NavList:

Dear Noell,

I don't now how to evaluate or compare the glasses. (All modern telescope glasses are free from chromatic aberration and let sufficient light in).

Inverting feature is irrelevant for me. Some people say that it is inconvenient to them, but from my point of view it is completely irrelevant. You just need a little practice to get accustomed to it. What I like about it is the wide field of view, light weight, and the presence of cross wires.

The field of view is about the same as that of a modern 8x binocular, or a similar prismatic telescope. But prismatic telescopes are very heavy, and bulky. They are heavy because they contain prisms, and the sole purpose of those prisms is to turn the image and to make them straight rather than inverting. The last feature is irrelevant from my point of view.

The role of cross wires have been discussed in this list some time ago. It is hard to say how exactly they help, perhaps the effect is purely psychological. They are supposed to help you to keep the object near the center of the field of view, and also to focus your telescope in certain circumstances.

Most people who tried the SNO-T 7x scope agree with me, except those for whom the straight (not inverted) image is important.

I have to add that all this is based on my observations which are mostly made from land. On a small boat I prefer a zero magnification tube. It is very hard to keep the image within your field of view in a rolling boat with a 7x or 8x telescope.

Alex.