What does the Explore Scientific 0.8x Focal Reducer do to my telescope's focal ratio?
The Explore Scientific 0.8x Focal Reducer multiplies your telescope's native focal ratio by 0.8. For example, if you have an f/7 refractor, using this reducer will convert it into a faster f/5.6 imaging system (7 x 0.8 = 5.6). This allows for shorter exposure times and a wider field of view.
How do I achieve the correct 55mm spacing with the Explore Scientific 0.8x Reducer?
The 55mm back focus is the required distance from the shoulder of the reducer's threads to your camera's sensor. This is easily achieved with most cameras:
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DSLR/Mirrorless Cameras: A standard T-ring for your camera model is typically all that is needed, as the combination of the camera's flange distance and the T-ring height equals 55mm.
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Dedicated Astronomy Cameras: You will need to use a combination of M42 extension tubes to build up the distance from your camera's sensor to the reducer. Check your camera's documentation for its sensor depth to calculate the required extension length.
Is the Explore Scientific 0.8x Reducer compatible with my f/8 refractor?
This reducer is optically optimized for refractors in the f/5 to f/7 range. While it may thread into an f/8 or slower telescope, performance is not guaranteed. Using it outside the recommended range can lead to field curvature or other aberrations, particularly at the edges of the image.
Will the Explore Scientific 0.8x Reducer work for visual observing?
No, this is an imaging-only accessory. Focal reducers are designed to project a corrected, flat image plane directly onto a camera sensor. They are not designed to work with eyepieces and will not reach focus for visual use.
How will this 0.8x reducer help me image the Andromeda Galaxy (M31) with my 80mm f/6 refractor?
An 80mm f/6 refractor has a 480mm focal length. The Explore Scientific 0.8x Reducer will shorten this to 384mm (f/4.8). This wider field of view is crucial for fitting the entire 3-degree span of the Andromeda Galaxy (M31) onto a camera with an APS-C or smaller sensor, which would be impossible at the native focal length.
Can I use this reducer to capture the full extent of the North American Nebula (NGC 7000) with a 102mm f/7 refractor?
Yes. A 102mm f/7 refractor has a 714mm focal length. The Explore Scientific 0.8x Reducer brings this down to about 571mm (f/5.6). This reduction is essential for capturing the sprawling expanse of the North American Nebula (NGC 7000) and the adjacent Pelican Nebula (IC 5070) in a single frame, especially with popular APS-C sized sensors.
