Pollux

Project - description

We are making this telescope for the IAS (Internationale Amateur-Sternwarte). It will be installed in Namibia at Hakos, later we want to install it on the Gamsberg-plateau.
The mechanics are nearly finished now, we are currently working on the field rotators and focusing systems. The mounting is a computercontrolled, azimutal mounting with field derotator. We can use the telescope in dual-focus mode. The Newtonfocus can be used with f/4 (without corrector) and f/4.5 (with corrector) and the Nasmythfocus can be used with f/14.6 (without corrector) and f/15.4 (with corrector).

Technical data
Free aperture                                                  805mm
Focal length Newton-focus                             3201mm
Focal length Newton-focus (with corrector)    3557mm
Focal length Nasmyth-focus                           11795mm
Focal length Nasmyth-focus (with corrector) 12387mm

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design study of the Pollux telescope 3D-CAD

Optics

Below you can see the fantastic optical quality of the Pollux optic. It delivers a much better than diffraction limited performance in the Newton focus and in the Nasmyth focus.

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Newton-focus

Pol_Int_Cass.JPG (8330 Byte)
Nasmyth-focus

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Newton-Diagonal

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Nasmyth-Diagonal

The Newton focus can be used with a 3-lens Wynne-corrector that is able to achieve spotdiagrams of less than 0.011mm on a field diameter of 1.6 degree.
The Nasmyth focus can be used with a 2-lens corrector that is diffraction limited on a field diameter of 100mm (27 arc minutes). The telescope can be changed from the Newton focus to the Nasmyth focus in less than 3 minutes.

Spotdiagram Newton focus

Spotdiagram Nasmyth focus

Specials

Encoder
We use Encoders from Heidenhain, that are among the most accurate encoders in the world. The resolution is about 0.2 arc seconds on the axis of the telescope. This enables accurate tracking for CCD-applications for a time frame of about 10 minutes. Furthermore we have a very accurate pointing accuracy. All gearing errors are corrected realtime.

Nasmyth-Fokus
One of the important features is the Nasmyth-focus. This focus has the advantage that it is easily accessible and always in the same height and a lot of weight can be installed there. We will keep you informed about the progress of the telescope here.