
30-12-2009, 10:36 AM
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Registered User
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Join Date: Mar 2009
Location: Elk Grove CA USA
Posts: 1
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Takahashi's New ED Corrector
Hello all you Takahashi users! I thought you all might be interested in Tak's new ED Corrector for the M250 and 300's! All I can say is, WOW !!!
μ-250CR Corrector System Takahshi has been producing the Mewlon-250 and 300 Dall-Kirkham reflectors for 20 years. They have proven to be excellent visual telescope and small field imaging instrument when used with the dedicated reducer/flattener.
Now, Takahashi has developed in line triplet ED corrector for the Mewlon-250 and 300. These proprietary correctors eliminate off-axis coma, flatten the field and slightly reduce the focal length for these telescopes. The result is a system to offer corrected fields at three different focal lengths. This tri-focal system can make every Mewlon-250 and 300 into excellent versatile imaging and visual telescopes. They are f/10, f/7.3 or f/15 depending upon the configuration used. This tri-focal potential will cover a variety of imaging needs with just one instrument.
The corrector is permanently located in the baffle tube which is easily exchanged by the user. It produces a 44mmø circle perfect for imaging or observing. Or it can be ordered in a new Mewlon-CR 250 or Mewlon-CR300
Augmenting the Mewlon CorrectorCR is the 0.73 ReducerCR and 1.5x ExtenderCR. Each enhances the MewlonCR System. The ReducerCR changes the μ-250 to an f/7.3 wider field imager yet with the larger image scale for larger objects. While the ExtenderCR produces a very large image scale for the very small objects.
Stellar sizes in the center are 2 microns for the C-F line and 3 microns for the g line, well beyond the diffraction limit. This image size is suitable for any CCD camera or digital SLR with an appropriate sized sensor.
Mewlon-CR 250 for μ-250
Effective focal ratio f/10
Effective focal length 2500mm
Image circle 44mm ø
Imaging circle 1º
Reducer-CR 0.73x
Effective focal ratio f/7.3
Effective focal length 1825mm
Image circle 35mm ø
Imaging circle 1.1º
Extender-CR
Effective focal ratio f/15
Effective focal length 3780mm
Image circle 44mm ø
Imaging circle .66º
Mewlon-CR for μ-300
Effective focal ratio f/9.9
Effective focal length 3780mm
Image circle 40mm ø
Imaging circle 0.77º
Reducer-CR
Effective focal ratio f/7.2
Effective focal length 2960mm
Image circle 35mm ø
Imaging circle 0.92º
Extender-CR
Effective focal ratio f/14.9
Effective focal length 4475mm
Image circle 44mm ø
Imaging circle 0.56º
James Edwards
Elk Grove CA, USA
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