Astro-Tech 0.8x reducer/field flattener for Astro-Tech AT115EDT triplet apo refractor


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This economical 0.8x focal reducer and field flattener is designed specifically for astrophotography with the Astro-Tech AT115EDT 115mm f/7 triplet apo refractor. 
Our Product #: ATREDT15
Astro-Tech Product #: ATREDT15

Product Description

This Astro-Tech #ATREDT15 0.8X focal reducer/field flattener is designed specifically for prime focus astrophotography with the Astro-Tech AT115EDT ED triplet apo. While it may also work well with other brands and models of f/7 refractors that use a 2" focuser, its performance with other scopes is not guaranteed.

The fully-multicoated Astro-Tech #ATREDT15 reducer/flattener converts the 805mm focal length f/7 Astro-Tech AT115EDT refractor into a 644mm f/5.6 system for faster and wider field astronomical and terrestrial photography. 

In addition to reducing the focal length of the telescope and thereby increasing the photographic speed, the #ATREDT15 flattens the normal field curvature inherent in all refractors. This provides images that are sharply focused out to the corners of DSLR 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 #ATREDT15 reducer/flattener can be connected to your AT115EDT in two different ways. The first is the most secure for extended imaging sessions. The 2" barrel of the reducer is threaded at the top, as can be seen in the feature image above. If the 2" accessory adapter is unthreaded from the camera angle adjuster on the scope, the reducer can be threaded onto the camera angle adjuster in its place for the most solid and secure connection.
In the second connection method, for casual imaging, the 2" barrel of the #ATREDT15 can simply be slipped into the scope's 2" focuser in place of your star diagonal. The 2" telescope-side barrel of the reducer is threaded for standard 2" filters and has a safety groove. 

The camera side of the #ATREDT15 reducer has standard 42mm 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 DSLR camera bodies. 

Tech Details

Weight 9 oz.
Warranty 1 year


Review by:
I purchased this hoping it would work well on my AT111 and I was not disappointed. It has been a perfect match. Stars are very sharp out to the edge and it is added another dimension to my favorite telescope. Build quality is outstanding and the service from Astronomics was great as usual. (Posted on 4/21/2020)
Review by:
Works well with my AT115 and ASI 294mc-pro. The optics are clear and the field is flat to 85% of the field of view. The focal reduction is nice for capturing extended objects like the Veil and M31. I like that it screws into the focuser for a secure connection. (Posted on 12/31/2018)
Review by:
I use this reducer/flattener with my AT115edt and ASI 294mc-pro camera (and baader adjustable spacer). It works well with the camera and is optically very good. It has a flat field for about 85% of the field of view. The .8 reduction is very nice for fitting extended objects onto the sensor. I like that it screws into the AT115 focuser for a solid connection with no fixture movement. (Posted on 12/31/2018)
Review by:
This focal reducer is well made and works well. It is a good fit. Images are clear and sharp. (Posted on 12/27/2018)
Review by:
I have an AT-115 EDT so I purchased the .8x focal reducer/field flattener for better photo quality. I was very pleased with the results. It is made just for the AT-115 EDT. It brought the AT -115 from F7 to F5,6 . Very clear optics and well worth the money. (Posted on 11/2/2018)
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