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ETX-125EC USER FEEDBACK - JUNE 1999
Last updated: 30 June 1999

This page is for user comments and information specific to the Meade ETX-125EC. Accessories and Feedback items appropriate to the original ETX model, ETX-90EC, and the ETX-125EC are posted on other pages as appropriate. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me and I'll post them. Please use an appropriate Subject Line on your message. Thanks.


Subject:	 Image brightness and f/stop
Sent:	Wednesday, June 30, 1999 15:08:59
From:	chu@nceye.net (H. Willy Chu)
I am just getting into astronomy, so please excuse this basic question. 
I have ordered a nice pair of binoculars and the Stary Nights CD for my
Mac to begin learning my way around.  In the meanwhile I am researching
what size telescope to eventually buy, which is how I found your very
informative website.

My familiarity with optics is from 35mm photography.  I was confused by
the discussion comparing the 90mm vs 125mm ETX.  I quote, "To sum
up...an f15 scope and an f6.3 scope used at 50X will be equal in image
brightness!"  How can this be so?  I would say that these two scopes
differed by more than two f/stops (I am not sure if you speak in terms
of f/stops in astronomy), or four times the amount of transmitted light.
In photography a lens with a lower numerical f/stop is "faster," that
is, it can be used in lower light conditions or with a faster shutter
speed.

Thinking this through, I would say that since the area of a circle 125mm
in diameter is almost exactly twice that of a 90mm circle, then twice
the number of photons are entering the larger scope.  If twice as
photons are focused into an image of the exact same size, then the image
must be twice as bright-or one f/stop difference.  So that if you are
taking a picture of this image, you would need only half the exposure
time.

I was looking at John Deriso's excellent comparison table.  It shows
that at 48x the ETX-125 has a relative brightness of 1.93 compared to
the ETX-90, in other words, twice the brightness.  For astrophotography
I would think that you would need only half the exposure time, 30
minutes instead of 60 minutes, for example.  Or that an object 1.4 times
farther away (since light falls off as the square of the distance) would
appear just as bright with a larger telescope.  I realize that our eyes
are not the same as film-twice as much light intensity does not
translate to a doubling of the perceived brightness in our brain. 
Perhaps this is the source of the confusion?

I would appreciate it if you could shed some light, no pun intended, on
this subject!

Thanks.
--
Willy
chu@nceye.net
Mike here: As you know, the formula for f-stop is focal length divided by aperture. In photography, you are usually keeping the lens focal length constant as you change the f-stop on a given lens. This means you are changing the effective aperture for that lens. With telescopes, the same formula applies but normally different telescopes are used, with different apertures and focal lengths. A larger aperture telescope can be slower than a small aperture telescope, as is the case with the ETX-125EC versus the ETX-90EC. So even though you have more light gathering power, you can lose this gain from the slower system.

Subject:	 RE the 125
Sent:	Tuesday, June 29, 1999 19:06:37
From:	rkennedy@loquitur.com (Roderick Kennedy)
I got a Celestron G-5 last winter and had a ball with it.  I wanted
something just a bit bigger than the 3.5" for some reason, and was out
two and three times a week in the mild winter we had here in NM

The Andromeda Galaxy looked like a bigger ball of cotton when I found
it, but the equatorial bands on Jupiter were quite apparent, and saturn
was a lot of fun, too.  That double cluster over by Cassiopeia was a bit
too wide for my 25mm eyepiece, but looked like a star wars backdrop
anyway.  I think a 5" scope is a good thing for persons who want a
little more light gathering and still have portability in mind.

I paid just a little less for the G-5 than the ETX-125, and have a cheap
equatorial mount tripod that came with it.  I like the 'scope an awful
lot, but think the ETX-125 is likely to be a better deal.

