Coma Aberration in the Newtonian Telescopes

By Santiago Roland - Los Molinos Observatory IAU CODE 844 (OALM) - Amateur Astronomers Association (AAA)

Montevideo - Uruguay

10 Jan, 2006.


 

Introduction - The coma aberration of a newtonian telescope is inevitable. But it can be reduced by increasing the f/number of the telescope. The coma elongates stars at the edge of the field and this elongation is bigger when the telescope is faster. This means, small focal ratios.

I decided to study the behavior of coma and I did it mathematically. The way of approaching this problem is let some rays coming from a star, go to the main mirror and reflected to the focal plane. I studied the reflection of this rays and the image formed in the focal plane.

Later with this tool, I made diagram spots that shows how coma is formed and how big it is.

 


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