250mm f/10 corrected telescope with built-in corrector, Active-Focus ASCOM compliant computer focusing, computer controlled cooling system, tube holder. 

This telescope is one of Takahashi’s originals and is a unique reflector designs which combines an elliptical primary mirror and a spherical secondary plus a 3-element corrector.

The M-250CRS can be used at prime focus [with a corrected field], with the dedicated reducer or extender available optionally.

Specifications

Optical system  …………  Corrected Dall-Kirkham
Effective aperture  ……  250mm
Effective focal length    2500mm
Effective focal ratio     10.0
Secondary mirror          72mmø
Resolving power           0.46”
Limiting magnitude        13.8
Light gathering power     1275X
Image circle              40mmø
Backfocus             180.8mm
Metal Back                115.5mm    

With Reducer-CR 0.73X

Effective focal length    1825mm
Effective focal ratio     7.3
Image circle              35mmø
Metal back                 72.8mm  

With Extender-CR 1.5X

Effective focal length    3780mm
Effective focal ratio     15.1
Image circle              44mmø
Metal back                 117.5mm .

Diameter of main tube      280mmø
Total length of main tube  945mm [37.2”]
Total weight of main tube  12kg [26.4 lbs] w/7x50 finder
Finder                     7x50 w/apparent field of 4.2°
                           w/reticle illuminator

Standard Accessories

Hand control, control cable, 50.8mm (2”) extension tube, Allen wrenches (1.5mm, 2mm, 2.5mm & 5mm), inspection certificate & instruction manual.