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Re: 8" EQ's - Celestron Vs. Apogee

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Posted by Ed Slocomb on February 5, 2000 06:18:00 UTC

: I'm looking @ a Celestron G-8n (f/10)for $699.00 vs. an Apogee 8" Newt.(f/4)with motor drive and hand controller for $100.00 less. Why? Being new to all this, I would assume it has something to with the focal ratio, or is the Apogee just poor quality? Could someone explain to me in simple terms what focal length is, and it's importance when comparing scopes? : Thanks!

About the Celestron Gn8 and the Apogee-- The Celestron is on a heavier mount, which is a Chinese-made knock off of the Vixen Great Polaris (and probably not as good IMHO). The Apogee is on a much lighter mount.

The Celestron 8" F5 tube has a glass element at the focuser (I think) which is supposed to serve as a coma corrector/field flattener. I also suspect that it does a bit more (later).

The Apogee tube appears to be the same unit sold under many other names, all for about the same price. It is made in Taiwan. How good is it? I dunno. Consider that the Vixen 8" F4 optical tube, which is very well made, sells for roughly $1000--without the mount!

Which brings me back to the Celestron. You get the tube and mount for less than $700. Remember that coma corrector/field flattener? I suspect it also corrects for a spherical mirror. A spherical mirror is MUCH cheaper to make than a paraboloidal mirror, and if this is the case, you should consider that there are limits to what the corrector can do in addition to its other duties. Celestron may clarify this.

I hope this is not too late to be of help.

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