Is the ETX 90 AT a good first scope?

I've been reading a lot and was saving up for a good beginner scope, possibly
with a Go To feature. I live in a densely populated suburb outside Boston, so
I can do some viewing from my backyard, but will need to travel 30 minutes or
so to get to unobstructed, dark skies. I'm really interested in viewing the
planets and Moon. I recently got a copy of "Turn Left at Orion" and am
optimistic about being able to see some deep sky objects as well.

I was thinking that I'd buy one of the Meade DS-2130ATS scopes (5" f/8
Newtonian w/ go to mount). It sells for $400. It seems like it would be small
enough to move, yet still have enough aperture to see some things. But I just
saw that Meade's factory clearance store has some ETX90 AT models that
they've put on the DS go-to mounts for only $275 delivered.

Would this be a good starter scope for my purposes? I've always assumed
(maybe mistakenly) that the ETX scopes had better optics than the beginner
newtonians. Is it better to have the smaller scope with better optics than a
larger one with lower quality?

Any advice is appreciated.

Glen

Glen Ilacqua wrote:
I've been reading a lot and was saving up for a good beginner scope, possibly
with a Go To feature. I live in a densely populated suburb outside Boston, so
I can do some viewing from my backyard, but will need to travel 30 minutes or
so to get to unobstructed, dark skies. I'm really interested in viewing the
planets and Moon. I recently got a copy of "Turn Left at Orion" and am
optimistic about being able to see some deep sky objects as well.

I was thinking that I'd buy one of the Meade DS-2130ATS scopes (5" f/8
Newtonian w/ go to mount). It sells for $400. It seems like it would be small
enough to move, yet still have enough aperture to see some things. But I just
saw that Meade's factory clearance store has some ETX90 AT models that
they've put on the DS go-to mounts for only $275 delivered.

Would this be a good starter scope for my purposes? I've always assumed
(maybe mistakenly) that the ETX scopes had better optics than the beginner
newtonians. Is it better to have the smaller scope with better optics than a
larger one with lower quality?

Any advice is appreciated.

Glen





The ETX will have dew problems - the newtonian won't.

The newtonian will gather considerably more light.

The only advantages the ETX has are it's on sale, and it's more portable.

But I'll bet if you owned both, you'd find you liked the newtonian better.

They had the ETX-90 for $199 SHIPPED----It tracks but is not GOTO. I'm not
a fan of starting with GOTO. Better to actually POINT---you learn where
things are. Put that aside..... The ETX-90 is excellent and will get more
use than a Newtonian. A 6" Dob will be VERY uncomfortable. An 8" will be
heavy and useful only at night. The ETX-90 is great for "bird" watching
too.....good all around choice....

I looked at the one you mentioned----great deal.

Doink
"Glen Ilacqua" wrote in message
. ..
I've been reading a lot and was saving up for a good beginner scope,
possibly
with a Go To feature. I live in a densely populated suburb outside Boston,
so
I can do some viewing from my backyard, but will need to travel 30 minutes
or
so to get to unobstructed, dark skies. I'm really interested in viewing
the
planets and Moon. I recently got a copy of "Turn Left at Orion" and am
optimistic about being able to see some deep sky objects as well.

I was thinking that I'd buy one of the Meade DS-2130ATS scopes (5" f/8
Newtonian w/ go to mount). It sells for $400. It seems like it would be
small
enough to move, yet still have enough aperture to see some things. But I
just
saw that Meade's factory clearance store has some ETX90 AT models that
they've put on the DS go-to mounts for only $275 delivered.

Would this be a good starter scope for my purposes? I've always assumed
(maybe mistakenly) that the ETX scopes had better optics than the beginner
newtonians. Is it better to have the smaller scope with better optics than
a
larger one with lower quality?

Any advice is appreciated.

Glen

Doink wrote:
They had the ETX-90 for $199 SHIPPED----It tracks but is not GOTO. I'm not
a fan of starting with GOTO. Better to actually POINT---you learn where
things are. Put that aside..... The ETX-90 is excellent and will get more
use than a Newtonian. A 6" Dob will be VERY uncomfortable. An 8" will be
heavy and useful only at night. The ETX-90 is great for "bird" watching
too.....good all around choice....

Different strokes for different folks. As one example, I considered
the ETX-90 (the oldest one, the one that--as you say--doesn't GOTO)
before I eventually went with my C5+. It is cute and portable, and
is optically quite good, but even I, who have used a Toshiba Libretto
(a VHS-sized "laptop"), couldn't abide by its tiny controls. They
would have driven me to distraction. On the other hand, others clearly
have gotten quite a bit of good use out of it.

