Astro-Tech 1X Field Flattener For Astro-Tech AT90 Triplet APO Refractor

This Astro-Tech AT90FF 1X field flattener is designed specifically for prime focus astrophotography with the Astro-Tech AT90CFT or AT90EDX ED triplet apo. While it may also work well with other brands and models of f/6 refractors that use a 2" focuser, its performance with other scopes is not guaranteed.

The fully-multicoated Astro-Tech AT90FF field flattener leaves 540mm focal length f/6 Astro-Tech AT90CFT or AT90EDX refractor in its native state, but flattens the field up to a full frame format camera.  This provides images that are sharply focused out to the corners of DSLR, CMOS, and CCD imaging chips. Stars look sharp and point-like all the way across the field in your images. You don't have to worry about photos that are sharp in the center and blurry at the edges.

The Astro-Tech AT90FF field flattener can be connected to your AT90CFT or AT90EDX using it's M63 threaded end.  This threaded end will either connect directly to the focuser drawtube, or connect to your camera angle adjuster.

The camera side of the AT90FF field flattener has 48mm T-threads to connect to a T-ring and DSLR camera body. A slip-on soft rubber cover protects the T-threads when the reducer is not in use, while a second slip-on cover is provided for the 2" scope-side barrel. Back focus is 55mm from the shoulder of the reducer to the image plane, the standard spacing for imaging devices.  The top of the field flattener will also unthread from the body exposing a 2" filter thread on the bottom of the piece you just unthreaded.  This will allow you to put 2" filters in line with your imaging train without the need for a filter drawer or filter wheel.