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ASA AZ1750 Ritchey-Chrétien 1750mm F6 Telescope System

Price includes VAT, plus delivery



The ASA AZ1750 is an azimuthally mounted telescope with Nasmyth focus, in which all experience of the designer, Dr Philipp Keller are incorporated and combined with state-of-the-art CNC technology from ASA.

The azimuthal design allows a very compact dimension for this telescope opening. The Nasmyth type focus is steered by a motor-rotated Tertiary mirror either through the left or right fork side and you can switch between these foci within a few seconds with a mouse click. For example, you can visually use one of the foci, the other photographically, without constantly having to rebuild. Likewise, it is of course conceivable to equip one side with a planetary camera, the other hand, with a reducer. Since all devices are mounted in Nasmyth focus at the center of gravity, this eliminates the need to balance with different cameras and accessories. For visual observation, this provides maximum comfort because the viewing height is always at the same height and the view is always horizontal.

The ASA AZ1750 achieves unprecedented positioning and tracking accuracy thanks to ASA's Direct Drive technology, combined together with an encoder resolution on the telescope axis of better than 1/100 arc seconds. This is also a benefit of the azimuthal construction, which avoids the hysteresis effects caused by parallactically mounted telescopes and load changes. The optional ASA Derotator precisely corrects the field rotation that occurs with all azimuthally mounted telescopes during long exposures. Also with this focal length, seeing-limited shots are no problem even without autoguiding at shutter speeds of 5 minutes thanks to ASA's MLPT tracking system.

The optics of the AZ1750 are uncompromised. It features quartz glass optics made in house by ASA (L / 8 Wavefront Peak to Valley), making ASA one of the few manufacturers who can achieve the surface quality required for outstanding imaging performance in large diameter RC and Nasmyth systems.

The AZ1750's optical design uses the RC system (including optional correctors). Due to two aspherical optics, these systems are more complicated to produce than, for example, a Dall Kirkham system, which leaves one of the two mirrors spherical, resulting in large aberrations. For us, this optical compromise is out of the question. As an example of the quality acheived by ASA, see the Jupiter animation below made by ASA customers using an AZ1750 telescope system. Normally large RC telescopes with large central obstructions do not make good planetary imaging telescopes due to low contrast. It can be seen here that this is not true of the AZ1750!

The AZ1750 is built to order and subject to us carrying out a detailed site survey to assess suitability for mounting and installing the telescope. Obviously this is a large and specialist telescope that requires installation and as such is subject to the associated extra costs.

Optical design RC Ritchey-Chrétien
Focal ratio f6 Nasmyth Focus
Focuser Secondary Mirror
Central obstruction 42%
Back focus 360mm
Image Circle 150mm
Primary Mirror ≥1750mm f2
Tracking precision with ASA mount <0,25” RMS within 5 minutes tracking time (for altitude 20° to 85°; without seeing effects and with a pointing model in use) over 5 min 0,05” RMS/min
Pointing precision with ASA mount <8” RMS with pointing model (for altitude 20° to 85°)
Optional Equipment -
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