Out of my three main telescopes, the C5+ definitely gets the most
night-time use. (My Ranger is essentially just a home for the H-alpha
filter now.) But the 10-inch dob is a great scope and gets a decent
amount of use. I certainly do not find it cumbersome, and I am hardly
a strong fellow. It has gone to the LAAS dark sky site, some 90 minutes
from where I live, about as often as the C5+, for as long as I have had
both scopes.

One further reason that I am not whole hog about the ETX-90 (or the C5+
for that matter) as a first scope--my own experience notwithstanding--is
that its maximum field of view is a bit on the skimpy side. If you're
looking for portability in a first scope, you might consider one of the
ubiquitous 80 mm short-tube refractors. Not great at high power, but
still enough to do all right with Jupiter's belts, Saturn's rings, and
lots of stuff on the Moon. And it really shines with wide-field views
of open clusters. It's easy to set up and use, and doesn't cost an arm
and a leg.

--
Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

I agree completely Brian. I would have gone there----short tube
refractor---but it seems this NG gets all excited every time I do so....And
really, the question was whether this ETX-90 on sale is a good start....and,
yup, it is. I have an 8" reflector and a 13" Dob---my 5" Short tube sees
the most light---the 6" Intes Mak is next...then the etx-90 because I can
take it on the road---then the 80mm APO----everything else follows----and I
recently bought a 6" fast refractor....where does it end???????????
"Brian Tung" wrote in message
...
Doink wrote:
They had the ETX-90 for $199 SHIPPED----It tracks but is not GOTO. I'm
not
a fan of starting with GOTO. Better to actually POINT---you learn where
things are. Put that aside..... The ETX-90 is excellent and will get
more
use than a Newtonian. A 6" Dob will be VERY uncomfortable. An 8" will
be
heavy and useful only at night. The ETX-90 is great for "bird" watching
too.....good all around choice....

Different strokes for different folks. As one example, I considered
the ETX-90 (the oldest one, the one that--as you say--doesn't GOTO)
before I eventually went with my C5+. It is cute and portable, and
is optically quite good, but even I, who have used a Toshiba Libretto
(a VHS-sized "laptop"), couldn't abide by its tiny controls. They
would have driven me to distraction. On the other hand, others clearly
have gotten quite a bit of good use out of it.

Out of my three main telescopes, the C5+ definitely gets the most
night-time use. (My Ranger is essentially just a home for the H-alpha
filter now.) But the 10-inch dob is a great scope and gets a decent
amount of use. I certainly do not find it cumbersome, and I am hardly
a strong fellow. It has gone to the LAAS dark sky site, some 90 minutes
from where I live, about as often as the C5+, for as long as I have had
both scopes.

One further reason that I am not whole hog about the ETX-90 (or the C5+
for that matter) as a first scope--my own experience notwithstanding--is
that its maximum field of view is a bit on the skimpy side. If you're
looking for portability in a first scope, you might consider one of the
ubiquitous 80 mm short-tube refractors. Not great at high power, but
still enough to do all right with Jupiter's belts, Saturn's rings, and
lots of stuff on the Moon. And it really shines with wide-field views
of open clusters. It's easy to set up and use, and doesn't cost an arm
and a leg.

--
Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Would this be a good starter scope for my purposes? I've always assumed
(maybe mistakenly) that the ETX scopes had better optics than the
beginner
newtonians. Is it better to have the smaller scope with better optics
than a
larger one with lower quality?


Any advice is appreciated.


Glen
---------

Glen:

In the past few years I have owned an ETX-90, an ETX-70 as well as an
ETX-125 and an Orion XT-8 Dobsonian.

Some thoughts:

1. Please avoid the DS-2130ATS, this is what is known as a "short tube
Newtonian", is uses a fast spherical mirror and a "barlow/corrector" in
the focuser to achieve the necessary focal length. Short tube
newtonians invariably have poor optics. The mount is flimsy/shaky.
The university where I work bought some for their club but after I
pointed out some of their weaknesses they returned them. Also, the DS
mounts are not robust and apparently have problems with the gears....

2. With that $400 you can buy either that ETX-90 or an 8 inch DOB.
With the ETX you are buying a 1250mm focal length scope with a 1.25
inch focusr with GOTO, it is not the optics you are buying, it is the
electronics and gears.

With the 8 inch DOB, your are buying a 1200mm focal length scope with a
2 inch focuser and some good optics with enough aperture to "light" up
the night sky. It has 2.25x the possible resolution and gathers 5
times as much light as the ETX-90. This means that planets will be
brighter and sharper, DSOs will be far brighter and you will see lots
of stuff you cannot see with the ETX-90.

