The Orion 0.8x Reducer-Flattener for EON 115mm ED Triplet Refractor will ensure wonderfully sharp photographs edge to edge with our premium EON 115 Apo. All refractors produce some amount of field curvature, which results in elongation of star images at the edges of the image frame. An optical flattener is recommended to correct for this. The 0.8x Reducer-Flattener provides excellent field correction (flattening), yielding sharp stars out to the edge of even a full-frame camera sensor. It also reduces the effective focal length of the EON 115 by 20 percent - from 805mm to 644mm (f/7.0 to f/5.6) - yielding a wider field and brighter images, and allowing shorter exposure times for astrophotography.
Designed solely for photographic use, the 0.8x Reducer-Flattener threads directly onto the EON's focuser drawtube after removal of the accessory collar. This threaded connection ensures a secure fit that will not introduce flexure. The male threads on the camera side of the 0.8x Reducer-Corrector are 48mm in diameter. They are wider than standard 42mm T-mount threads. The wider 48mm aperture reduces the likelihood of vignetting of the image, especially when using a full-frame camera sensor.
The 0.8x Reducer-Flattener has a 55mm back focus distance. To produce a focused image, your camera's sensor must be positioned 55mm from the housing flange. Most DSLR cameras, when used with a T-ring, have the requisite 55mm back focus distance. For astronomical cameras, which have their sensor closer to the front opening of the camera, one or more spacer rings (sold separately) will be needed between the camera and the Reducer-Flattener to achieve the 55mm requirement. Consult your camera's manual to determine how far back the sensor is recessed. Subtract that number from 55mm to get the length of spacing needed to reach 55mm back focus distance.
The optics of the 0.8x Reducer-Flattener are fully multi-coated for maximum light transmission. Compatible with EON 115mm ED equipped with 2.5" R&P focuser only. Not compatible with older EON 115mm ED model with 3" Crayford focuser.