What is the main advantage of the HOYA FCD100 glass in the ED80 refractor?
The primary advantage of HOYA FCD100 extra-low dispersion (ED) glass is its ability to suppress chromatic aberration, or false color. This results in sharper, higher-contrast images with true color fidelity, eliminating the purple halos often seen around bright stars in less-corrected telescopes.
What is the focal length and f-ratio of the ED80 when using the 0.8x reducer?
When the 0.8x reducer is attached, the ED80's effective focal length is shortened from 480mm to 384mm. This also makes the optical system faster, changing the focal ratio from f/6 to f/4.8, which significantly reduces exposure times needed for deep-sky astrophotography.
How do I connect my DSLR or astro camera to the 0.8x focal reducer?
The reducer is designed with a standard back focus of 55mm (+/- 2mm) and is threaded to accept a standard 42mm T-ring (M42x0.75). You will need a T-ring specific to your camera's brand (e.g., Canon, Nikon, Sony) to attach it to the reducer, followed by any necessary spacers to achieve the correct 55mm distance to your camera's sensor.
Is the 7.5 lb ED80-FCD100 suitable for a lightweight portable mount?
Yes, absolutely. At just 7.5 lbs, the ED80 optical tube is an excellent match for portable German equatorial mounts like the Explore Scientific iEXOS-100 or Sky-Watcher Star Adventurer GTi. This combination creates a powerful and easily transportable setup for wide-field imaging from dark sky locations.
Can I use this ED80-FCD100 bundle to image large targets like the Andromeda Galaxy (M31)?
Yes, this bundle is ideal for large targets. With the 0.8x reducer, the 384mm focal length provides a wide field of view that can easily frame the full extent of the Andromeda Galaxy (M31), the Pleiades (M45), or large nebulae like the Orion Nebula (M42), especially when paired with a camera that has an APS-C or larger sensor.
What makes the 2.5" hexagonal focuser on the ED80 special?
The 2.5" hexagonal focuser provides a more rigid and stable drawtube than traditional round Crayford focusers. This design significantly reduces flex and tilt, especially when supporting heavier imaging equipment up to its 10 lb capacity. This ensures the camera sensor remains perfectly perpendicular to the optical axis for sharp stars across the entire frame.