--
Roderick Kennedy
P.O. Box 133, Albq. NM 87103
505.841-8287 / FAX 505.841-8228
"For business reasons, I must preserve the outward sign of sanity."
- Mark Twain, letter to William Stead, 1890

Subject:	 RE: ETX 125 and Tripod choice
Sent:	Monday, June 28, 1999 20:44:56
From:	mikev@virtechsolutions.com (Michael Virsinger)
Thanks for the great site, Mike. I know how much effort goes into
maintaining quality information. In regard to J Roloff 's comments
regarding the stability of Meade's ETX Field Tripod with the 125, I too
share his concerns. As an alternative, I am strongly considering using a
Meade LX50 tripod ($295) and the LXTRAD - LX Series ETX Tripod Adapter
($24.95) from ScopeTronix resulting in what should be an extremely
sturdy Alt/Az (albeit expensive) mount.

Regards,

Michael Virsinger
mikev@virtechsolutions.com

Subject:	 First 'scope
Sent:	Monday, June 28, 1999 18:08:10
From:	petevas@breathemail.net (Peter Vasey)
At last! - someone has actually seen a 125! (Thanks to Robert Bagley)
And it sounds very nice too.  I'm in the market for a Cassegrain type
fork mounted 'scope (fed up with fighting the shaky equatorial mount and
cumbersome tube on a trial 8" Newtonian), but can't decide whether to go
for the larger aperture but reduced portability of an 8" LX10, or hold
out for the125 (with its better optics and the temptation of the
Autostar) which isn't expected to arrive here in England until September
or later  (if then!).  Reading John Latini's letter put me off briefly,
but surely the figures he is quoting are for increased magnification,
using the same eyepiece.  With the 90 and 125 both at 48x, the 125 has
the same field of view and almost twice the brightness.  But I am
particularly interested in deep sky - will the increased aperture (still
less than half the area of an 8") be enough for adequate deep sky
viewing, albeit superb for moon and planets??  How about the changed
finder? - I generally line up with both eyes open when star hopping, but
the right angled finder (presumably fitted because of the problems with
the 90 when near the zenith) puts paid to that.  Any input to help my
decision very welcome.  Or perhaps I'll just have to wait until the
beastie crosses the pond!

Peter Vasey
Mike here: On the finder question, you can add one of the various 1x or red-dot finders from Rigel Systems, Scopetronix, or Telrad. That will let you use both eyes very conveniently. As to deep sky, larger aperture is better. But we'll have to wait for real user reports to know how well the ETX-125EC works.

Added later:

Thanks, Mike for your reply.  Just a few thoughts on the deep sky
position.  Of course 'size matters', but the ultimate performance of a
telescope is limited by the wavelength of light.  The universally used
Dawes Limit of resolution is given by the formula 4.56/aperture (in
inches).  So the resolution limit for a 90 mm aperture is 1.3
arc-seconds, just enough to easily resolve the Epsilon Lyrae Double
double, and for a 125 is 0.91 arc-seconds.  Consequently, with light
gathering proportional to the square of the aperture, and assuming
comparable optical quality, the 125 will detect objects twice as faint
as those detectable by the 90 under similar conditions, with resolution
(important for globular clusters, galactic structure and planetary
detail) improved by 44%.  For an 8" (200 mm) 'scope the light gathering
is five times greater than a 90 (two and a half times greater than a
125), and the Dawes limit is 0.57 arc-seconds.  Larger 'scopes are
obviously able to detect much fainter objects, but their resolution
becomes limited more and more by the atmospheric conditions.  So I
suspect that given clear dark skies the 125 will serve quite well for
deep sky objects.  Although they will be fainter than with larger
instruments, the high quality and extra contrast of the Matsukov optics,
comparable to quality refractors of the same aperture costing twice as
much or more, will help to compensate.  Which is where the ETX
portability pays off - if the dark skies won't come to your light
polluted backyard............

Perhaps I've talked myself into waiting - after all, I live near
Sunderland, England, the home of Pyrex glass!  Hope there are some
'hands on' reports soon.

Subject:	 ETX 125 and Tripod choice
Sent:	Sunday, June 27, 1999 19:02:02
From:	jroloff@earthlink.net (James Roloff)
I hope I'm on an "early" list for the 125, but refrained from choosing
the "field tripod" after reviewing comments here and elsewhere. While I
know no one has actually seen in "real" conditions much less tried one
of these, I would appreciate the conjectures of the cognoscenti here as
to likely "good alternative tripod choices" for this "big brother" of
the 90. Thanks in advance.

