At this point, the main problem in my images that really annoys me is the chromatic aberration (the purple fringe around stars). Also the field curvature of the ST80 is really bad, especially on a crop size sensor, as you begin to move away from the center of the frame.

Used Orion ED80 purchased for $340 CAD

So to achieve a considerable jump in image quality, I need to upgrade my imaging scope to an apochromatic refractor. This type of telescope allows red, green and blue light to reach focus more evenly on the focal plane.

Refractors with the best cost to image quality ratio that achieve this are the ED “doublets”. One that is really cheap and high quality is the Orion ED80. It contains an extra-low dispersion element made from FPL-53, which is one of the best glass you can get in a telescope, aside from Fluorite.

Note: The reason I didn’t buy a “triplet” refractor, is because the gain of 5 – 10% in image quality isn’t justifiable, especially when the price of these scopes is in the thousands! I rather spend my money on other equipment I desperately need.

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