Optical design and facilities
Our TI 35 (both models), TI 45 f/4 and f/5,2, TI 55 f/3,5 and f/4,9 and TI 65 f/3,5 and f/4,7 Astrograph are derived from the configuration Harmer-Wynne (designed for the first time and published in 1976 – Royal Astronomical Society, Monthly Notices, vol. 177, Oct. 1976, p. 25P-30P). The Harmer-Wynne instruments have the particularity of combining a parabolic primary mirror with a spherical secondary mirror and obtain a corrected wide field with the aid of a two elements corrector.
The first TI 45 DFL under test
In our Astrographs, it is introduced a further refractive element correction (in ED glass) – this 3th lens introduction was done by Leonardo Priami in late 2010 as described in its web site LINK-, reaching extremely wide true diffraction limited corrected field (over 80 mm in diameter for the TI45 f/4) without introduce color aberrations (from 400 nm to 1,6 micron of wavelength). These performances of very fast and very corrected optics allows to this optics to be used with success both in narrow band filter imaging and in Near Infrared imaging. This optical configuration -called here Modified Harmer Wynne– is used now for ALL our Astrographs.
Our faster astrographs, TI55 f/2,6 and TI65 f/2,6 represent a further primacy on the market being the astrographs with greater diameter and higher luminosity on the market of semi-professional instruments. And thanks to the lightened mirrors they can be supported by commercial mounts. They use a custom designed 6″ Wynne corrector (TI-160 Wynne corrector).
Only the “slower” astrographs, TI45 f/8, (now available only on request) we use a Corrected Cassegrain system with two element corrector that deliver awesome performances.
All the optical configurations had been conceived and optimized using the state of the art software.
Every small details was inspected, analyzed and optimized to reach the best performances as in terms of avoiding stray light. Fully articulated non-sequential analysis has been performed for each systems to optimize sizes, position and shape of better baffling systems.
Only uncompromising performance is the driver for our optical requirements.
The state of the art equipment is used for manufacture, test, analyze, align our optical systems as professional optical bench and Zygo interferometers.
For the assembly, test and collimation phase, Telescopi Italiani uses a 100×100 array Shack-Hartmann wave front analyzer in double pass test for best and most sensitive verification.
Zygo Interferometer used for test correctors lenses
A DEA allow us to check and verify all geometrical dimensions and tolerances.
A convex spherical mirror under geometrical dimensional check
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