J Roloff
jroloff@earthlink.net

Subject:	 Rationale for going to an ETX-125
Sent:	Saturday, June 26, 1999 11:15:03
From:	johnlat@earthlink.net (John R Latini)
Just  reflecting recently while I am waiting for the 125s to roll out,
probably like a lot of others who are waiting for their order. All
things considered:, I have been thinking why I want the 125 instead of
the 90 ETX in the first place.

Considering the ETX-90 is the best selling telescope in the world, and
knowing the reasons are, very small portable size, Autostar & goto,
sharp Mak optics, I'm analyzing why I am getting the 125 at all. My
original thought (like many others) is that "HEY 5" apeture means 100%
increase in light gathering, and with the goto and autostar, I'm getting
closer to an 8" LX-200  for 1/3 the price, and still have table top
portablty", although not as nice as the 90, all for only $300 more;  (I
know the LX-200 is PRO-Quality, but still, there is some comparison
there).

According to John Derisos chart, there is only an effective increase of
27% improvement, so you are really not getting "that much more" as I had
originally thought with the f/15 by 1900mm design, and you are loosing
the "extreme portability" and hand held ergonomics of the 90 to a 19 lb
125-ETX.  And the smaller field of view of the 125 compared to the 90.

The thought has crossed my mind about getting the 90, and using the
extra $300 towards a 12" Dob.

I'm not saying I want to get a 90, I'm just bringing up the subject to
toss around and discuss. What do you think?  Where do you see any 
significant advantage to getting the 125 over the 90?

Thanks
John  L.
Mike here: For me, I think I'll stick with the -90 for now. Someday I'd like a 10 or 12" LX200.

Subject:	 ETX-125
Sent:	Saturday, June 26, 1999 0:09:29
From:	exorcist@ix.netcom.com (Robert Bagley)
I've been enjoying your page off and on for a while now. I've got some
info on the 125.  Last weekend I was at Oceanside Photo & Telescope,
they had the Meade rep there and an ETX-125 on display.  We didn't get
to take it out to test it because of the overcast weather we've had here
in SOCAL this year but I did play with it in the store.  The ETX 90EC
right next to it sounds like it's trying to grind wheat when it moves
and it looks slightly jerky while it's slewing but the 125 makes almost
no noise at all and is as smooth as butter!  The 125 definitely has a
superior drive motor/gearing over the 90!  Also if asthetics matters the
125 looks well ballanced compaired to the 90's overlarge looking base. 
I think the 125 will be more on-par with the LX series scopes as far as
imaging and tracking are concerned but we'll all find out for sure in the
next month or so.  I know I'm looking forward to getting my 125 as soon
as they are out.  Hope this helps to clear up some questions for folks.

                                                        Rob.

Subject:	 ETX 125 newbie with CCD question
Sent:	Saturday, June 26, 1999 0:06:04
From:	mwaltz@execpc.com (Mark Waltz)
I'm in the ETX125 queue, and was rummaging around the web and found your
great site.

I did a lot of astrophotography on my high school's Celestron 8 SCT back
when the scope was orange and the film was black and white. The ETX is
going to be -my- first scope.  I was wondering about CCD work through
the ETX.  I know the ETX isn't particularly good at long-term tracking
(so film is out).  But CCDs can stack short-exposure shots.  My question
is, can I use a Pictor 216XT or something on the ETX?  Can the Pictor
(or whatever) take advantage of the ETX drive system for autoguiding? 
Yea, I know, it takes the romance out to autoguide, but I've earned my
stripes freezing my butt off in Wisconsin's below-0 nights staring at a
guide star until I hallucinate.  I prefer results over war stories these
days.

Maybe I should be looking at a different scope, but the portability,
cost-effectiveness and features-galore on this little beauty have hooked
me (not to mention the price.  There's enough left over for me to at
least -consider- a CCD camera!)  Besides, I fully expect to be spending
more time viewing with friends and my kids than shooting, which, if I
recall, was a rather lonely experience.

