Takahashi Mewlon 250CRS w/ Built-In Corrector & Active Focus

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Takahashi Mewlon 250CRS w/ Built-In Corrector & Active Focus
Item # TK-TLK2502
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  • The Takahashi Mewlon-250CRS Telescope is a flat field corrected Dall-Kirkham that provides amazing results when used for imaging or visual pursuits.
  • This Mewlon-250 includes an installed 3 element ED corrector.
  • The Takahashi Mewlon-250CRS incorporates Active-Focus, an ASCOM compliant computer focusing feature.
  • The system also includes a three-fan computer controlled cooling system. An included hand controller is used to control focus and cooling.
  • A tube holder and finderscope with bracket are standard in this system.


Takhashi Mewlon-250CRS Corrected Mewlon

When Takahashi developed the correctors for their Mewlon line of telescopes it meant that any Mewlon-250 or 300 ever made could be converted into a flat field corrected telescope. This 3-element ED corrector allowed the Mewlon to be used as an imaging instrument or used as a corrected visual instrument capable of producing flat-field corrected views of the Moon, planets and deep space objects. The 250/300 Mewlons use an electric focus controller that moves the secondary mirror. Takahashi developed the secondary focusing system in 1990 and wanted to improve them with computer control. An ASCOM driver is available for download free from Takahashi Japan website.

The CRS Mewlons are the product of this development. They both employ an ASCOM compliant driven secondary focusing motor that allows the Active Focus system to be controlled by an ASCOM compliant focusing system.

Additionally, to make imaging easier a 3-fan cooling system is included. This system uses three sensors: one on the mirror, a second in the tube and a third outside to monitor and control the low vibration fans to bring the primary to ambient temperature. This can be done manually or controlled by an ASCOM compliant focusing program.

The cooling system is controlled manually or automatically with the hand control. When the sensors read a difference in the temperature of the primary and ambient temperature the fans turn on and cool until the primary is brought to ambient.

The provided hand control is used for manual focusing and cooling and as a connector for the computer controlled focusing program

The USB port is used for the connection to the computer for auto focusing.

The auto focusing system is called Active Focus. Active Focus includes a backlash revision function. The M-250CRS uses a four vane spider to support the pulse motor focusing system. It can be controlled with FocusMax, Maxim DL or similar software.

The M-250CRS is an outstanding medium sized flat field imaging and visual instrument. It weighs 22lbs so it is portable and does not require a large mount to operate, so it can be easily transported to remote sites.

A dedicated f/7.3 reducer and 1.5x extender are available optionally for added flexibility.

A 7x50 illuminated reticle finder and tube holder are standard.

Takahashi Product Number: TLK2502

Additional Information

Additional Information

Manufacturer Takahashi
Telescope Series Takahashi Mewlon
Optical Design Corrected Dall-Kirkham
Mount Type None - Optical Tube Only
Warranty 5 Year Warranty
Telescope Aperture 9.8"
Secondary Aperture 72mm
Telescope Focal Length 2500mm
Telescope Focal Ratio f/10
Back Distance 115.5mm
Image Circle 40mm
Image Across Field Not Provided by Manufacturer
Optical Coatings Not Provided by Manufacturer
Limiting Stellar Magnitude 13.8
Highest Useful Magnification 600x
Optical Tube Outer Diameter 280mm
Length of Optical Tube 37.2"
Optical Tube Weight 26.4 lbs.
Tube Color or Finish Gloss White
Finder Included 7 x 50 Optical Finder
Eyepiece(s) Included None
Diagonal Included? No - Not Required
Dew Shield Included? No, Sold Separately
Dew Shield Outside Diameter N/A
OTA Mount Type N/A
Power Adapter Included None - Does Not Require Power
Objects in Database N/A
Hand Controller Included? Yes
Alignment Procedure N/A
Counterweights Included N/A
Mount Weight N/A
Total Telescope Weight 26.4 lbs.
Tripod Type Included None, Sold Separately
Included Items

Included Items

  • Takhashi Mewlon-250CRS Corrected Mewlon
  • Active Focus
  • Computer Controlled Cooling Unit
  • Tube Holder
  • 7x50 Illuminated Reticle Finderscope
  • Bracket
  • Hand Controller
Questions & Answers

Product Questions

What additional items would I require, not already included with this telescope, to secure it to a Losmandy G11 GEM?
I have a Sky-Watcher AZ-EQ6 GT Mount. What would I need to attach the Mewlon 250CRS to that mount?

I have a Celestron Advanced VX Mount. What would I need to attach the Mewlon 250CRS to that mount?
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