ETX-90 and ETX-105EC COMPARISON Last updated: 8 March 2002

Sent:	Friday, March 8, 2002 17:25:56
From:	Marknjuli@aol.com
I have loved your site from the early days and still catch up at least
once a month. I have been into Astronomy for around 10 years and the
last 5 years of that with ETX 'S, thanks in part to your site.

Anyway, I have had the ETX-90RA, ETX-90EC, and now have the ETX-105EC.
Over the last two weeks or so I have used the 90-EC and 105-EC side by
side on several nights and thought I would share what I have found. The
views were compared at the same magnification with comparable EP's. A
13mm Nagler in the 105 @113x and an 11mm Nagler in the 90@114x. Very
good levels of magnification for both, IMHO. Also, with the Autostar
(current version) and mounted ALT/AZ.

First of all, optically they are very close. The larger aperture of the
105 wins, but both scopes are so optically excellent the differences are
subtle. For example, on Jupiter, in the 105 the GRS is slightly more
detectable, and shadow transits are a little crisper, also in GOOD
seeing an extra cloud band or two can be seen. On Saturn in the 105 I
was on two or three nights of good seeing able to see an additional moon
in the 105 with averted vision that I simply could not find in the 90. 
Otherwise the views of Saturn were indistinguishable. The most
difference I have seen in the optics is on globulars. In the 105 they
are brighter (as expected) and hence make them easier to see, which is
about all you can really hope for from scopes this size.

As for the base...  no comparasion!! The 105 is MUCH sturdier, and just
"feels" better built.
How's that for an intangable?
I havn't opened it up to see why and have no intention of doing so any
time soon!! The locks, lock easier and firmer, but that may be due in
part to being new, time will tell. In both scopes go-to's are dead-on
but the 105 does slew smoother. And here's the big surprise....

I have read complaints on your site about the noise with the 105, and
what a shock.

My 105 is nearly silent. Only at the two or three highest speeds can the
motors and gears be heard at all. Much,much quieter than the 90. The
first couple of nights I was constantly puting my ear next to the base
just to make sure it was running, because I couldn't hear it tracking
with my eye at the eyepiece. Go figure. Also, in go-to's over a short
distance, like maybe 5 degrees, the scope moves so smoothly and quietly
unless you are looking in the finder-scope you can not tell that it has
moved just by watching the scope. But, all at the cost of more bulk and
weight, the 105 is considerably heavier than I expected and is on the
borderline of what I consider portable. But for me, I'll take it.

So, 90 or 105? If you want ultra-portable, go for the 90. If you want a
SLIGHTLY bigger-better but more expensive and bulkier scope. The 105
will do the trick. Is it worth the extra money? I shout a resounding
yes. The point is, you can't go wrong either way. In fact in my 10 years
of buying and using scopes I have come to a conclusion that

I profess nearly daily. The ETX line of scopes IS the best value
available in the telescope market, by a wide margin.

                       Thanks and keep up the super work,

                                        Mark A. Morris

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