Thanks for the advice, and for the site -- I've bookmarked it.

Regards,
Mark Waltz
Mike here: Search the site for "CCD"; you'll find lots of references to using CCDs with the ETX. I don't know about autoguiding but since the Autostar has most of the LX200 commands, I would suspect it could be done. How accurate the corrections would be remain a question however.

Subject:	 PRICING FOR MODEL: ETX 125 EC
Sent:	Thursday, June 24, 1999 13:23:49
From:	herb.windrich.b@bayer.com (Herb Windrich)
My son is interested in buying above mentioned model when it comes out
in July/August. We have called dealers, went to shows, checked in retail
stores, on line stores, magazines, science centers etc to get a better
feel for the price of this telescope. Surprisingly the answer  was
always $895 or 899.

My questions: Are these telescops price protected by Meade? Are we to
bargain with the seller? Is $895 a realistic price or is it meant to be
a MSRP?

We are newcomers to buying astrology related products and would
appreciate it to hear your opinion on this pricing matter.

With best regards, Herb Windrich
Mike here: First off, you are buying "astronomy" related products not "astrology" (unless you plan on doing your own horoscopes). And the current "suggested retail price" is $895. Some dealers may charge more if they add some value to your purchase (like a thorough testing). You probably won't find many dealers charging less since it is already a popular item.

Subject:	ETX 125 Availability
Sent:	Wednesday, June 23, 1999 18:26:29
From:	JDukeUAL@aol.com
I spoke to one of the reps at Astronomics today trying to find out when
the 125's would ship.  His latest info from Meade is that the first
group of 60 or so should go out in about a week (wishful thinking?).  I
ordered one in early May, so it looks like I may get mine (I'm about 175
on the shipping list) when the second batch to Astronomics goes out. 
When I actually get my hands on one, I'll drop a note to give my
impressions of the scope.

Subject:	 Re: E Mosser's question on ETX125
Sent:	Wednesday, June 23, 1999 17:54:36
From:	jh@brainiac.com (Joe Hartley)
emosser@gte.net (E Mosser) asked:
> Technically...will the high focal ratio for the etx125 also restrict the
> viewing of the faint fuzzies.

The short answer is no.  Having a high focal ratio (focal
length/aperture) doesn't affect viewing in the same way it affects
photography.  When I asked a similar question on the etx@listbot.com
mailing list, Rod Mollise gave a very cogent explaination:

> An f5 and an f10 telescope will 
> produce an image of equal brightness _when used at the same magnification_. 
> Now, a longer focal length eyepiece will be needed on the long focal length 
> eyepiece, but the images will be equally bright. Actually, the image in the 
> LONGER focal length scope may actually be BRIGHTER, since telescopes (non 
> refractors, of course) with shorter focal lengths generally also have 
> _larger_ secondary mirrors (though the difference probably wouldn't be 
> detectable by eye). To sum up...an f15 scope and an f6.3 scope used at 50X 
> will be equal in image brightness!

The difference here is the focal length of the eyepiece needed to get
the same magnification.  The ETX90, with its 1250mm focal length,
achieves 50x with a 25mm eyepiece, while the ETX125, with its 1900mm
focal length, gets 50x with a 38mm eyepiece.  There's also the fact that
the 125 has a larger aperture, so with the same eyepiece, the views are
inherently brighter in the 125.  John Deriso posted a nice chart
comparing the 2 ETX models in terms of magnification, field of view, and
brightness.  It's on Mike Weasner's Mighty ETX site in the June
ETX-125EC feedback area (it was dated June 8.)

Hope this helps!

======================================================================
        Joe Hartley - jh@brainiac.com - brainiac services, inc
     12 Emma G Lane, Narragansett, RI : 02827 - vox 401.782.9042
Without deviation from the norm, "progress" is not possible. - FZappa

Subject:	 an update
Sent:	Tuesday, June 22, 1999 20:20:03
From:	beksten@home.com (Brick Eksten)
Spoke again to the dealer today, they assured me the scope would go out
of meade at the end of the month, delivery on or around the 10th - 15th
of July.  Woohoo.  Can't wait.

