What is the purpose of the Orion Optics UK 85mm fixed adaptor ring?
This ring is a precision spacer. Its sole function is to connect to an 85mm threaded component in your optical train and provide exactly 25mm of back focus distance. This ensures your camera's sensor is positioned at the precise distance required by your telescope's field flattener or coma corrector for optimal performance.
How do I know if I need exactly 25mm of back focus for my Orion Optics UK telescope?
The required back focus distance is determined by the specific corrector or flattener you are using, not the telescope itself. You should consult the technical documentation for your Orion Optics UK corrector to confirm if it requires a 25mm spacing for your imaging setup.
Can I use this 85mm adapter with other brands of telescopes or correctors?
While it may be physically compatible with any system that uses an 85mm thread, this adapter is specifically machined to provide the 25mm back focus required by certain Orion Optics UK components. Using it with other systems may not place your sensor at the correct distance, potentially degrading image quality.
Why is this Orion Optics UK adapter a fixed 25mm length instead of being adjustable?
A fixed-length adapter offers superior mechanical stability. Unlike adjustable spacers, which can introduce sag or tilt from their multiple threaded parts, a single-piece fixed adapter ensures a rigid, perfectly aligned connection. This is critical for preventing misshapen stars, especially with heavier cameras.
Will this 85mm adapter introduce any tilt into my imaging train?
No. This adapter is precision-machined as a single, solid component to prevent tilt. Its primary advantage over adjustable or stacked solutions is the guarantee of a square, rigid connection between your corrector and the next element in your imaging train.
What imaging setup would require a 25mm spacer like this one?
An example setup would be connecting an Orion Optics UK coma corrector with an 85mm output thread to an off-axis guider or filter wheel that leaves a remaining 25mm distance requirement to reach the camera sensor's focal plane. This adapter fills that specific gap precisely.