The mount will be solid, and with 2 inch eyepieces the field of view is
potentially much larger than the ETX. DOBs are comfortable because you
can sit alongside them and view for hours on end.

I look at it like this:

Yes, the ETX-90 has GOTO and a large data base of targets but most of
them will be invisable. The 8 inch DOB will show show you many more
targets and do things like resolve M-13 which is barely a smudge in an
ETX-90...

At this price point you either buy a scope that shows a lot but your
need to point it or you buy a scope that points at lots of stuff that
it cannot see...

And again, please avoid the DS-2130ATS, it's not a good choice.

jon

Glen Ilacqua wrote:
I've been reading a lot and was saving up for a good beginner scope, possibly
with a Go To feature. I live in a densely populated suburb outside Boston, so
I can do some viewing from my backyard, but will need to travel 30 minutes or
so to get to unobstructed, dark skies. I'm really interested in viewing the
planets and Moon. I recently got a copy of "Turn Left at Orion" and am
optimistic about being able to see some deep sky objects as well.

One thing to consider is that you don't need "Go To" for observing the
planets and the Moon. The most interesting planets are among the
brightest and easiest objects in the sky to find. So if you can put
that money into better, bigger optics, you'll have more fun.

I would suggest that it's rare to find a catadioptric telescope that can
match the optical quality of a good newtonian of the same size or price.
It's always better to have fewer surfaces and mirrors.

Mojo
--
Morris Jones
Monrovia, CA
http://www.whiteoaks.com
Old Town Astronomers: http://www.otastro.org

Thanks Jon-

The advice on the DS-2130 is very helpful, I'll steer clear. It's hard to
know just by reading the magazines... they seem to like everything that comes
from an advertiser. Your point about the GOTO system taking the little ETX to
thousands of invisible targets is also well taken. And I get it that a large
aperture scope will be much more interesting to look through. Unfortunately,
an 8" Dob is way too big for me. I don't have room to store it and it would
virtually fill up my compact sedan (rear seat doesn't fold down - damned
Ford). One of the things I like about a smaller scope is the idea that I can
take it with me when I go away... say to Vermont for the weekend, whether I
use it or not... I have the option. I can't see me taking even a smaller Dob
or tripod mounted newt on a whim.

When Hale-Bop came through I bought a really bad Tasco 114mm newtonian/EQ
for $50 from a neighbor. It was one of those department store scopes. But
even that scope at 4" was a handful to move around... mostly because of the
crappy wooden tripod that didn't like to break down. I'll have to move this
thing every time I use it, so I'm a little leery of getting something too
big. So I guess the question is this: At $275 delivered is the ETX a bad
choice for a smaller scope? Some have suggested a short tube 80mm refractor,
but that will gather less light still, and won't save me much money over the
special deal. The other thing about the ETX that seems good is that they are
popular and can be used for terrestrial viewing.

What I want to avoid is a scope that just sucks to use (like the Tasco). What
I've learned from your post as well as the others, is that I need to get to a
club and look at some people's scopes before buying.

Thanks VERY much for the advice.

Glen






On Tue, 27 Sep 2005 18:06:38 -0400, wrote
(in article .com):

Would this be a good starter scope for my purposes? I've always assumed
(maybe mistakenly) that the ETX scopes had better optics than the
beginner
newtonians. Is it better to have the smaller scope with better optics
than a
larger one with lower quality?


Any advice is appreciated.


Glen
---------

Glen:

In the past few years I have owned an ETX-90, an ETX-70 as well as an
ETX-125 and an Orion XT-8 Dobsonian.

Some thoughts:

1. Please avoid the DS-2130ATS, this is what is known as a "short tube
Newtonian", is uses a fast spherical mirror and a "barlow/corrector" in
the focuser to achieve the necessary focal length. Short tube
newtonians invariably have poor optics. The mount is flimsy/shaky.
The university where I work bought some for their club but after I
pointed out some of their weaknesses they returned them. Also, the DS
mounts are not robust and apparently have problems with the gears....

2. With that $400 you can buy either that ETX-90 or an 8 inch DOB.
With the ETX you are buying a 1250mm focal length scope with a 1.25
inch focusr with GOTO, it is not the optics you are buying, it is the
electronics and gears.

With the 8 inch DOB, your are buying a 1200mm focal length scope with a
2 inch focuser and some good optics with enough aperture to "light" up
the night sky. It has 2.25x the possible resolution and gathers 5
times as much light as the ETX-90. This means that planets will be
brighter and sharper, DSOs will be far brighter and you will see lots
of stuff you cannot see with the ETX-90.

The mount will be solid, and with 2 inch eyepieces the field of view is
potentially much larger than the ETX. DOBs are comfortable because you
can sit alongside them and view for hours on end.