Subject:	 ETX125
Sent:	Monday, June 21, 1999 13:24:06
From:	Paul.Checkovich@lmco.com (Paul Checkovich)
I haven't owned a 'scope since '65, but my kids want to buy me one
(combination birthday/Fathers day present) since i just moved to the top
of a smallish mt. in the NE US, and the seeing is pretty good with
10x50s. I called Meade and they say the 125 will be out the end of June.
While I don't know what the price will be (my kids are young
professionals and can probably afford somewhat more than I could at
their ages) I am more worried about the 'new model' syndrome, a la
automobiles - should I wait for the ETX125 to go through a shake-down
period, or does Meade do that up front and not start selling the new
model until the problems are worked out?    gkrauss@stny.rr.com
Mike here: The price is $895 and I would hope that dealers should start receiving them any day now. As to the "bugs", since the design is essentially the same as the ETX-90EC only larger I would expect that there should be no "new model" concerns.

Subject:	 125mm Mak and Deep Sky
Sent:	Monday, June 21, 1999 10:08:39
From:	johnlat@earthlink.net (John R Latini)
I keep reading that a minimum of 6" and preferably 8" is needed to get
any satisfactory deep sky visual images. I also read that aside from
some fuzzy blobs, a 5" just won't cut it for deep sky. Besides that, the
1900mm X f/15 focal specs of theMaksutov, will not cut it for deep sky.
Someone who knows scopes in a camera shop told me that the Maksutov is
mainly for "Sharp" images of the planets, but NOT for deep sky, and he
recomended a larger aperture, stating that I would be dissapointed with
the 5" Mak.

Could you comment on this.

Thanks
John L.
Mike here: Satisfaction can be measured somewhat in the eye of the beholder. You may or may not be disappointed in the ETX-125EC versus a larger scope. Yes, Maks are good for presenting high contrast views of objects like the Moon and planets but that doesn't mean they are worthless for nebulae. Consider ALL the ways you want to use a telescope and compare that to your budget. Then buy accordingly.

Added later:

You say the 5" Mak is "not useless" for nebula. So you are saying that
there is SOME use for deep sky. What galaxies and nebula could one
access in a 5" Mak for deep space?
Mike here: Remember that extended faint objects are difficult in any size telescope. Only CCD imaging or long duration astrophotography can show the details as seen in photos. You can see many galaxies but usually only the central portion, not the arms. Many nebulae will appear as faint "blobs" of light. Larger telescopes will show these as brighter faint blobs of light.

And more:

So as far as deep sky objects, it sounds like you are saying there is
not much difference between a larger apeture scope for deep sky, except
that it makes the objects brighter, but not necessarily clearer. Also
once again, so since the "great images result from CCD", is it possible
to do CCD on the ETX on both planets and deep sky?  It's just a matter
of tracking and enough time exposure, right? Correct me if I'm wrong, it
is the f/15 and the 1900mm length, and the weak plastic construction
that would not make CCD on the ETX-125 possible? Or is it possible with
some "micky-mouse" inventions?
Mike here: CCD can be done with the ETX-90 models (search the site for "CCD" now that it is back up). But it requires a lot of patience and practice. I'm sure that the ETX-125EC can use a CCD with the same limitations.

Subject:	 Miami Valley Telescope Fair
Sent:	Friday, June 18, 1999 22:01:14
From:	macnoid@wcoil.com
Hi my name is Jim, and I dropped a note earlier this month about
attending the Miami valley Astronomical society's annual Telescope Fair
in Dayton Ohio..I'm sorry to say there wasn't a Etx 125 on display,just
Etx 90 computer controlled telescopes for sale..I asked some questions
about the Etx 125's ability to take deep space photos but was informed
that the focal length is to long and no one mentioned a focal reducer
for it..Hope to have better luck in the fall.I hope to attend The
Cincinnati Observatory Center's Scope Out 99! but by then I believe
everyone will have the information they need on the Etx 125!...

