Celestron Nexstar or Advanced Series?

I'm about to purchase my first telescope. I've narrowed my search for a new
telescope down to two. Both from Celestron. The 9.25" Nexstar or the 9.25"
Advanced Series. Both have the Starlight XLT coatings. The Nexstar has GPS
but I have a GPS receiver that I can connect to a laptop, so GPS is not
needed. My question is: Is there a vast difference in quality between the
two telescopes? There is a $1000 difference in price so I don't want to
just buy cheap if I'm going to sacrifice quality. But if GPS is all I'm
paying for with the Nexstar then I don't need it anyway. Any advice and
information describing the pros and cons of both would be GREATLY
appreciated.

Thanks!
Tom

"Sox-n-Eagles Fan" wrote in message
...
I'm about to purchase my first telescope. I've narrowed my search for a
new telescope down to two. Both from Celestron. The 9.25" Nexstar or
the 9.25" Advanced Series. Both have the Starlight XLT coatings. The
Nexstar has GPS but I have a GPS receiver that I can connect to a
laptop, so GPS is not needed. My question is: Is there a vast
difference in quality between the two telescopes? There is a $1000
difference in price so I don't want to just buy cheap if I'm going to
sacrifice quality. But if GPS is all I'm paying for with the Nexstar
then I don't need it anyway. Any advice and information describing the
pros and cons of both would be GREATLY appreciated.

Thanks!
Tom
What do you want to do with the scope?.
The Nexstar, is on a fork mount. This means that if you want to image, you
will have to buy a wedge (or only take very short exposures). The drives
on the Nexstar, are both smoother, and quieter than those on the AS
scopes.
The AS, is using a 'clone' GEM, which is of reasonable quality, and on the
examples I have tried seems to work fairly well. However I'd say it is
much better suited to the lighter scopes. The C9.25, weighs basically as
much as the C11, and for both these models, I'd say that the mount is
uncomfortably loaded.
The GPS, basically does almost nothing in a scope (assuming you are
working from a known location)!. However two other systems come as part of
the GPS installation, a compass, and a level. This allows the scope to
pretty nearly 'self align'. Provided you have accurate time (this is the
most important input from the 'GPS'), set the scope level, and aim it
accurately north, you can setup with either model in about the same time,
and I'd expect to be closer to aligned (using a polar scope), with the AS,
than the GPS manages with it's sensors.
You talk about a laptop, and this perhaps suggests you are considering
imaging?. If so, then the 'best' choice of the two, would be to get the
heavier CGE tripod (available as an option on the Nexstar), a good wedge,
and the Nexstar. However an even better option, would be to consider
buying the OTA alone, and getting a higher quality GEM (or of course, buy
the CGE). Unfortunately, with this, the price shoots up again...
Both scopes are optically the same, and for visual use, both will work
fine. The Nexstar will be slghtly quicker to setup, but you are only
talking a few seconds.

Best Wishes

"Roger Hamlett" wrote in message
...

The AS, is using a 'clone' GEM, which is of reasonable quality, and on the
examples I have tried seems to work fairly well. However I'd say it is
much better suited to the lighter scopes. The C9.25, weighs basically as
much as the C11, and for both these models, I'd say that the mount is
uncomfortably loaded.

According to the astronomics website, the 9.25 weighs in at 20 lbs., while
the C11 is 27 lbs.

Does a short-tube scope weighing 20 lbs. really tax that mount?

(I'm not really being argumentative, I am really interested in this mount
(and also the 9.25 scope). But if the mount can't even handle 20 pounds,
then I am better off with what I got.)

-Banjo

Banjo wrote:
"Roger Hamlett" wrote in message
...


The AS, is using a 'clone' GEM, which is of reasonable quality, and on the
examples I have tried seems to work fairly well. However I'd say it is
much better suited to the lighter scopes. The C9.25, weighs basically as
much as the C11, and for both these models, I'd say that the mount is
uncomfortably loaded.


According to the astronomics website, the 9.25 weighs in at 20 lbs., while
the C11 is 27 lbs.

Does a short-tube scope weighing 20 lbs. really tax that mount?

(I'm not really being argumentative, I am really interested in this mount
(and also the 9.25 scope). But if the mount can't even handle 20 pounds,
then I am better off with what I got.)

-Banjo


The CG5 is a clone of the Vixen GP, which is rated (by Vixen) for around
15 lbs. For long exposure imaging, cut that in half.

It's also worth noting that Vixen no longer offers the 8 lbs. 102ED F9
refractor on the GP, nor do they the R200SS (8" F4 Newt), but instead
have moved these scopes up to the GP-DX, which is rated for 22 lbs.

Beefing up the tripod helps considerably. The 2" steel leg tripod makes
the larger Celestron scopes possible on the CG5 for both visual use, and
for very short exposure imaging (planets and moon). I have a Konus 8" F5
Newtonian (15 lbs. x 36" long) on a Vixen GP using the AS 2" steel leg
tripod, and it exhibits vibrations when focusing by hand, as does the
102ED F9 refractor (8 lbs x 39" long), which came with the GP as a
package at the time. However, the vibrations settle very quickly and are
not a problem when observing. An electric focuser would resolve the
issue in both cases completely, and a buttery smooth, or dual speed
focuser would reduce the nusance factor probably in half.

