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SharpStar 94EDPH 0.8x Focal Reducer
This dedicated 0.8x focal reducer transforms the SharpStar 94EDPH into a fast f/4.4 imaging system, using a 4-element optical design to deliver a corrected 50mm image circle. The standard 55mm back focus simplifies camera and accessory integration, while the reducer itself has a maximum outside diameter of 88mm.
A Faster, Wider Field: The 4-Element Design for f/4.4 Imaging
By reducing the focal ratio to f/4.4, this accessory significantly shortens required exposure times, allowing you to gather more signal on faint targets in a single session. The wider field of view also makes it possible to frame large celestial objects, like the Andromeda Galaxy (M31) or the North American Nebula (NGC 7000), in their entirety.
The 4-element optical layout is engineered to correct for optical aberrations across the field, ensuring that stars remain sharp and round from the center to the edge of the frame. This corrective power is essential for maintaining the high image quality of the 94EDPH's triplet objective.
Full-Frame Ready: 50mm Image Circle and 55mm Back Focus
The reducer's optical design produces a fully illuminated and corrected 50mm image circle. This generous field is large enough to cover full-frame sensors (like the Sony a7 series or dedicated cameras with IMX571/IMX455 sensors) without vignetting, maximizing the imaging potential of the telescope.
A standard 55mm back focus distance simplifies the process of connecting most DSLRs, mirrorless cameras, and dedicated astronomy cameras along with their associated filter wheels or off-axis guiders. This industry-standard spacing ensures broad compatibility with your existing imaging train.
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Will the SharpStar 94EDPH reducer cover my full-frame camera sensor?
Yes. The reducer produces a 50mm image circle, which is more than large enough to fully illuminate a standard 36x24mm full-frame sensor without vignetting.
How does this 0.8x reducer help when imaging a target like the Heart Nebula (IC 1805) with the 94EDPH?
The reducer widens the field of view, allowing you to capture the entire expanse of large targets like the Heart Nebula in a single frame. It also speeds up the optics to f/4.4, reducing the exposure time needed to capture faint nebulosity.
What is the back focus of the SharpStar 94EDPH 0.8x reducer?
The required back focus is 55mm. This is a standard distance for many imaging setups, making it easy to integrate with accessories like T-rings, filter wheels, and off-axis guiders.
What does the 4-element design in the SharpStar 94EDPH reducer do?
The 4-element design acts as both a reducer and a field flattener. It is optically matched to the 94EDPH telescope to ensure stars are sharp and round across the entire 50mm image circle, correcting for field curvature and other off-axis aberrations.
What is the final focal ratio of the SharpStar 94EDPH when using this reducer?
This 0.8x reducer converts the SharpStar 94EDPH into a fast f/4.4 imaging system.
Is this reducer compatible with other telescopes besides the SharpStar 94EDPH?
This reducer is specifically designed and optically matched for the SharpStar 94EDPH telescope. Using it with other telescopes is not recommended as it may not provide a fully corrected field.
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| Reduction Factor |
0.8x |
| Final Focal Ratio |
f/4.4 |
| Optical Design |
4 Elements |
| Image Circle |
50mm |
| Back Focus |
55mm |
| Maximum Outer Diameter |
88mm |
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Askar 1-Year Warranty
