Saturday, April 17, 2004
Comparing three telescopes: Vixen, Tal and Skywatcher

Last Thursday night, together with a fellow astronomer, I have been observing some objects through three different telescopes, an 8-inch Vixen Newton telescope, an 8-inch TAL Klevtzov-Cassegrain and a 10-inch Skywatcher Newton.  We compared some globular clusters (M 3, M 5 and M 13), some galaxies (M 81, M 82, M 51, M 64), some double stars (the Double Double in Lyra, Iota Cancri, Cor Caroli, the Alcor/Mizar system), Jupiter, M 44, and a planetary, M 57.

The seeing was bad, but that was the same for all three telescopes. We first compared the two 8-inch telescopes. The TAL was much better on Jupiter (more contrast) but the Vixen was definitely better with the galaxies and globular clusters. On double stars both scopes where equal. What we also liked more about the Cassegrain system is that you can sit down while observing, you are always observing from almost the same position. With the Newton the height varies a lot and also the position of the eyepiece is variable.

We also compared the 10-inch Skywatcher with the two 8-inch systems. With the globular clusters and galaxies, the 10-inch wins! Aperture rules, as always, especially with the globulars. They where all resolved (partially) in the 10 inch Skywatcher, while both 8-inch telescopes showed only very faint patches of light with only a few stars resolved against the background glow. The trick is to find the balance between aperture, quality of the scope and the amount of money you can spend for a telescope. But one thing is sure: aperture rules, even in a suburban, heavily light-polluted backyard.

Posted by Math on 04/17 at 03:15 PM | filed in: Print