Thanks Jim

Subject:	 more on ETX ruggedness
Sent:	Thursday, June 17, 1999 16:24:37
From:	johnlat@earthlink.net (John R Latini)
The 125 has metal ball bearings  in RA axis according to the new Meade
catalogue. From what you know about OTHER telescopes, would this mean
that it could support more accessory weight, or does this have nothing
to do with supporting weight? Maybe Meade engineers have an answer, but
they can't be reached.

Thanks again
John L.
Mike here: It could help reduce flexing. But other than that, I don't think it would help.

Subject:	 ETX125ec
Sent:	Tuesday, June 15, 1999 22:27:13
From:	amurphy@idworld.net (Mike & Sandra Murphy)
Just got notice that the ETX125ec will not be shipping till late July or
early August. Has anyone else heard different ?

Mike M
Mike here: Lots of rumors/conjecture on dates.

Subject:	 Re: Re: ETX delivery
Sent:	Tuesday, June 15, 1999 16:17:08
From:	beksten@home.com (Brick Eksten)
I hope they were trying to cool my enthusiasm, in some sort of mad
reverse psychology move.  If so, it has backfired because the Argonaut
Mak-Newtonian is looking pretty good right now.

Subject:	 ETX delivery
Sent:	Monday, June 14, 1999 17:48:26
From:	beksten@home.com (Brick Eksten)
Ugh,  I heard from two dealers, both here in Toronto that Meade is now
say end of July/August for delivery.  Anyone heard any good news?
Mike here: If you are refering to the ETX-125EC, July has been a typical date cited.

Added later:

Well, I didn't want to rain on any parades, but the major dealer here is
quoting a possible september.  Time to go check out that argonaut.

Subject:	 Barlows with the ETX
Sent:	Wednesday, June 9, 1999 9:27:18
From:	johnlat@earthlink.net (John R Latini)
Do I ask enough questions or what? (lol). I hope other users get some
help from my questions also.

I talked to Al Nagler and he said you don't need a Barlow on a scope
like the 125.  This was after I told him how happy I was with his 2X
Barlow I used on another scope. He said, the Barlow just adds more
optics for the light to pass through, and thus, takes away from a
brighter and clearer image. I think he was only refering to the ETX-125,
in this case. I read about people, you included who like using the
Barlow on the 90. Do you see any loss of image, as compared to just
using a lense without the Barlow? Also Meade claims the short Barlow
they make is better suited to the ETX, then longer Barlows like the
Teleview. What do you think about that?

Thanks again
John L.
Mike here: Adding any extra glass can detract from the image quality. But saying you don't need a Barlow with any telescope is like saying you don't need a second monitor on your computer. True, you don't NEED it but it does provide some convenience. Same with the Barlow Lens. As to what size will work best with the ETX-125EC, remains to be seen.

Subject:	 Eyepiece power
Sent:	Wednesday, June 9, 1999 9:23:12
From:	johnlat@earthlink.net (John R Latini)
Assuming the 125 is optically equivalent to the 90, only on a larger
scale, what do you think the maximum power to be used, should be?  A guy
at the RTMC suggested that 200X is the highest that need be used on a
125mm apeture Maksutov. But then again, I've read here, and elsewhere,
that people have taken the 90 up to 350X and got good results. Then
there is that 500X spec that Meade claims. I'm asking, since I'm
planning my eyepiece budget and strategy. I'll probably get the 82
degree Televiews.

Thanks
John L.
Mike here: The max mag is typically cited as 60x per inch of aperture, so 300x for the ETX-125EC. But as with many things, the max is actually somewhat in the eye of the beholder. There are a lot of factors; seeing, collimation quality, cleanliness, object brightness, amount of image degradation the viewer tolerates, etc. ETX-90RA and -90EC users have typically exceeded its "max" so one would expect that users will exceed 300x with the ETX-125EC.

Subject:	 ETX-125
Sent:	Wednesday, June 9, 1999 3:54:55
From:	KB3CNY@intergrafix.net (John J. Boyle)
Where can I find info on the ETX-125.  I see lots of references to it,
but no sources, etc.

