The new full frame reducer Askar FRA400 F3.9 reduces the effective focal length of the telescope by a factor of 0.7x. The original apo f/5.6 becomes an apo f/3.9. Its exposure time is noticeably shorter, reduced by about 50%. The field of view becomes considerably larger.
| Carrier | Description | Estimated Delivery | ||
|---|---|---|---|---|
 |
Home delivery - International | Home delivery - International |
Wednesday, 18 December - Wednesday, 25 December |
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Home delivery - International
Home delivery - International
Estimated delivery:
Wednesday, 18 December - Wednesday, 25 December
F3.9 flattener reducer for Askar FRA400/500
The new full frame reducer Askar FRA400 F3.9 reduces the effective focal length of the telescope by a factor of 0,7x. The original apo f/5.6 becomes an apo f/3.9. Its exposure time is noticeably shorter, reduced by about 50%. The field of view becomes considerably larger.
The FRA400Red was developed for use with the FRA400 and FRA500 flat field refractors and offers good correction with these telescopes, even when using full size sensors. The working distance from the M48x0.75 thread to the camera sensor is 55 mm. The camera adapter is equipped with a 2" filter thread.
General features:
The ASKAR full-frame 0.7x focal length reducer improves the focal ratio of the FRA400 and FRA500 from f/5.6 to f/3.9, halving the exposure time
♦ The reducer provides a corrected image field up to full-frame size format
screw connection through the M68x1 thread on the FRA400 focuser
focal length is reduced from 400 mm to 280 mm resp. from 500 mm to 351 mm for a larger field of view
♦ Working distance 55 mm from the M48x0.75 connection thread
♦ 2" filter thread available on the connection adapter
Flattening reducer F3.9 for Askar FRA400/500
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