That said both of these OTAs would be more solid on the GP-DX with the
2" steel leg tripod.

There's a lot of wishful thinking in this hobby, and lots of folks are
happy enough to be able to get a "visual" GEM that can handle a sub-20
lbs. 4" to 8" aperture scope for not a lot of money. I'm one of them,
and the CG5 is a decent clone of the twice as expensive GP, making it
capable of the same tasks visually.

But for imaging anything other than planets, your results will be more
closely tied to the mount, than they will any other piece of equipment
involved. It's not ridiculous to have a $3000 mount rated for 60 lbs.
(CGE, Losmandy G11), and a $500, 13 lbs. x 13" long C8 telescope with a
sub-$1000 CCD (SAC class) camera for imaging.

If you want a 9.25 to be rock solid, then the CGE is the way to go as a
package deal, or the G11 purchased separately. If you want a stable
C9.25 for visual, and for imaging planets and moon, get the GP-DX and a
solid tripod or pier. If you want GoTo with this package, get a GP-DX
without tripod, and the CG-5GT used on Astromart for $550. Transfer the
drives, electronics, and 2" steel leg tripod over to the GP-DX. Then put
the CG5 head back up on Astromart for $150.

Based on my experience with the 102ED F9 refractor, and the 8" F5 Newt
on the GP with AS tripod, I wouldn't go larger than the 15 lbs. C8N for
visual, or the C8S for imaging with the CG-5GT.

YMMV, so check one out before buying.

"Banjo" wrote in message
om...

"Roger Hamlett" wrote in message
...

The AS, is using a 'clone' GEM, which is of reasonable quality, and on
the examples I have tried seems to work fairly well. However I'd say it
is much better suited to the lighter scopes. The C9.25, weighs
basically as much as the C11, and for both these models, I'd say that
the mount is uncomfortably loaded.

According to the astronomics website, the 9.25 weighs in at 20 lbs.,
while the C11 is 27 lbs.

Does a short-tube scope weighing 20 lbs. really tax that mount?
Yes.
Remember that though this is a 'short tube' scope, it has a long focal
length. I'd say that the mount is 'adequate' for a 20lb scope, at low
magnification (though it is a direct clone of the GP, it does have much
better RA bearings than the original), but for imaging, or operating at
high magnifications, something better is needed. Once you add the dew
shield, and finder, and dovetail the C9.5, is basically 80% the weight of
the C11, and this is not that different. The figure you are quoting, is
the bare OTA.
If this was a scope with only a 1m focal length, it would be more
acceptable.

(I'm not really being argumentative, I am really interested in this
mount (and also the 9.25 scope). But if the mount can't even handle 20
pounds, then I am better off with what I got.)
There is a big question over what is meant by 'handle'. The normal rule of
thumb, is to halve the 'rated' loading for imaging. Some mounts manage
better than this (for instance the Losmandy G11, has a rating of about
60lb, yet many people image quite well, close to 50lbs), but you also have
to remember that a scope, is often loaded with other things. If you add a
heavy diagonal, and 2" eyepiece, dew shield etc., you can easily be adding
another seven or eight pounds to the load.
I consider the C9.25, 'borderline' for the mount, and definately only good
enough for visual use, with the C11, definately overweight.

Best Wishes

Thanks Stephen and Roger!

I don't do any imaging. I currently have a 10" dob and a 6" Orion on an old
Meade DS mount. I think I'll stick with those.

See ya!

-Banjo

"Sox-n-Eagles Fan" wrote in message
...
I'm about to purchase my first telescope. I've narrowed my search for a
new telescope down to two. Both from Celestron. The 9.25" Nexstar or the
9.25" Advanced Series. Both have the Starlight XLT coatings. The Nexstar
has GPS but I have a GPS receiver that I can connect to a laptop, so GPS
is not needed. My question is: Is there a vast difference in quality
between the two telescopes? There is a $1000 difference in price so I
don't want to just buy cheap if I'm going to sacrifice quality. But if
GPS is all I'm paying for with the Nexstar then I don't need it anyway.
Any advice and information describing the pros and cons of both would be
GREATLY appreciated.

Thanks!
Tom


Now thers's more choice

"dylan" wrote in message
...

"Sox-n-Eagles Fan" wrote in message
...
I'm about to purchase my first telescope. I've narrowed my search for a
new telescope down to two. Both from Celestron. The 9.25" Nexstar or
the 9.25" Advanced Series. Both have the Starlight XLT coatings. The
Nexstar has GPS but I have a GPS receiver that I can connect to a laptop,
so GPS is not needed. My question is: Is there a vast difference in
quality between the two telescopes? There is a $1000 difference in price
so I don't want to just buy cheap if I'm going to sacrifice quality. But
if GPS is all I'm paying for with the Nexstar then I don't need it
anyway. Any advice and information describing the pros and cons of both
would be GREATLY appreciated.

