Astro-Tech Dedicated 0.8x Reducer/Field Flattener for the AT102ED Refractor (#AT102EDRF)
If you're using the Astro-Tech AT102ED refractor for astrophotography, this dedicated 0.8x reducer/field flattener is the natural next step. Designed specifically for the AT102ED (model year 2017 and newer), it shortens your focal length, speeds up your system, and flattens the field for sharper stars across most DSLR and APS-C sensors.
A Purpose-Built Match for the AT102ED
This isn’t a one-size-fits-all flattener. The Astro-Tech AT102EDRF is custom-engineered to match the optical curve and focal length of your AT102ED. It threads directly into the focuser, locks into place securely, and delivers consistent results without any guesswork.
Once installed, it reduces your telescope’s focal length from 713mm to 571mm, transforming your f/7 system into a faster f/5.6 astrograph. That wider field and faster speed are ideal for capturing large nebulae, galaxy groupings, or wide-field star clouds.
Honest Optics for Real Cameras
The AT102EDRF also corrects for field curvature—one of the most common problems in refractor astrophotography. On smaller sensors like APS-C, this reducer/flattener delivers clean, round stars across the entire frame.
However, it’s important to note that while this flattener does significantly reduce field curvature, it will not fully flatten the field on a full-frame sensor. At this price point and size, that level of performance simply isn't possible. Users with full-frame cameras should expect some softening at the corners. For most APS-C sensors, results are sharp, flat, and highly satisfying.
Designed for Simplicity
The reducer threads directly into the AT102ED focuser. On the telescope side, the 2" barrel is threaded to accept standard 2" filters, so you can use your favorite light pollution or narrowband filters without needing a filter drawer.
On the camera side, the reducer ends in standard M42x0.75 T-threads, ready to accept your DSLR or mirrorless camera via a T-ring. The back focus is 55mm from the reducer shoulder to the sensor—exactly what you need for most DSLR bodies.
Observing Tip
If you're shooting from suburban skies, add a 2" broadband or dual-narrowband filter right into the reducer before mounting your camera. This keeps your imaging train short and clean—no filter drawer required—and helps improve contrast in emission nebulae or galaxy fields.
Cloudy Nights Community Feedback
Currently, no specific user reviews for the AT102EDRF have been posted to Cloudy Nights. If you're using this reducer/flattener with your AT102ED, we’d love to hear about your imaging results and help other users make informed decisions.
Final Thoughts
The AT102EDRF is a no-fuss, cost-effective way to bring faster, flatter imaging performance to your AT102ED. It won’t flatten the corners of a full-frame sensor—but for APS-C cameras, it turns your refractor into a wide-field imaging machine. Designed to fit, priced to please, and built to deliver.
