A high quality dual element 0.8x Field Flattener / Reducer for use with Starwave 70ED Refractor and Canon DSLR.
Will only work with a Starwave 70ED
Delivery In 1-5 Days*
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The field flattener improves the quality of star images toward the field edges and decreases the focal ratio from F6 to F4.8.
The focal length of the telescope decreases from 420mm to 336mm.
Everything you need to connect your Canon DSLR to your Starwave refractor is included in the kit.
All lenses are fully multicoated and are made from the finest optical glass, housed in a CNC machined, black anodised aluminium body.
A rubber cap is included to cover the 2" push-fit barrel, and a metal threaded M48 cap is included to cover the rear optical element.
The Canon EOS adapter has an inner ring with M48 thread. 3x small grub screws spaced 120 degrees apart are located around the edges, allowing the M48 thread to be removed from the EOS adapter. These grub screws may need to be tightened up on first use. You can check this by rotating the EOS bayonet adapter against the . Simply screw the EOS bayonet adapter onto the M48 spacer, which is already attached to the rear of the flattener. Note: A small silver indexing cross-head screw is located in the EOS bayonet adapter for use with older EOS lenses. If the EOS lens does not click into place first time, this screw can be removed and discarded for use with more modern lenses.
How does it work and why do I need it? All refractor lens systems exhibit some natural field curvature, which, while not relevant for visual observation, can be visible in photgraphic images. This field flattener/reducer has a 2" pushfit barrel which can be inserted directly into the rear focuser of your Starwave 70ED or refractor, converting it into a fast astrograph with a faster focal length and a flatter photographic field than the existing lens system alone. By reducing the focal length by a factor of 0.8x, you get a faster focal ratio, therefore exposure times are reduced by a ratio of 1:1.56 compared to the normal exposure time. In photographic terms this is expressed as a gain of +0.64EV.