Thanks,
  John
Mike here: Well, there is some info here on the ETX-125EC Feedback pages. Also, some dealers have posted some info.

Subject:	 ETX-90/EC vs. ETX-125/EC optics
Sent:	Tuesday, June 8, 1999 6:02:19
From:	JDeriso@Alphaind.com (Deriso, John)
Since I last wrote, I dug into this a little more.  The sites are
buzzing with comparison questions, so here's how I see it.
Comparisons Between ETX-90 and ETX-125: Magnification, True Field of View, and Relative Brightness May 7, 1999

 

 

ETX-90
1250mm Focal Length
90mm Aperture
ETX-125
1900mm Focal Length
125mm Aperture
Series 4000
Eyepiece
Apparent
Field
Magnifi-
cation
True
Field
Relative
Brightness*
Magnifi-
cation
True
Field
Relative
Field*
Relative
Brightness*
Relative
Magnifi-
cation*
6.4mm 52° 195X 0.27° 0.25 297X 0.17° 0.16 0.31 6.19
9.7mm 52° 129X 0.40° 0.37 196X 0.26° 0.24 0.47 4.08
12.4mm 52° 101X 0.52° 0.48 153X 0.34° 0.32 0.61 3.19
15mm 52° 83X 0.62° 0.58 127X 0.41° 0.38 0.73 2.65
20mm 52° 63X 0.83° 0.76 95X 0.55° 0.51 0.97 1.98
26mm 52° 48X 1.08° 1.00 (Ref) 73X 0.71° 0.66 1.27 1.52
32mm 52° 39X 1.33° 1.23 59X 0.88° 0.82 1.57 1.23
40mm 44° 31X 1.66° 1.55 48X 1.10° 1.02 1.93 1.00

  1. *Compared to ETX-90 with 26mm (48X) eyepiece.
  2. For the same eyepiece, the ETX-125 will have 27% more brightness, 52% more magnification and 66% of the true field of view compared to the ETX-90.
  3. Magnification = telescope objective focal length / eyepiece focal length
  4. Aperture ratio squared (125/90)2 = 1.929
  5. Relative Brightness = aperture ratio squared / relative magnification

  6. where relative magnification = (ETX-125 magnification) / (ETX-90 magnification)

Subject:	metal ball bearing ETX125
Sent:	Monday, June 7, 1999 16:16:24
From:	FjhDAVID@aol.com
I read thet the ETX125EC will have metal ball bearing. What does it
mean? What kind of advantages? Does it help for the drive accuracy
compared to the ETX90 nylon ball?

Thanks 
Francois

Subject:	 Re: One of your recent responses on 125EC page...
Sent:	Sunday, June 6, 1999 13:49:25
From:	mhoecker@concentric.net (mhoecker)
"Mike here: Until someone actually gets to work with one, hard to say
how much of an improvement things will be with ETX-125EC. Yes, you'll
get more light gathering power and a higher max magnification. But it is
supposedly about the same f-ratio as the 90 model (f/15 vs f/13.8). So
you may not see that much difference."

Reread The Backyard Astronomers Guide  (Dickinson & Dyer) on page 90
(Ten myths about telescopes and observing).  With both telescopes AT THE
SAME MAGNIFICATION, the 125 is STILL gathering twice the amount of light
as the 90 model.... therefore the image WILL be brighter,  just as an 8
inch, f/15 will be brighter than the 125EC --- at the same
magnification.

No real criticism here, just thought a clarification is in order.  I
enjoy your website... keep up the great job!
                                                                                                                        ...Mark

Subject:	ETX-125EC drive accuracy?
Sent:	Sunday, June 6, 1999 10:16:51
From:	FjhDAVID@aol.com
Do you think the ETX 125 drive motor will be stronger and more accurate
than the ETX90?

