Product Code: 1758116

Sky-Watcher 0.77 Reducer / Flattener for Esprit-150ED

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1x Sky-Watcher 0.77 Reducer / Flattener for Esprit-150ED Sorry, there are no more available.

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As a high-powered stargazing tool, this 0.77 Reducer / Flattener from Sky-Watcher is a must-have for astrophotographers utilising the Esprit-150ED Professional Super APO Triplet Refractor OTA. In short, the field flattener accurately corrects the inherent spherical aberration of curved lenses. Without such a tool, image quality is lessened as the frame appears distorted at the edges of the field of view. When used as a focal reducer, you are afforded a key reduction in the focal ratio of the scope. By doing so, you are left with a wider field of view with shortened exposure time, allowing for more images to be captured in a shorter amount of time without affecting their overall quality.

Sky-Watcher 0.77 Reducer / Flattener for Esprit-150ED Key Features:

  • Solely compatible with the Esprit-150ED Professional Super APO Triplet Refractor OTA
  • Specifically suited to astrophotographers and astroimaging
  • Promises to essentially eliminate spherical aberrations
  • Actively shortens the focal ratio from f7 to f5.4
  • 68% reduction in exposure time
  • Compatible with APS-C and full frame cameras
  • Full frame camera produces 2.54 x 1.7° field of view
  • APS-C crop sensor produces 1.66 x 1.11° field of view
  • Consists of a sizeable 36mm imaging circle
  • Produces a fully illuminated
  • 90mm or 55mm back-focus (with back focus spacer and M48 ring)
  • Implements a 2” filter thread
  • Suited to a vast array of filters such as moon, polarizing, and light pollution

What’s in the box?

  • 1 x Sky-Watcher 0.77 Reducer / Flattener for Esprit-150ED
  • 1 x Back Focus Spacer
  • 1 x M48 Thread Adapter
  • 2 x Threaded Cap
  • Limited 2-Year Warranty


Does the Sky-Watcher 0.77 Reducer / Flattener come equipped with end caps?

This astrophotography tool does come equipped with green anodised aluminium screw-on end caps.

How many optical elements are implemented within the design?

The 0.77 Reducer / Flattener utilises three key optical elements within its internal design.

How heavy is this device?

The Sky-Watcher 0.77 Reducer / Flattener weighs 910g with threaded caps attached.

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Product Specification

Type Focal Reducer/Field Flattener
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Product Code: 1758116-wex Manufacturers Part Number: 20096