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.
Takhashi Mewlon-250CRS Corrected Mewlon
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
SKU TK-TLK2502 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
- Takhashi Mewlon-250CRS Corrected Mewlon
- Active Focus
- Computer Controlled Cooling Unit
- Tube Holder
- 7x50 Illuminated Reticle Finderscope
- Hand Controller
- Questions & Answers
Product QuestionsWhat additional items would I require, not already included with this telescope, to secure it to a Losmandy G11 GEM?Question by: Bil the Galactic Hero on Jan 15, 2015 5:48:54 AMYou will need to get an Extra Large BT Tech Takahashi dovetail (http://www.optcorp.com/bt-tech-dovetail-plate-for-takahashi-frc300-brc300-m250s-m300-black.html) to fit the 125mm spacing on the bottom of the M250 rings. This plate is wide enough that you may need to replace the knob on the G11 saddle with a hex head set screw to clear properly.Answer by: Chris (Admin) on Jan 16, 2015 9:04:03 AM
I have a Celestron Advanced VX Mount. What would I need to attach the Mewlon 250CRS to that mount?Question by: hamad on Mar 28, 2016 7:41:00 AMWhile the base OTA weight is 26.4 lbs on the Mewlon 250CRS, once you add the rings, mounting plate, diagonal and eyepiece, you will be closer to 35+ lbs, which is too heavy for the AVX mount. I would suggest considering a larger mount for this scope or at least looking at the Mewlon 210 as a lighter option for your mount.Answer by: Chris Hendren on Mar 28, 2016 10:42:00 AMI have a Sky-Watcher AZ-EQ6 GT Mount. What would I need to attach the Mewlon 250CRS to that mount?Question by: Gary on Jul 30, 2015 7:37:00 PMThe Mewlon 250 CRS uses tube rings w/ 125mm hole spacing, so you would need one of the BT tech XL dovetail plates to convert to Losmandy (D-series) format. The AZ-EQ6 comes with a dual saddle that accepts D-series plates, so the BT Tech plate for the Mewlon will then slide into the saddle. You will need at least 3 counterweights and possibly 4 to fully balance this scope.Answer by: Chris Hendren (Admin) on Aug 3, 2015 6:37:00 PM
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