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Antares 2" 0.7x Focal Reducer

4.0 (1 Reviews) Read Reviews Write Review
Brand Antares
Part Number FR2-0.7
Availability available

Product Info

Manufacturer Description

Antares' 2" 0.7x focal reducer screws on to any accessory (such as eyepieces, camera adapters, etc.) that accepts standard 2" threaded filters and provides a nominal reduction of 0.7x. Use of this focal reducer effectively reduces the focal ratio of your telescope, resulting in a wider field of view and significantly shortened exposure times for astrophotography. For example, use of this reducer will convert an f/10 telescope into an f/7 scope.

The 2-element reducer features fully multi-coated optics in a black-anodized aluminum filter cell. This focal reducer will work well for visual use too when coupled with the right kind of eyepieces and telescopes (it is not recommended for very fast scopes or very wide angle eyepieces for visual applications). However, it does not have external 2" female threads so you cannot screw/stack additional 2" filters on to this reducer.

The actual reduction will vary a little over or under 0.7x depending on exactly where the focal reducer is placed in the optical path. The focal length specification of this reducer is 220mm. Hence, the "working distance" of this specific reducer is 66mm, i.e., this reducer will provide a reduction of 0.7x when the center of its lens assembly is placed 66mm from the focal plane of the eyepiece or imaging device. Move the focal reducer closer to the eyepiece/camera and its reduction factor will increase. Move it away and the reduction provided will decrease.

By using additional spacers or extension tubes (sold separately), you can vary the amount of reduction you obtain with this reducer as follows:

Extra Spacer Length
Nominal Reduction Provided
0" / 0mm
0.25" / 6.4mm
0.5" / 12.7mm
0.75" / 19.1mm
1" / 25.4mm

Note that the use of any optical element like barlows and focal reducers changes the focus point of your telescope, requiring additional in-focus or out-focus travel. The exact amount of focus travel required will depend on the optics and mechanics of your specific set-up (telescope, diagonal (if used), barlow/reducer, and eyepiece). Hence, be aware that you may not be able to reach focus with all eyepieces or in all configurations with a given barlow/reducer.

Total length (including external thread) = 22mm (0.86"); Total length (excluding external thread) = 18mm (0.70"); Clear Aperture = 39mm (1.54"); Weight = 3.3 oz.; Made in Canada.


4.0 (Based on 1 Reviews) 100% of reviewers recommended this product.
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    1. jlummel

      jlummel New Member

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      User Notes:
      Review by jlummel of Windy Northern Arizona.
      Oct 12, 2011

      4.0 Versatile focal reducer


      Quality Lenses,Easy to Use


      Can't add a filter


      I bought one of these focal reducers to use with a Canon DSLR for astrophotography. I've yet to use it for that!

      However I found a better use for it in the meantime. I recently purchased a 100

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

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