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Starizona Nexus 0.75x Newtonian Focal Reducer/Coma Corrector - NEXUS-075

Starizona Nexus 0.75x Newtonian Focal Reducer/Coma Corrector - NEXUS-075

Turn your Newtonian telescope into a fast, high-quality astrographic instrument with the Starizona Nexus focal reducer.

Newtonian telescopes require a coma corrector in order to give sharp stars over a large field of view, but most coma correctors keep the telescope's native focal ratio or even make the scope slower. The Nexus instead acts as a coma corrector and also provides a 0.75x focal reduction factor. This turns a common f/4 Newtonian into an f/3 system, giving a larger field of view and reducing exposure times by a factor of 1.8x.

The Nexus incorporates extra-low dispersion (ED) glass in a sophisticated optical design that gives performance equal to the best coma correctors while decreasing, instead of increasing, the focal length. The Nexus is also designed to be Par focal, so it does not change the original focal point of the telescope. The corrected image circle is 28mm, accommodating camera sensors up to APS format. While nominally designed for the popular commercial f/4 imaging Newtonians, the Nexus can work with Newtonians as fast at f/3.

Back focus requirement for the Nexus is 55mm, matching the common standard for most coma correctors, field flatteners and focal reducers. This distance allows for the use of DSLRs as well as mirrorless cameras and most astronomical CMOS and CCD cameras. The Nexus has M48 threads on the camera side. The barrel of the Nexus is a standard 2" diameter to fit most focusers. On the telescope end are M48 threads for a standard 2" filter.

Specifications
  • Focal Reduction Factor: 0.75x
  • Image Circle:  28mm (APS format)
  • In-Focus Required: None (Par focal)*
  • Back focus: 55mm
  • Camera Threads: M48 x 0.75
  • Filter Threads: M48 (2" mounted)
  • Barrel Size: 2"
  • Overall Length: 3.14" (80mm)
  • Weight: 0.74 lbs (335g)

* Some slower Newtonians that were originally intended for visual use will not reach focus with some cameras using the stock focuser. The Nexus preserves the original focus point of the telescope, so if the camera can reach focus without the Nexus it will reach focus with it. However, note that the Nexus (and most other coma correctors) require a 55mm Back focus. This means the camera has to be able to focus with that much Back focus. A CMOS camera that has a Back focus of 17.5mm, for example, might reach focus on a certain Newtonian but would not when the Back focus is extended to 55mm as required by a coma corrector. Most commercial f/4 Newtonians are designed with plenty of Back focus for a coma corrector because they are intended for photography. But some slower Newtonians intended for visual use do not have enough Back focus for a coma corrector and camera. Please feel free to contact us if you are unsure of your telescope's compatibility.
$114.09

Original: $325.97

-65%
Starizona Nexus 0.75x Newtonian Focal Reducer/Coma Corrector - NEXUS-075

$325.97

$114.09

Product Information

Shipping & Returns

Description

Turn your Newtonian telescope into a fast, high-quality astrographic instrument with the Starizona Nexus focal reducer.

Newtonian telescopes require a coma corrector in order to give sharp stars over a large field of view, but most coma correctors keep the telescope's native focal ratio or even make the scope slower. The Nexus instead acts as a coma corrector and also provides a 0.75x focal reduction factor. This turns a common f/4 Newtonian into an f/3 system, giving a larger field of view and reducing exposure times by a factor of 1.8x.

The Nexus incorporates extra-low dispersion (ED) glass in a sophisticated optical design that gives performance equal to the best coma correctors while decreasing, instead of increasing, the focal length. The Nexus is also designed to be Par focal, so it does not change the original focal point of the telescope. The corrected image circle is 28mm, accommodating camera sensors up to APS format. While nominally designed for the popular commercial f/4 imaging Newtonians, the Nexus can work with Newtonians as fast at f/3.

Back focus requirement for the Nexus is 55mm, matching the common standard for most coma correctors, field flatteners and focal reducers. This distance allows for the use of DSLRs as well as mirrorless cameras and most astronomical CMOS and CCD cameras. The Nexus has M48 threads on the camera side. The barrel of the Nexus is a standard 2" diameter to fit most focusers. On the telescope end are M48 threads for a standard 2" filter.

Specifications
  • Focal Reduction Factor: 0.75x
  • Image Circle:  28mm (APS format)
  • In-Focus Required: None (Par focal)*
  • Back focus: 55mm
  • Camera Threads: M48 x 0.75
  • Filter Threads: M48 (2" mounted)
  • Barrel Size: 2"
  • Overall Length: 3.14" (80mm)
  • Weight: 0.74 lbs (335g)

* Some slower Newtonians that were originally intended for visual use will not reach focus with some cameras using the stock focuser. The Nexus preserves the original focus point of the telescope, so if the camera can reach focus without the Nexus it will reach focus with it. However, note that the Nexus (and most other coma correctors) require a 55mm Back focus. This means the camera has to be able to focus with that much Back focus. A CMOS camera that has a Back focus of 17.5mm, for example, might reach focus on a certain Newtonian but would not when the Back focus is extended to 55mm as required by a coma corrector. Most commercial f/4 Newtonians are designed with plenty of Back focus for a coma corrector because they are intended for photography. But some slower Newtonians intended for visual use do not have enough Back focus for a coma corrector and camera. Please feel free to contact us if you are unsure of your telescope's compatibility.

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