Francois DAVID
Mike here: If by "stronger" you mean will be able to handle the weight of the ETX-125EC, the answer would be "yes". But if you mean how much accessory weight could you add to the ETX-125EC before the motor began dragging, who knows. Probably not much. As to accuracy, I would expect similar tracking accuracy as with the ETX-90EC. Sometimes amazing accurate and other times not so accurate. Of course, it will depend a lot on the accuracy of the setup and alignment star selection (if using an Autostar).

Subject:	 my first telescope
Sent:	Saturday, June 5, 1999 8:12:28
From:	npny@gis.net (nelson)
i am thinking on getting this telescope, the ETX-125/ec.  What is the
price the telescope is going this days and where can i get it!.

Thanks,

Nelson
Mike here: As noted on the ETX-125EC Feedback pages, the price is $895. See Meade's web site for a complete dealer list.

Subject:	 125mm question
Sent:	Thursday, June 3, 1999 22:06:55
From:	johnlat@earthlink.net (John R Latini)
Since there is no actual scope to use, I was wondering how you or any
experts out there, might theorize on the Meade 125mm as compared to the
Celestron G-5, as far as image. Obviously this is all based just on
specifications and the laws of physics as applied to optics and
telescopes. What does anyone think the image quality might be?

John L.
Mike here: Given the quality of the optics of the ETX-90 models (compares favorably to the Questar 3" model), one would tend to believe that the ETX-125 would have superior optics as well.

Subject:	 ETX-125
Sent:	Wednesday, June 2, 1999 9:24:41
From:	johnlat@earthlink.net (John R Latini)
This is John again. I thought I would say a few things about the ETX-125
to add to the 125 users feedback area here. I was at the Riverside
Telescope Makers Conference and did talk with a few Meade reps and
played around with it. First thing, it sure looks nice, and is almost
identical to the 90. The 125 has metal bearings in one axis, where the
90 has nylon in both. The 125 has a right angle finderscope. The rest of
it looks the same. The most significant and obvious problem is the Meade
tripod. I have one on order with my 125, but now I will have to cancel
the order. It is just too flimsy to support the 125. I found a used
tripod with no head at the swap meet that is much sturdier, and I will
make an adapter and wedge myself. Anything is better than the Meade
tripod. It's hard to believe Meade would'nt make a more heavy duty
tripod for the 125. Some people say the tripod is not all that great for
the 90 either. Not much more to say. Meade told me the middle of June is
when it will come out, but someone here said July. I hope I'm right
instead.

Thanks
John L.

Subject:	 ETX 90 vs ETX 125
Sent:	Tuesday, June 1, 1999 8:24:26
From:	Rick.Happoldt@disney.com (Happoldt, Rick)
I have an ETX 90EC and am thinking about trading up to a 125EC.  I know
that the 125EC has twice the light collecting area, but how much of an
improvement visually do you think I will see?  Obviously faint deep sky
objects will be brighter, but how much more detail will I see on things
like the moon, planets, bright nebulae, and globular clusters?  I would
assume one could use the Celestron C5 as a reference point (though
contrast and sharpness will possibly be better with the Mak).

Thanks,

Rick
nicnrick@inreach.com
Mike here: Until someone actually gets to work with one, hard to say how much of an improvement things will be with ETX-125EC. Yes, you'll get more light gathering power and a higher max magnification. But it is supposedly about the same f-ratio as the 90 model (f/15 vs f/13.8). So you may not see that much difference.

Added later:

Thank you for the quick response.  Can you elaborate a bit on this,
though, as I want to understand the theory behind this.  Here is an
example:

Scope #1:  3.5" and f-13.5
Scope #2:  5" and f-15

Both scopes are using the same magnfication observing the same object. 
Which scope would show more detail, for example, on planets and which
would show more detail on Globular Clusters?  Are you saying that the
faster scope (f-13.5) would outperform or negate the larger objective of
the slower (f-15) scope?

I have been struggling with the comparison between aperature and f
number and have heard several points of view.  (not necessarily in
comparison between the two ETX scopes, one of which we don't have yet to
compare, but between other refractors, SCTs, etc)
Mike here: Take a look at John Deriso's comment on the ETX-125EC Feedback page for April 1999.

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Copyright © 1999 Michael L. Weasner / etx@me.com
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