Telescopi Italiani TI35 f/3.5 Modified Harmer Wynne Astrograph

Telescopi Italiani TI35 f/3.5 — 350mm Super-Fast Astrograph for Advanced Astrophotography

The Telescopi Italiani TI35 f/3.5 is a 350mm (14-inch) Modified Harmer Wynne astrograph engineered for demanding astrophotographers and remote observatory installations. Available exclusively in the United States from Deep Space Products — Telescopi Italiani's first dealer worldwide — the TI35 f/3.5 delivers a true diffraction-limited field exceeding 62mm in diameter at a super-fast 1,230mm focal length. At just 23 kg (51 lbs) and 720mm (28.4 inches) long, it is among the lightest and most compact 350mm (14-inch) astrographs available anywhere, collecting data fast enough to transform a night of narrowband imaging from a handful of usable subs into a deep, signal-rich dataset.

The challenge with large-aperture fast astrographs has always been the tradeoff between optical performance, structural rigidity, and weight. Heavier instruments demand heavier mounts, larger piers, and more rigid observatory structures — all of which drive up cost and complexity. Telescopi Italiani, founded by aerospace engineer Leonardo Priami and instrument designer Claudio Dandolo, attacked this problem with aerospace-grade materials and FEM-optimized structural design. The result is a 350mm (14-inch) astrograph that can ride on a 70 lbs (30 kg) class equatorial mount (e.g., 10Micron GM2000HPS II or AZ2000HPS), fits through a standard doorway, and still delivers spot diagrams that rival instruments costing significantly more.

Modified Harmer Wynne optical design

The TI35 f/3.5 uses an aspheric primary mirror, a spherical secondary mirror, and a 116mm three-element ED glass corrector to achieve its wide, flat, diffraction-limited field. The spherical secondary is a deliberate engineering choice — it dramatically simplifies collimation compared to designs requiring two aspheric surfaces, which matters both during initial setup and for long-term mechanical stability in remote installations where nobody is standing at the telescope at 2 a.m. The corrector's ED glass elements eliminate chromatic aberration across a wide spectral range from 400nm to 1,200nm, making the TI35 equally effective for broadband RGB, narrowband (Ha, OIII, SII), and near-infrared imaging.

At f/3.5 with a 1,230mm focal length, the TI35 achieves a 62mm diffraction-limited field with spot diagram RMS diameters of just 2.29 microns at 26mm off-axis and 3.90 microns at 30mm off-axis (polychromatic, 400–700nm). Vignetting stays below 6% at the 26mm mark and 9% at 30mm — impressively tight for an f/3.5 system of this aperture. That corrected field comfortably covers full-frame 36 × 24mm sensors with room to spare. And at f/3.5, the TI35 collects data roughly twice as fast per sub-frame as an f/5 system of the same aperture — a significant advantage for narrowband imaging of faint emission nebulae, where every photon counts.

Telescopi Italiani publishes detailed spot diagrams, encircled energy curves, and relative illumination data for every model — more performance documentation than most competing manufacturers provide. Deep Space Products can walk you through these diagrams and help you understand what they mean for your specific sensor and filter combination.

Carbon fiber construction and thermal stability

Every structural element of the TI35 is designed using finite element analysis and built with purpose. The truss poles are full carbon fiber, and the structural body uses carbon fiber sandwich construction — the same approach used in aerospace and motorsport applications where stiffness-to-weight ratio is critical. This isn't cosmetic carbon fiber wrap over an aluminum frame. The carbon fiber is structural, and it delivers two important benefits: the 51 lbs (23 kg) total weight, and a coefficient of thermal expansion low enough that focus shift during a night's temperature swing is minimal.

The TI35's light advantage is significant for mount selection — it opens up the possibility of using a mount in the 70 lbs (30 kg) payload class rather than requiring a 100+ lbs (45+ kg) class instrument, which translates directly to real savings in mount cost and pier requirements for a permanent installation.

Integrated electronics for remote operation

The TI35 comes standard with an integrated electronic control system providing WiFi and Ethernet connectivity for full remote control of telescope functions. The built-in secondary mirror electronic focuser is ASCOM Alpaca compatible, allowing direct integration with popular observatory control software including TheSky, Sequence Generator Pro, N.I.N.A., and Voyager. No third-party focuser is needed — the focusing mechanism is part of the instrument, optimized for the specific mechanical requirements of this optical design.

Optional accessories include the TI110 Field Rotator (ASCOM Alpaca compatible) for alt-az mount installations or precise framing control, an automated dust cover (also ASCOM Alpaca compatible) for unattended remote operation, and the TI-112 Dovetail System for fast, repeatable OTA balancing. The full automation package makes the TI35 well suited for remote observatory installations like those at DSP Remote, where unattended operation over weeks and months is the standard workflow.

Quartz mirror option

For installations where thermal performance is paramount, Telescopi Italiani offers an optional upgrade to fused silica (quartz) primary and secondary mirrors. Quartz has a near-zero coefficient of thermal expansion — roughly 15 times lower than standard glass — which virtually eliminates figure distortion during temperature changes. Combined with the carbon fiber structure, the quartz mirror option makes the TI35 one of the most thermally stable astrographs in its aperture class. This is a meaningful upgrade for remote observatories in environments with large diurnal temperature swings, and Deep Space Products can advise on whether it's the right choice for your site.

Where the TI35 f/3.5 fits in the astrograph landscape

The 14-inch fast astrograph category has a few well-known options. The Officina Stellare RiFast 300 (12-inch, f/3.8, 1,140mm focal length) is a similar Modified Harmer Wynne design from another Italian manufacturer, with a 60mm corrected field and comparable weight — but it gives up 2 inches of aperture and is slightly slower. The Takahashi CCA-250 (10-inch, f/5.0 native, f/3.6 with reducer) is a respected instrument with an 88mm corrected field, but at 250mm aperture it collects significantly less light. The PlaneWave CDK14 (14-inch, f/7.2) matches the TI35 on aperture and offers a 70mm corrected field, but at its native focal ratio it requires much longer exposures — and adding a focal reducer introduces its own optical compromises and imaging train complexity.

The TI35 f/3.5's niche is clear: no other production astrograph delivers 350mm of aperture at f/3.5 in a sub-25 kg (51 lbs) package with a 62mm+ diffraction-limited corrected field. If your imaging goals demand large aperture, fast focal ratio, wide corrected coverage for full-frame sensors, and the ability to mount it all on a mid-range equatorial mount — the TI35 occupies a space that is genuinely unique.

Talk to Deep Space Products about the TI35

As Telescopi Italiani's exclusive U.S. dealer, Deep Space Products is your direct source for the TI35 in North America. Choosing a flagship astrograph is a system-level decision — the telescope, mount, camera, and automation software all need to work together. DSP brings observatory integration expertise to help you configure the right system, whether that's a portable dark-site rig or a permanent remote installation. Contact our team to discuss the TI35 f/3.5, request current pricing, or start planning your imaging system.