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Mewlon-250CRS reflector

Dall-Kirkham Mewlon series reflectors are long focal length telescopes with high F/D focal ratio.

Dall-Kirkham Mewlon series reflectors are long focal length telescopes with high F/D focal ratio. The primary mirror is ellipsoidal while the secondary mirror is spherical. The surface accuracy of the optics is at least λ/20.

The CRS models incorporate a field corrector with ED glass lenses that provides a F/10 focal ratio but above all a higher corrected field than on conventional Mewlon telescope. The motorized focusing, ASCOM compatible, is done by translating the secondary mirror. The fans responsible for heating the primary mirror are managed by 3 temperature sensors located inside and outside the tube.

The Mewlon-250CRS is perfectly suited for planetary observation and imaging, due to its long focal length. It is also ideal for deep sky applications; equipped with the F/7.3 reducer it will allow the imaging of compact objects such as planetary nebulae or galaxies. The integrated 7x50 finder scope is adjustable and serves as a handle for transport.

The optical tube assembly is delivered with a pair of rings connected by a massive plate located under the tube.

Specifications

Optical specifications
Optical design Modified Dall-Kirkham
Combination Concave elliptical primary mirror + convex spherical secondary mirror + field corrector
Diameter 250 mm
At prime focus
Focal length 2500 mm
Focal ratio F/10
Image circle diameter 40 mm
Metal Back Distance 147.9 mm
With focal reducer RD CR0.73X
Focal length 1825 mm
Focal ratio F/7.3
Image Circle Diameter 35 mm
Metal Back Distance 72.2 mm
With Extender EX CR1.5X
Focal length 3780 mm
Focal ratio F/15.1
Image Circle Diameter 44 mm
Metal Back Distance 117.5 mm
Mechanical specifications
Length of the optical tube assembly 945 mm
Diameter of the optical tube assembly 280 mm
Weight 12 kg

Spot diagrams

Mewlon-250CRS at prime focus

Spot-diagram Takahashi Mewlon-250CRS Dall-Kirkham reflector at prime focus

Mewlon-250CRS reflector with RD CR0.73X focal reducer

Spot-diagram Takahashi Mewlon-250CRS Dall-Kirkham reflector with focal reducer RD CR0.73X

Mewlon-250CRS reflector with EX CR1.5X extender

Spot-diagram Takahashi Mewlon-250CRS Dall-Kirkham reflector with EX CR1.5X extender

System-charts

Mewlon-250CRS main system-chart Download  
Mewlon-250CRS with Extender EX CR1.5X Download  

Instruction manual

Mewlon-250CRS instruction manual Download  

Software

ASCOM ActiveFocuser Driver made by Optique Unterlinden Download  
INDI ActiveFocuser Driver made by Optique Unterlinden Download  

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Saturn by Jean-Luc Dauvergne