Takahashi FSQ-85EDX Petzval Quadruplet Astrograph package

Takahashi FSQ-85EDX Petzval Quadruplet Astrograph package with cradle, finder bracket and 6x30 optical finder. An exceptional instrument for wide-field deep-sky imaging, thanks to the fast focal ratio (F/5.3) and a wide, corrected flat-field ready for sensor up to 35 mm format.

This updated version comes with 2" and 1.25" adapters, M72 52 mm long extension tube TKA23250, TKA37582 1,01x field flattener for large format sensors. Cradle, 6x30 optical finder a finder bracket are included as well in this package version.

With the success of short refractors and improvement of the performances of CCD and DSLR cameras, Takahashi introduces the FSQ-85ED, more itinerant than the FSQ-106ED model, and intended for deep-sky and wide field photographers.

The FSQ-85ED is based on the same ED glass Petzval quadruplet design as the FSQ-106ED model, but offering a focal length of 450mm and a photo field of 5.6°, which is ideal for photography. It is equipped with an oversized rack-and-pinion focuser and an independent camera angle adapter. An optional focal reducer is also available in order to transform the refractor into a true astronomical teleobjective with a focal length of 328mm and with a focal ratio of 3.9, providing a field of view of 7° and a 40mm image circle.

Weighting only 4kg without accessories, you will not need a heavy mount. It becomes easy to take pictures of the deep-sky while transporting your telescope under the best skies.

Features

The FSQ-85ED modified Petzval quadruplet design is the same as the FSQ-106ED one. It has a built-in flattener inside the optical tube, offering a field of 5.6°, essential for taking quality pictures. It is thus not necessary to add any other optional accessory. With a focal length of 450mm, the image circle is 44mm width. The addition of a 0.73x focal reducer makes it possible to change the focal ratio from 450mm (F/5.3) into 328mm (F/3.9). It then becomes a true teleobjective for the deep sky.

The FSQ-85ED is equipped with an oversized rack-and-pinion focuser, just like the 106ED. However, the camera angle adjuster has been taking apart from the focuser to come back to a more traditional position where accessories are screwed on focuser tube.

The rack-and-pinion has been oversized on purpose to gain in precision and effectiveness. This focuser is a model of precision. It is driven by two focus wheels with a 1/7 microfocuser.

Although its design resolutely directs it towards astrophotography, the FSQ-85ED can be equipped with various accessories including those for observation. Please go to the system-charts section to see the different possible options. With a 220mm back focus, no matter which accessory you will pick up, you will have different choices of uses and assemblies.

The FSQ-85ED has a specific focal reducer that deep-sky astrophotographers, wishing to have a very large field, will enjoy.

As on the FSQ-106ED, the built-in field flattener, perfectly designed and manufactured, gives an almost homogeneous flat field of 44mm diameter. At prime focus, at the edge of field (22mm from the optical axis), stars remain pinpoints, including on pixels of 7µ width. The addition of the Reducer-QE 0.73x, specifically designed for this quadruplet, makes it possible to gain in field of view on the widest deep-sky objects while preserving the initial optical performances.

Optical specifications

• Design: Modified Petzval quadruplet apochromat
• Aperture: 85 mm
• Focal ratio: F/5.3
• Focal length: 450 mm
• Corrected field: 44 mm
• 3" focuser with 7:1 microfocuser and Camera Angle Adjuster (CAA)
• Spot size in axis: 4 micron RMS
• Spot size 22 mm from axis: 7 micron RMS
• Field of view: 5.6°
• Back focus: 197.5 mm
• Resolving power: 1.5"
• Included with package version: cradle, finder bracket and 6x30 optical finder

Used in combination with Reducer-QE 0.73x

• Focal ratio: F/3.86
• Focal length: 328 mm
• Corrected field: 40mm
• Field of view: 7°
• Metal back distance: 72.2 mm