Astro-Physics 10 Inch (25.4cm) f14.6 Maksutov-Cassegrain High Resolution Telescope

Astro-Physics Co. who are known for making the world's most advanced, versatile, and desired lines of Apochromatic refractor telescopes began the year 2000 with the announcement of their first production Catadioptric telescope!

After more than a decade of research and development to "get it right" Astro-Physics has sold out the first of a limited number of Maksutov"Mak" telescopes. Designated the Astro-Physics 10 inch f14.6 Maksutov Apochromat telescope, this is a compact 33 lb. (15 kg) high resolution instrument designed to provide refractor like views (and images) of the brighter, small objects including the planets, moon, double stars, and the like.Astro-Physics has been working to make a telescope that would be more compact, perform well in temperature extremes around the world, and meet their exacting requirements for optical and mechanical excellence: they have continued their tradition of innovative excellence.

A further goal in this development effort was to equal or to approach the performance of their highly prized triplet apochromatic refractors in at least certain applications. One thought in producing these Catadioptric telescopes is that if a number of customers who do not require the versatility of the Apo refractors (which perform superbly well at extremely high magnifications, and down to very low magnifications) will order the Mak telescopes instead of the triplet Apos then this may take some of the burden from the Triplet production line, and thereby helpAstro-Physics to satisfy a far greater number of the more demanding amateur and professional clientele.

Deliveries from the first production run will commence in limited numbers in April of year 2000. It is likely that production will accelerate, and the 10 inch model is likely to be followed by other variants of the design in terms of designed function and aperture.

The primary mirror is a truncated cone designed to eliminate as much thermal mass as possible. The rear surface of the mirror is fine ground and then polished, a process which also helps internal trapped heat to radiate out the open back. By grinding the edge and back of this mirror, any tiny stresses are relieved which could otherwise introduce unwanted distortions in the highly accurate front surface at varying ambient temperatures. In side-by-side tests against closed back scopes with conventional molded mirrors, theAstro-Physics design was faster, by far, in achieving a stable and accurate image.

Any optical imperfections such as a degree of surface roughness and zonal errors on the optical surface will compound the problem.Astro-Physics tested a commercial telescope where the central obstruction, optical errors and surface roughness were large enough to cause the first diffraction ring and central Airy disc to have almost equal brightness (with a 35% obstruction, theoretically there should be at least a4 to 1 difference). Even so, this sample telescope "tested" very well on the star test - it had quite similar inside and outside Fresnel patterns and might be judged to be textbook perfect by the star test. Yet it was a very poor performer on all but the most steady of nights, when the seeing was essentially perfect. The slightest motion in the atmosphere would result in a display of "cotton ball" stars. This is one reason whyAstro-Physics and Company Seven have not been a major fans of the "star test" to evaluate the actual performance of a telescope. The only unbiased way to measure an optic is withinterferometry, or by an MTF (modulation transfer function) test, or with a PSF (point spread function) test, which measures the relative strength of the Airy disc versus the diffraction rings with the image in focus.

Astro-Physics has endeavored to achieve the highest absorption of stray light possible by employing state of the art baffling and anti-reflection techniques; this will help to provide the user with maximum contrast. The exterior of the telescope is finished in a durable textured off white finish, with black anodized focuser and cells; these will retain their beauty for many years. You will appreciate the unique design and fine craftsmanship of this telescope.

Knife edge baffles are machined into the walls of the telescope optical tube and of the focuser draw tube, these and painted flat black in order to maximize contrast by essentially eliminating any internal reflections. The inside diameter (I.D.) of the draw tube permits the avid astrophotographer to employ up to a 35mm format film or CCD camera to capture images. You can use standard 2 inch diameter accessories, and with the furnished 1.25 inch adapter (threaded for 48mm filters) use common oculars and accessories too. Recessed brass locking rings are installed at each thumbscrew location; as you tighten a thumbscrew a brass locking ring clamps onto the part that has been inserted; consequently the focuser draw tube and any accessories are held securely in place and will not mar the surface of your accessories. This is particularly important considering the heavy and expensive accessories that you may use.

* Specifications are subject to change without notice.

Your local seeing conditions will greatly affect whether or not you may operate the telescope at its highest magnifications. Please call to discuss this if you have any questions.

Right: Company Seven ATA Case custom fitted for a Astro-Physics 13cm EDT Apochromat Telescope with 2.7 inch Focuser (65,974 bytes).Click on image to see enlarged view (215,942 bytes).

Features include:

Left: Astro-Physics Model 900 Mount in optional Company Seven ATA case.Case 1 of 2 shown here, with Declination housing (left side shown) with GTO Keypad Controllerand Counterweight Shaft (94,326 bytes).

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