WHAT IS COMA? It’s not some sort of astronomical state of unconsciousness. It’s an optical aberration. Precisely defined, coma is a distortion in which the image of a star cannot be focused to a point, but takes on the shape of a comet. Worst yet, the majority of telescope optical systems, including the popular Schmidt-Cassegrain, have it to one degree or another.

THIS SIDE-BY-SIDE COMPARISON TELLS THE TALE. Two images, one camera, one night, and no image processing*. Two very different results. Just look at the magnified view from the Schmidt-Cassegrain on the left. Notice the crescent-shaped distortion of the star images caused by coma. Now look at the magnified image of the same stars from the LX200ACF (Advanced Coma Free** system) and you will immediately see advantages of the ACF optical system. Sharp, round stars without coma. Sharp from the center all the way to the edge of this wide field.

Once, you would have had to spend tens of thousands of dollars for an aplanatic optical system (a fancy term for coma-free). Now that Meade has made the Advanced Coma Free optical system, this level of performance is affordable to the amateur.

*The camera was a Canon 5D Digital SLR with a full 35 mm sensor. All of the above comparisons were taken using the original full frame images without any processing. The above images of M44 were taken by Jack Newton. See for yourself by downloading the two images and viewing them at 100% screen resolution from Meade.com.

**The Advanced Coma Free design is an aplanatic optical system that uses a hyperbolic secondary mirror with a corrector-lens-and-spherical-primary-combination that performs as one hyperbolic element. Its optical quality is equal to that which are known as Ritchey-Chrétien.