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Subject: [M]: 0"lx200 vs 8"Newt
From: Gary McKenzie
Reply To: mapug@shore.net
Date: Mon Oct 20 20:57:45 1997

you wrote:

While at a star party several weeks ago, several of us were looking at =
the Veil nebula. I was using my f6.3 10" lx200 and needed an Olll =
filter just to make out its faint blur while a friend, using an 8" =
newtonian with enhanced coatings and no filter could see it with little =
difficulty. I checked it out for myself and broke into a cold sweat. =
We were using similar eyepieces and limiting magnitude was 6.5-7.0. I =
checked the collimation and it seemed good enough on the lx200. Is this =
the type of performance I should expect, or is the view better through =
the 8" for other reasons?

Rich Brenz
eyeclinic@michweb.net

Hi Rich,
in principle, YES, this is what you can expect. The 10" f6.3 has a 4"
obstruction, the 8" probably had a 1.83" or depending on focal length a
1.5". It has pretty well been established that in contrast and resolution
terms, scopes can be compared on the basis of primary size - diagonal size.
Thus:

10"-4" = 6"
8"-1.83"=6.17

also a well made newt is inherently better baffled than an sct, were you
using a dew shield? have you flocked your scope? In addition was your scope
perfectly collimated? Is your scope high quality optically? The newt may
have had a top class mirror, and you may have a run of the mill sct. If you
had compared your scope to a 6" apo, you probably would not have worried
about the comparison, yet a GOOD 8" newt will usually AT LEAST EQUAL a 6"
apo. You probably bought your scope on the basis of convenience, and
gadgets (like me :) !). I was lucky enough to get a class optic, most are
not. As someone who has ground, polished and figured 5 newts, I can verify
that a newt, when well made, craps all over an average sct and gives an apo
a run for its money!

Gary - 8" lx50 owner!!