TI45: A new generation Harmer Wynne Astrograph
The TI 45 is a new generation astrograph born after in-depth and extensive studies lasted five years.
It has 450 mm of optical aperture and it combines a number of innovative features and special solutions.
The TI 45 Astrograph range include four models:
- TI 45 – f/4.0 Focal length: 1800 mm
- TI 45 – f/8.0 Focal length: 3600 mm
- TI 45 Dual Focal Length (DFL) f/4.0 – f/8.0
- TI 45 – f/5.2 Focal length: 2350 mm
The fast f/4 and the f/5.2 models are based on a Modified Harmer-Wynne optical configuration with three elements corrector.
The “all-around” f/8 configuration, is based Corrected Cassegrain with two elements corrector.
Fused Silica (Quartz) primary mirror is available as option (see Price List). 
Fused Silica (Quartz) performs an awesome thermal expansion coefficient of 5.4 x 10-7/℃ , 6 time less than borosilicate glasses.
Lightweight Quartz primary mirror is available as option (see Price List). Near-to-zero CTE material + lightweight shape = best solution.
The design was carried out by a professional team driven by an aerospace engineer.
Mechanical design was performed in a 3D environment and FEM analysis have driven the sizing of the components.
In the TI45 DFL model the rear flange include an integrated electronical focuser and 110 mm field rotator designed and manufactured with the best performances ever seen. The other TI45 models still have the TI110 Field Rotator inside the rear flange and perform an extremely precise secondary mirror focusing system.
From optical, mechanical, electronic and design point of view, the TI45 Astrograph is the most advanced telescope which you can find on the world market.
The TI 45 DFL Astrograph: Not a simple telescope, but it is really two telescopes in one.
In the DFL model, the TWO configurations (the fast f/4 and the “all-around” f/8) are “native” and both optimized. No “Barlow” lenses are used, neither “focal reducer” to modify focal length. The two configuration share only the primary mirror and the structure. You can shift from one to the other in less than five minutes without loss of collimation thanks to the special secondaries holder and thanks to the spherical secondary mirror of the f/4 setup. You can leave in place all your instruments (CCD camera, filter wheel, focuser, AO, OAG, ecc), after a configuration change, you only have to refocus a little!
TI45 – DFL
Aperture: 450 mm
Dual focal Length f/4 – f/8
The versatile Astrograph
TI45 – 4.0
Aperture: 450 mm
Focal Length 1800 mm – f/4
The fast Astrograph
TI45 – 5.2
Aperture: 450 mm
Focal Length 2350 mm – f/5.2
All-around Astrograph
TI45 – 8.0
Aperture: 450 mm
Focal Length 3600 mm – f/8.0
The deep-sky Astrograph
THE TI45 MOST IMPORTANT FEATURES:
- Effective optical aperture: 450 mm
- For the DFL model: Native dual focal length (1800 mm f/4, 3600 mm f/8) interchangeable within five minutes
- Awesome optical performances for each configurations
- Extreme stiffnes and thermal stability (thanks to extensive use of carbon fiber)
- Extreme lightness (thanks to extensive use of carbon fiber)
- Easy collimation
- Compact dimensions
- Built in 4″ electronic field rotator (ASCOM Alpaca compatible)
- Automated dust cover (ASCOM Alpaca compatible)
- Integrated electronic focuser (ASCOM Alpaca compatible)
- Built in electronic control boards
- WI-FI Telescope Control Software
- Extreme modern Italian design
| TI 45 Astrograph - | |||
| Technical data | f/4 | f/8 | f/5,2 |
| Overall dimensions (mm) | 560x560x1020 | 560x560x1120 | 560x560x1140 |
| Weight (kg) - Standard mirrors | 43 | 42 (45 DFL model) | 42 |
| Focal length (mm) | 1800 | 3600 | 2350 |
| Optical Configuration | Modified Harmer-Wynne | Corrected Cassegrain | Modified Harmer-Wynne |
| Parabolic Primary Mirror | |||
| Diameter (mm) | 462 | ||
| Thickness (mm) | 50 | ||
| Effective optical aperture (mm) | 450 | ||
| Material | Borosilicate glass | ||
| Coating | Alum. Enanced >94% | ||
| Secondary Mirror | |||
| Diameter (mm) | 238 | 166 | 220 |
| Thickness (mm) | 24 | 20 | 22 |
| Shape | Spheric | Hyperbolic | Spheric |
| Material | Borosilicate glass | ||
| Coating | Alum. Enanced >94% | ||
| Corrector | |||
| Type | 3-Lenses ED | 2-Lenses | 3-Lenses ED |
| Corrector lens diameter (mm) | 126 | 94 | 136 |
| Coating | Multy layers 400-900 nm | ||
| Real Diffraction Limited field diameter (mm) (considering Polychromatic 400/700 nm) | 83 | 72 | 90 |
| Effective Obstruction (of the secondary baffle) (%) | 54,6% | 38,7% | 50,7% |
| Light incoming (% of aperture area) | 70,0% | 83,8% | 74,1% |
| Back Focus from rear flange (mm) | 188 | 188 | 200 |
| Loss of light (vignetting) @ 26 mm from axis (%) | 5,0% | 5,0% | 3,5% |
| Loss of light (vignetting) @ 30 mm from axis (%) | 11,0% | 7,0% | 7,5% |
| Spot Diagram RMS Diameter @ 26 mm from axis - Poly 400-700 nm (micron) | 2,2 | 4,52 | 2,22 |
| Spot Diagram RMS Diameter @ 30 mm from axis - Poly 400-700 nm (micron) | 2,58 | 6,64 | 2,57 |