I look at it like this:

Yes, the ETX-90 has GOTO and a large data base of targets but most of
them will be invisable. The 8 inch DOB will show show you many more
targets and do things like resolve M-13 which is barely a smudge in an
ETX-90...

At this price point you either buy a scope that shows a lot but your
need to point it or you buy a scope that points at lots of stuff that
it cannot see...

And again, please avoid the DS-2130ATS, it's not a good choice.

jon

Thanks Brian-

All good info to consider. I'll have a look at the 80mm shorties. Someone
else suggested that I don't need the GOTO stuff to look at the planets and
moon. I may pass on the electronics. In any event, I have to get out to a
viewing and look at some other people's gear before I buy anything. Thanks
much for the advice.

Glen


On Tue, 27 Sep 2005 16:43:36 -0400, Brian Tung wrote
(in article ):

Doink wrote:
They had the ETX-90 for $199 SHIPPED----It tracks but is not GOTO. I'm not
a fan of starting with GOTO. Better to actually POINT---you learn where
things are. Put that aside..... The ETX-90 is excellent and will get more
use than a Newtonian. A 6" Dob will be VERY uncomfortable. An 8" will be
heavy and useful only at night. The ETX-90 is great for "bird" watching
too.....good all around choice....

Different strokes for different folks. As one example, I considered
the ETX-90 (the oldest one, the one that--as you say--doesn't GOTO)
before I eventually went with my C5+. It is cute and portable, and
is optically quite good, but even I, who have used a Toshiba Libretto
(a VHS-sized "laptop"), couldn't abide by its tiny controls. They
would have driven me to distraction. On the other hand, others clearly
have gotten quite a bit of good use out of it.

Out of my three main telescopes, the C5+ definitely gets the most
night-time use. (My Ranger is essentially just a home for the H-alpha
filter now.) But the 10-inch dob is a great scope and gets a decent
amount of use. I certainly do not find it cumbersome, and I am hardly
a strong fellow. It has gone to the LAAS dark sky site, some 90 minutes
from where I live, about as often as the C5+, for as long as I have had
both scopes.

One further reason that I am not whole hog about the ETX-90 (or the C5+
for that matter) as a first scope--my own experience notwithstanding--is
that its maximum field of view is a bit on the skimpy side. If you're
looking for portability in a first scope, you might consider one of the
ubiquitous 80 mm short-tube refractors. Not great at high power, but
still enough to do all right with Jupiter's belts, Saturn's rings, and
lots of stuff on the Moon. And it really shines with wide-field views
of open clusters. It's easy to set up and use, and doesn't cost an arm
and a leg.

Your thinking is in line with what I was thinking. And I figure that if I
don't get into astronomy it will be easy to sell, and I may just keep it to
look at things on the ground. If you've followed the thread, most people
don't like this scope for a number of reasons - but it just might be the
right mix for me.

In any event, I'm going to get to a viewing and look at some other people's
gear before taking the plunge.

Thanks much for the advice.

Glen



On Tue, 27 Sep 2005 16:17:16 -0400, Doink wrote
(in article ):

They had the ETX-90 for $199 SHIPPED----It tracks but is not GOTO. I'm not
a fan of starting with GOTO. Better to actually POINT---you learn where
things are. Put that aside..... The ETX-90 is excellent and will get more
use than a Newtonian. A 6" Dob will be VERY uncomfortable. An 8" will be
heavy and useful only at night. The ETX-90 is great for "bird" watching
too.....good all around choice....

I looked at the one you mentioned----great deal.

Doink
"Glen Ilacqua" wrote in message
. ..
I've been reading a lot and was saving up for a good beginner scope,
possibly
with a Go To feature. I live in a densely populated suburb outside Boston,
so
I can do some viewing from my backyard, but will need to travel 30 minutes
or
so to get to unobstructed, dark skies. I'm really interested in viewing
the
planets and Moon. I recently got a copy of "Turn Left at Orion" and am
optimistic about being able to see some deep sky objects as well.

I was thinking that I'd buy one of the Meade DS-2130ATS scopes (5" f/8
Newtonian w/ go to mount). It sells for $400. It seems like it would be
small
enough to move, yet still have enough aperture to see some things. But I
just
saw that Meade's factory clearance store has some ETX90 AT models that
they've put on the DS go-to mounts for only $275 delivered.

Would this be a good starter scope for my purposes? I've always assumed
(maybe mistakenly) that the ETX scopes had better optics than the beginner
newtonians. Is it better to have the smaller scope with better optics than
a
larger one with lower quality?

Any advice is appreciated.

Glen