TELE VUE TV85 APO TELESCOPE - IVORY PACKAGE
he Tele Vue-85 is a doublet APO that is perfect for anyone anywhere. It is small enough to be taken as a carry-on for most airlines, It’s 85mm aperture will allow you resolve double stars, lunar detail and wispy nebulas. It is also capable of taking great astro-images
The objective lens of the 85 is of an SD air spaced doublet design where two lenses (crown and flint) are matched to work as one; the positive element is of a fluorocrown substitute with special dispersion glass. This design allows very good color correction - appearing excellent to most people. While spherical correction is very good also, with the air gap contributing to this correction. Images of the stars and the planets are presented in their natural colors, daytime objects viewed at commonly used magnifications will appear quite three dimensional and sharp and high contrast without annoying purple fringes (secondary color) common to less sophisticated refractors.
The objective's four air to glass surfaces have a multilayer antireflection coatings that improves overall light transmission to greater than 94% in the visual wavelengths. So, the system has about 140 times the light gathering power of the unaided human eye making it through the objective lens. On most nights, the settling down time for the lens is on the order of minutes, and even in subfreezing conditions it rarely requires more than 30 minutes to acclimate from typical room temperature.
The lens is so well figured that it is capable of operating at 200X or more cleanly with optional eyepieces; this reaches that threshold necessary to routinely obtain meaningful views of the planets showing several bands and their shades of color (beige, tan, browns) on Jupiter, the Cassini division on Saturn, the polar cap on a fiery red Mars. With an eyepiece that shows 1/2 degree field or so, take a walk on our apparently three dimensional Moon! or follow its terminator throughout the moons phases (optional neutral density filter suggested to tone down its brightness). It can resolve objects on the moon as small as 5.3 km in diameter; it will see the four largest moons of Jupiter and their shadows cast on the surface when they transit past the planet!
All 85 models delivered since February 1999 include a refined TeleVue 2 inch diameter "Everbrite" diagonal (or "zenith") mirror. The "Everbrite" mirror features a very high-tech dielectric coating (developed originally for military optics used in hostile environments such as blowing desert sand) which provide optimum performance and years of use. This new TeleVue 2 inch diagonal has no aluminum or other reflective metal coating. Instead, the reflective surface consists of 52 layers of thin film oxides similar to those used in antireflection coatings.
The coatings are deposited by an electron beam evaporator at a high temperature. The result is that reflectivity is above 99% over the entire 4000 to 7000 Angstrom photo-visual range. Thin film coatings have extremely low surface scatter compared to aluminum or enhanced aluminum coatings; examination with a laser source shows approximately a 5 fold improvement in surface scatter.
The mirror diagonal provides a comfortable viewing position for the observer by diverting the image at the rear of the telescope off axis by 90 degrees to the side, with minimal degradation of image quality. The view when using the telescope as it is provided will appear to be right side up, and is reversed left to right; this is not usually a problem for astronomy or nature observing because the image quality provided by the high quality mirror and 2 inch diameters panoramic oculars is exceptional.