Thanks!
Tom


Now thers's more choice



As a Celestron user I would say don't buy Celestron.. Their ASGT mount is a
pile of pants and Customer service is very poor, but that's based on my
experience only.
Steve

"Steve - www.ukspeedtraps.co.uk" wrote in message
...
"dylan" wrote in message
...

"Sox-n-Eagles Fan" wrote in message
...
I'm about to purchase my first telescope. I've narrowed my search for
a new telescope down to two. Both from Celestron. The 9.25" Nexstar
or the 9.25" Advanced Series. Both have the Starlight XLT coatings.
The Nexstar has GPS but I have a GPS receiver that I can connect to a
laptop, so GPS is not needed. My question is: Is there a vast
difference in quality between the two telescopes? There is a $1000
difference in price so I don't want to just buy cheap if I'm going to
sacrifice quality. But if GPS is all I'm paying for with the Nexstar
then I don't need it anyway. Any advice and information describing the
pros and cons of both would be GREATLY appreciated.

Thanks!
Tom


Now thers's more choice



As a Celestron user I would say don't buy Celestron.. Their ASGT mount
is a pile of pants and Customer service is very poor, but that's based
on my experience only.
Steve
May I ask what was wrong with your ASGT?.
Did you deal with your distributor first (even in the US, it is the
distributor who should fix problems that arise when the mount is initially
delivered)?.
I have used the LX200 'classic', the LX200GPS, the Celestron ASGT, the
Vixen Skysensor 2000, the Vixen Sphinx, the Losmandy G11, the older
Celestron G5, the Meade LX90, the AP900, The LXD55, the LXD75, ETX-90, and
ETX-125, and found the ASGT, perfectly OK. With a little tweaking, it can
actually be pretty excellent for the money. It is certainly better than
the LXD55, and pretty comparable with the LXD75 (supports heavier loads
slightly better). It needs to have the mount zero point calibrated after
the first setup (initially, mine pointed about ten degrees right of the
target), but once this is done puts the target pretty much 'spot on',
within the limits of how accurately you align the marker arrows, and the
pole star. Though I think Celestron are trying to put too much weight on
the mount with their larger scopes, otherwise it performs pretty well.

Best Wishes

As a Celestron user I would say don't buy Celestron.. Their ASGT mount is
a pile of pants and Customer service is very poor, but that's based on my
experience only.
Steve
May I ask what was wrong with your ASGT?.
Did you deal with your distributor first (even in the US, it is the
distributor who should fix problems that arise when the mount is initially
delivered)?.

Best Wishes


As I said this decision is based on my experience.
Some problems are...

The software that is in the handset and on the motor controllers cause
runaway slews and other odd problems. (I have now updated the motor firmware
and that has improved it a bit)
The cable connectors on the leads have often failed me because of poor
crimps. Sometimes I can set it all up and I then get stuttering of the
motors. Sometimes removing the cables and starting over will cure it and
sometimes it won't cure it straight away without pushing down on the crimps
with a fine screwdriver.

I have had it repaired once already. I was not impressed with the way I was
dealt with. (main dealer) Celestron don't answer any emails, nor does the
main dealer. No point giving out an email address if you don't answer it,
maybe they are just being selective.

The power connector is a very poor fitting and the solution is to use a
screwdriver to open up the pin so its a better fit. (main dealer suggestion)
My solution was to replace both the connector on the mount and make a new
cable with a proper fitting connector. . Supplied power cable is to long and
you get a volts drop under load. If you have a ASGT mount make your own good
0.75 dia power cable and keep it below 2m. Use a good 5 amp power supply, I
know it can be powered by less but I notice slew and tracking problems if
the power supply is no good.

Quite a few of these problems and more have been reported on the Yahoo
Celestron user group.

On the other hand, now that I have given up on any support for the product,
and I am really not expecting the service to suddenly get any better. I have
decided I have nothing to loose by improving the mount myself. I will
investing in a new mount later this year anyway. (still undecided what
though)

I have stripped it down, polished the inner touching surfaces, re-greased
it, taken out any play with shims etc. mounted it on a pier. Updated the
software on the motors and generally fine tuned what I can. It is now not
that bad.
I am in the process of removing all the electronics mounted on the mount and
also the plastic housings and placing the electronics in a new remote
plastic box. I will be soldering all the internal connections (there are a
stack of them to go wrong) to remove any joint problems and adding new
cables and connectors to the two motors and hand controller. I will also
include the celestron programming box in my new box, a better power
connector and some other options that should have been included in the first
place.

By removing the plastic housings the mount runs so much quieter, noticeably
quieter I have to say.

I have made a new stainless counter balance arm that is 200mm longer, this
allows for better balancing of the 8"sct and the ED80 with the Canon 10d.
This also saves adding any more weight to balance the setup.

Just by working on the mount I now get better performance, it feels so much
smoother. The electronics once moved will cure the other problems. I believe
it is a better unit for the improvements.... Maybe I am just being a little
to picky, either way some of the problems other users and I have experienced
should not even exist. Its poor design in my eyes.

Rant over....
Steve