What is the main benefit of using the 0.8x reducer with the Askar 185APO?
The primary benefit is speed. By reducing the focal ratio to f/5.6, you can gather the same amount of light in a significantly shorter time compared to the telescope's native f/7. This allows for higher quality images with less total exposure time and reduces demands on your mount's tracking accuracy. It also provides a wider field of view for imaging large celestial objects.
How does the Askar 185APO 0.8x Reducer achieve a flat field?
The reducer uses a 4-element quadruplet optical design. This sophisticated lens arrangement is engineered not only to reduce the focal length but also to correct for off-axis aberrations like field curvature and coma, which are common in fast optical systems. This ensures that stars are sharp and round from the center of the image to the corners of a full-frame sensor.
Is the 55mm back focus on the 185APO reducer compatible with my DSLR?
Yes. The standard 55mm back focus is the industry standard for DSLR and mirrorless cameras when using a typical T-ring adapter. You can attach your camera directly to the reducer's M48 thread with the appropriate T-ring for your camera model and achieve perfect spacing without extra calculations.
Can I use 2-inch filters with the Askar 185APO 0.8x Reducer?
Yes. The reducer features a built-in M48×0.75 female thread on the camera side, which is the standard for 2-inch astronomy filters. You can thread your filters directly into the reducer itself, placing them at an optimal position within the light path.
How will the 185APO 0.8x Reducer change my framing for a large target like the Andromeda Galaxy (M31)?
With the reducer, the 185APO operates at a 1036mm focal length. This wider field of view is much better suited for capturing the full extent of massive objects like the Andromeda Galaxy (M31) or the Veil Nebula complex on a full-frame sensor. Without the reducer, you would likely need to create a multi-panel mosaic to capture these targets in their entirety.
I have a cooled camera with a 20mm filter wheel. How do I achieve the 55mm back focus with the 185APO reducer?
The 55mm back focus is measured from the M48 thread flange on the reducer. You'll need to account for the light path consumed by your equipment. If your camera sensor's back focus is 17.5mm and your filter wheel is 20mm thick, you have used 37.5mm of the available 55mm. You would need 17.5mm of M48 extension tubes between the reducer and your filter wheel to achieve the correct spacing.
