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Old 20-07-2016, 01:18 PM
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mental4astro (Alexander)

mental4astro is offline
Join Date: Jun 2008
Location: sydney, australia
Posts: 4,618
Hi Steve,

The Revolution Imager is great with an 8" SCT like yours. I use my camera regularly with my C8.

A focal reducer is not a "must have" with SCT's. It is a big help though as the field of view given by the camera in a 2000mm focal length scope is small. A focal reducer will increase the field of view seen by the chip.

A good focal reducer to use with it is that inexpensive 1.25" 0.5X reducer that winds into the end of eyepieces like a filter - it isn't really meant for using with eyepieces, but the turn of phrase is meant as a descriptor. One thing about the reducer is the further you set it away from the sensor chip, the wider the FOV it provides, but this in turn can mean more in-travel for the camera - not such a problem with an SCT.

If you have a short tube barlow lens, you can see how you go by replacing the barlow lens itself from the tube, and replacing it with the focal reducer. The camera you fit into the barlow tube as you would an eyepiece. This would pretty much give you the widest field of view possible with an 8" SCT. Depending on what other extension tubes you have lying about, you can experiment with different combinations and see what works best.

The focal reducer I mentioned above is not an optical match for Newtonians. The image this reducer with produce with a Newt is abysmal. It will work well with refractors too, though the faster the refractor the more challenging for the focal reducer. If you are after a focal reducer for a Newtonian, Mallincam has one.

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