Fast Scope - Bad Scope?

Just looking for a little nudging in the right direction on a scope purchase.

I have previously owned and used 2 dobs and a SCT being 8" f/6, 10" f/6, and 10" f/10 but now considering a 10" f/4.5 dob with a Discovery mirror.

Is the fast f/4.5 going to be dissapointing after using only f/6 and f/10 scopes in the past? Obviously I'm worried about coma and how much of the field will be crisp and "usable", especially on open clusters.

My viewing runs the full spectrum of planets, open and globular clusters, galaxies, and nebula.

My eyepieces will eventually be Naglers, Panoptics, and Radians.

Should I take the plunge or look for a slower scope?

Thanks,

Mark

For years i only used slow Newts longer than F/6, back in the 70's and 80's all the fast Newts i used gave crappy images!

But things have changed today, with much better optics, collimation tools, and center marked mirrors, it's a whole new ballgame. After owning five Starmasters all under f/4.5 i was changed from my old thinking.

A f/4.5 scope with great optics when collimated, can be a planet killer, i would aslo use a Paracorr with any Newt faster than f/6!

Chas

As Charles pointed out, at f4.5 you will want a paracorr. You will also need to use high-quality eyepieces (TV pan's or naglers, Pentax XL's or XW's, Meade 4000 UWA's, etc. Jury still out on the Meade 5000 series. Most plossls are okay also). Avoid the cheaper widefields like Konig's, Meade 4000 SWA's, 1RPD's, etc. They will have astigmatism that will be far worse than the coma, and the paracorr won't fix that.

But with good eyepieces and a paracorr, a fast newt can give outstanding images.

Jarad