both an f/7 triplet and an f/11 doublet.

These choices allow customers to match the optical system not just to their technical preferences, but also to their physical and logistical needs. Whether someone wants a grab-and-go setup or a more permanent observatory instrument, we aim to provide solutions that don’t force unnecessary compromises. It’s all about giving the astronomer control-over both the image and the experience.

ScopeTrader: What role does cutting-edge glass technology and coatings play in your current line of telescopes?

Petrunin: In a way, this question answers itself-because high-performance optics demand high-performance materials. At TEC, we exclusively use the highest grades of modern optical glass available. These materials are selected not only for their clarity and consistency, but also for their ability to hold tight tolerances during fabrication and maintain stability over time.

Our triplet and doublet designs incorporate premium glass types such as fluorite and ultra-low dispersion elements, depending on the optical goals of each model. This allows us to minimize chromatic aberration and achieve the kind of contrast and sharpness that serious observers and imagers expect from a top-tier refractor.

When it comes to coatings, we follow the industry standard-but only at its highest level. We use multi-layer BBAR (broadband anti-reflective) coatings on all air-to-glass surfaces, which significantly reduce reflections and increase light transmission. While this might seem like a standard practice-and in some respects, it is-it still plays a critical role in delivering the high-contrast, high-fidelity views that TEC telescopes are known for.

Ultimately, great optical design can’t reach its full potential without equally great materials. That’s why we never cut corners when it comes to glass or coatings. They’re not just components-they're the foundation.

ScopeTrader: What telescope do you personally use most often these days, and why?

Petrunin: To be honest, I don’t have a "favorite" telescope that I regularly use for personal observing-simply because I rarely have the time for casual astronomy anymore. Most of my time under the night sky is spent testing and evaluating our instruments in real-world conditions. That means I rotate through all of our telescopes depending on what’s being built, tuned, or finalized for delivery.

Each new model gets its moment under the stars, where I evaluate optical performance, mechanical behavior, and overall user experience. All production telescopes are tested using an artificial star during final alignment, but this hands-on field testing helps me ensure that every design meets the standards I’ve set for TEC.

I do still enjoy those moments at the eyepiece, even when they’re part of the workday. There’s something deeply satisfying about seeing the final result of precise engineering come to life on a clear night-whether it’s Saturn’s rings or the structure of a distant nebula. But at this stage in my career, my person'al observing time is more about quality assurance than quiet exploration.

ScopeTrader: Tell us about your collection of antique telescopes - what makes them special to you?

Petrunin: I’ve been fortunate to acquire a small but remarkable collection of antique telescopes-some of which date all the way back to the Galilean era. These are not replicas or modern recreations-they are original instruments from the early days of astronomical observation. Some are extremely modest in power, just 8x magnification or so, but that only adds to their charm. These were the tools of pioneers-telescopes that helped shape how we first began to understand our place in the universe.

Among them is a particularly special piece that may well be one of the oldest telescopes in the United States. Its design and materials suggest it was crafted not long after the invention of the telescope itself. Holding it is like holding a moment in history-an artifact from a time when people were first turning lenses skyward and discovering moons, rings, and the roughness of the lunar surface for the very first time.

For me, these instruments aren’t just collectibles-they’re reminders of how far we’ve come. They reflect the passion and curiosity of the early astronomers, many of whom worked with crude optics and limited knowledge, yet managed to unlock profound cosmic truths. There’s something humbling about that. It’s easy to admire modern optics, but it’s important to remember the courage it took to look up with whatever tools were available-and ask the big questions.

ScopeTrader: Do you have a favorite deep-sky object or planetary target you return to again and again?

Petrunin: When I was in fourth grade, I built my first telescope using parts from a broken during WWII German military binocular. It ended up functioning like a Keplerian telescope-beautifully simple, but with everything appearing upside down. I’ll never forget the feeling of looking through it for the first time and seeing people walking and working… all inverted. Even though the image was flipped, it didn’t matter. The excitement of seeing the world magnified through something I had made with my own hands-that moment stayed with me. It was my first real glimpse into the magic of optics.

If I had to choose a favorite (now) deep-sky object, it would probably be the Pleiades-M45. There’s something timeless and delicate about that cluster. The way the stars shimmer in tight formation, wrapped in faint wisps of nebulosity, is always captivating. Even though it’s a relatively simple object compared to distant galaxies or intricate nebulae, I never get tired of revisiting it. It has a calming, almost poetic presence in the night sky.

That said, I also really enjoy what I call “walking” on the Moon-scanning slowly across its surface, observing the fine detail of craters, ridges, and shadow play. The lunar landscape is endlessly fascinating when viewed through high-quality optics. And of course, when the timing is right, I always take a moment to observe Jupiter and Saturn. Seeing the bands of Jupiter or the sharpness of Saturn’s rings-especially with one of our refractors-never fails to impress, even after all these years.

These familiar targets are like old friends. I may not have the luxury of observing as often as I used to, but when I do, I always find myself drawn back to them.

ScopeTrader: What’s one optical design principle I wish more amateur astronomers understood?

Petrunin: I would say that whatever you see through a telescope is a combination (multiplication) of Strehl of atmosphere, Strehl of optics, and Strehl of your eye. Too many people believe the telescope alone is the key-the bigger, the better, the sharper, the more expensive. But that’s only part of the equation. I wish more understood that a telescope does not operate in a vacuum, and optical design isn’t the sole dictator of performance.

You can have a telescope with a Strehl ratio of 0.99-near perfection on paper-but if your local seeing conditions are unstable, or your mount isn’t tracking well, or your eye isn't trained to read subtle contrast, or you have imprefections in your own eye (or age), you’ll never see that perfection. You’re bottlenecked somewhere else.

The performance of any system is limited by its weakest component. Optical design matters, yes-but the atmosphere above your head, the thermal equilibrium of your scope, and even the patience of your observing eye all shape what you actually experience. That's why at TEC, we care deeply about real-world performance-not just lab numbers. We build optics to match reality, not just theory.

So my advice: don’t chase specs in isolation. Understand the system-telescope, sky, and observer. When those come into harmony, that’s when the magic happens.

ScopeTrader: Where do you see Telescope Engineering Company in the next 5-10 years? Are there new technologies or product lines you're especially excited about?

Petrunin: Looking ahead, I believe the core principles of Telescope Engineering Company will remain the same-precision craftsmanship, high-quality optics, and a focus on delivering instruments that serve serious astronomers well. For visual astronomers, I don’t foresee any major technological shifts in the next 5 to 10 years. The fundamentals of observing with the human eye haven't changed much in decades, and I expect that stability to continue. Great refractors are already very close to their physical and optical limits, and we’ve spent years refining our designs to meet that threshold.

On the other hand, the world of imaging is evolving rapidly. New camera technologies, faster optics, advanced mounting systems, and adaptive processing techniques are pushing astrophotography into exciting territory. While our primary focus has been on refractors for both visual and imaging use, we continue to watch the imaging market closely. We’re always exploring where TEC’s strengths in optical precision might intersect with emerging demands in astrophotography.

So while the tools of visual astronomy may not change drastically, the way people use them-especially in hybrid setups or advanced imaging platforms-will continue to grow. TEC will be there to support both sides: offering timeless performance for traditional observers and reliable excellence for those pushing the digital frontier.