Re: Does the ETX 70 AT share the same mount as the ETX 90?

From: XxXxXxX (xxxx_at_xxxx.com)
Date: 07/12/04 

Date: Mon, 12 Jul 2004 10:20:37 -0400

Thanks for the detailed feedback...

I already have a 90mm MAK (Chinese variety, almost identical to the Konus
Motormax 90) on an EQ1 mount. My planetary and moon experience with this
has been great (although most of the planets have now set in the early
evening), I've been able to get Venus, Mars, Jupiter and Saturn in my scope
earlier this year with no problems.

The guide scope for the Mak is aweful, so I replaced it with a red dot sight
but I have been having problems with wide field items such as m31 (face it
I'm still having issues finding things in general). Polaris is easy to
start with... but for some reason I just can't seem to find anything. I've
got an Atlas of the Stars, Planetarium on my PDA, Starry Night on my Mac and
the Plannisphere Deluxe.

I've decided to purchase a used ETX-60 (about $200) and hopefully with it
and all this other stuff I can learn the night sky a little better and get a
better view of some Messier objects. My original question was essentialy if
I wanted to could I use an ETX70 mount and replace the OTA with my 90mm Mak.
I did find this site...

http://homepage.myeastern.com/~hfs/Projects/ETX70/ETX70.html

So it is possible, however the amount of machining involved makes me
hesitant.

I think I'm getting a good deal as the ETX-60 comes with the tripod (basic)
as well as a 40mm and 15mm Scopetronix Plossl eyepieces and some filters
(which would cost over $100 if I purchased them seperately).

At this point some wide feild objects will be more than interesting!

"Jon Isaacs" <jonisaacs@aol.com> wrote in message
news:20040712073157.04299.00001424@mb-m15.aol.com...
> >
> >Does the ETX 70 AT share the same mount as the ETX 90? My question being
if
> >I had an ETX 70 and wanted to upgrade the OTA can I do it?
> >
> >
> Hi:
>
> Historical point:
>
> There was an ETX-70 which shared the ETX-90 mount, it was dubbed the
ETX-70EC.
> The current ETX-70 has the cable attachments in the forks while the ETX-90
and
> the original ETX-70EC had the attachements in the base.
>
> However.....
>
> I do not recommend the ETX-70 because of its limited aperture and at least
in
> the one I had, not such great optics. As Rod said, the 70mm F5 scope does
best
> on widefield views, from the city it will not be impressive.
>
> My suggestions/thing:
>
> Take a look-see before you buy....
>
> Before you buy anything, I hope you take the time to find a way to see
these
> and other scopes in action under the night sky. Star parties, club
outings,
> friendly local amateurs, these can all give you a hand in getting a
feeling for
> what various telescopes and telescope designs can do.
>
> Many people are more than happy with the various EXT scopes and some are
not.
> They do have GOTO and the GOTO does work quite nicely. But there are many
> targets that are part of the AutoStar list that are very difficult or
> impossible to see even under dark skies, these are small scopes and of
long
> focal length (except the ETX-70) so what you see will be quite different
than
> what you might see in a larger scope/faster scope.
>
> My personal preferences do not lean towards GOTO, however in the interests
of
> giving it a try, I have owned an ETX-70, ETX-90 and ETX-125 and while each
had
> it merits, chosen to sell each. This is not to say that these are not
good
> scopes, rather they just not provide the sorts of views, especially of
Deep Sky
> Objects, that I enjoy. The long focal lengths and slow focal ratios of
the
> ETX-90 and 125 mean that the maximum the field of view is small and the
maximum
> exit pupil, (a measure of image brightness) is small.
>
> So, I hope that rather than jumping in and spending your money on one
these
> scopes you first take the time to find out what they can do, expecting to
see
> bright nebulas and extended galaxies and then seeing faint or non existent
> faint blobs can be disappointing.
>
> For those with a budget, the gambit is that one can either spend money on
> optics or on electronics but one trades optical prowess for Goto
capability.
> One can spend $700 and buy a scope that will point to many targets that
one
> cannot see or spend $700 on a scope that will show many targets but will
not
> point at them.
>
> These days, another options does exist and that this the Orion
Intelliscope
> DOBs, these do not have GOTO, they have PUSH TO, an intelligent controller
that
> allows you to choose what you want to see and then tells you which way to
move
> the scope to get there. The 8 incher will be around $700. There are also
> completely manual 8 inch DOBs available for $300.
>
> Also, I think the Celestron 130GT is an interesting option, full GOTO
under
> $400, it offers a fast 130mm Newtonian that provides decent widefield
views and
> high power ability. Something to consider anyway.
>
> ----
>
> So, my point is not to trash the ETX's.
>
> Rather my point is to suggest that it is best to be aware of their
limitations
> before you spend your hard earned cash, many people are happy with these
> scopes, but having realistic expectations and knowing what else is
available
> prior to your purchase is a good way to be happy with whatever you choose.
>
> Jon Isaacs
>

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