Last updated: 31 January 2001

Subject:	 A complete Review and Field Test of the ETX 125
From:	sherrodc@ipa.net (Clay Sherrod)
(See end of review for photographs of Telescope and Viewing Modes)

My Meade ETX was purchased in December 2000 and the mechanical aspects
were completely checked and fine tuned within the first weeks of
purchase.  It presently tracks and slews with great precision and is
presently loaded with Autostar Version 2.1ek and Version A2.4 is
available for immediate download (I am awaiting favorable reviews).

This unit experiences NONE of the "creep after beep" nor random slewing
reported by some other ETX users.  This is partially attributed to:  1)
updating the Autotstar to Version 2.1ek; and, 2) operating the ETX 125
in Polar vs. Alt-Az mode.  The scope mounting has been fine-tuned to
remove all backlash, gear play and clamping problems reported in some
other Meade products.  When properly aligned at the beginning of the
night and initialized accurately for location, date and time, it is able
to retrieve objects dead center in a 40mm Erfle eyepiece in the main
scope after GO TO in High Precision Mode.

The optics of the telescope are absolutely the best that a manufacturer
can produce; as the owner (or previous owner) of:  a 6" Unitron
refractor, a 14" Celestron Schmidt, a 7" Questar, a 24"
Newtonian-Cassegrain (Arkansas Sky Observatory), as well as many other
types and makes of amateur and professional telescopes,  I can
qualifiedly attest to the perfect optics of this telescope.  It has
outperformed (in actual star tests on good nights) an 8" AND 10" Meade
Schmidt Cass.; it puts the 7" Questar to shame (also a Maksutov), and
routinely shows finer detail on moon and planets than MUCH larger
telescopes.  On Saturn, for example (same applies to other bright
planets), Cassini's division is routine; Encke's division is clearly
visible in both ansae on steady nights at 310x (12.4mm with barlow), as
is the Crepe Ring in the ansae as well as in front of the ball of the
planet;  four dark belts and the polar "cap" are routinely seen.

Double star resolution:  on January 21-22, the following double star
tests were done with the ETX 125 on Petit Jean Mountain under perfect
sky conditions and dark sky rated at 6.5/6.5.  A five-inch telescope is
rated with a Dawe's Limit of 0.9 for reference.
    CASTOR (beta gem) - current separation about 5 arc seconds (") but
    difficult due to the brightness of both components.  Easily spit
    into two equal magnitude components with conspicuous Airy disks at
    156x (26mm and 2x barlow).

    THETA AND (a940) - current separation 0.4" arc.  This is a test for
    10" or 12" telescope on a good night; the 8" Schmidt could not
    resolve or suggest that this star was double.  The star was CLEARLY
    ELONGATED (although not separated) in the 5" ETX, with the fainter
    star (mag. 6.0) appearing as a "knob" offset from the brighter (mag.
    4.8) star.

    TRAPEZIUM (star "d") - Star "d" in the trapezium of the Orion Nebula
    was clearly visible, although this may attest more to light
    transmittion than to resolving power.

    a16665 (PIS) - This is a very faint double for a 125mm telescope,
    requiring about 150x to resolve.  It is very close and faint,
    testing both the light gathering and the resolving power. 
    Components are 9 and 10 magnitude and are distinctly identified with
    the ETX 125
Deep Sky - A Test of Contrast and Light Gathering.  All telescopes are
physically limited by their apertures in the amount of light gathered;
nonetheless, what they DO with that light after they "gather" it
dictates the optimum performance (or lack thereof) for deep sky viewing.
 The light gathering power of the ETX 125 is rated at 12.5 for stars and
I would suggest around 11.1 for extended (deep sky) objects, of course
depending on extended angular size.
    ANDROMEDA GALAXY (M-31) - This was an absolutely magnificent sight
    on this night; having seen it many times before, I can honestly
    attest to the wonderful image, not equal to that perhaps of a 40"
    telescope, but one of the finest I have seen.  Keep in mind:  the
    sky for this review was absolutely black on a mountain rising 1,000
    straight up from the river valley below.  At 48x, (40mm wide angle
    Erfle), M-31 stretched completely across the field from one edge to
    the other; M-32 was clearly and brightly visible below M-31  in this
    field.  The star field was magnificent surrounding the two galaxies
    with MANY very faint stars adding an-imagined 3-D effect.  However,
    the BEST view came at 73x (26mm Erfle) where a very dark extended
    and curving lane could be discerned separating two arms of the
    galaxy near the core; this lane can be clearly seen in photographs. 
    Within the bright arms (2) could be seen many irregular brighter
    "lumps" of nebulosity although certainly no individual stars could
    be discerned.

    ORION NEBULA - As previously mentioned, the Trapezium stars (5)
    could be easily seen at 236x (15mm Plossl + barlow); the brighter
    four exhibited faint Airy rings.  The nebula impressive and
    extending across the entire field at 48x was filled with filaments,
    darkened areas and many faint stars.  The best view by far, allowing
    maximum contrast and resolution, came at 73x, where the "fishes
    mouth" and other extended filaments and dark nebulae could be
    clearly seen. As the eye became more and more dark adapted, the
    filamentary structure of the two "arms" curving from the Trapezium
    began to demonstrate considerable detail.

    MESSIER 35 (Gem.) - This is an easy object for any telescope, but
    many do not know that there is a more distant cluster imbedded
    within the view of this cluster.  NGC 2158 is an absolutely
    remarkable sight, seen through the star field of M35; at low power
    this appears very nebulous and unresolved, most stars being in the
    16th magnitude range;  however, at 236x, the ETX 125 revealed a
    "mottled" look to the cluster although no individual stars.  This
    cluster can NEARLY be resolved in a 14" f/10 telescope at 200x.

    PINWHEEL GALAXY (M33 - TRI) - This large galaxy can be seen clearly
    in the little 5 x 25 finder of the ETX 125 on this dark night.  In
    the telescope, the brightness is completely spread nearly evenly
    across the field of the 40mm; with the 26mm Erfle, the distinct
    pinwheel shape can be easily seen.

    CRAB NEBULA (M1 -TAU) - Although Messier's first, this is not an
    easy object for ANY telescope, easy to find only because of its
    proximity to the bright star Zeta Tauri.  At 153x, the Nebula takes
    on more detail; with lower powers it is a dull evenly-illuminated
    object.  Of course, no central star can be resolved.

    PLEIADES (M42 - TAU) - I checked the Pleiades for two reasons:  1)
    limiting magnitude test (I have a star test chart for faint star
    magnitudes within the bright star field) and, 2) field of view. 
    Limiting magnitude (stellar) for the ETX 125 is given at 12.5.  At
    236x during moments of very steady seeing, I reached a limiting
    magnitude repeatedly of 12.3 and - on very rare occassions - at
    times perceived one star listed at magnitude 12.7.  Regarding field
    of view, one becomes totally lost even with lowest powers,
    attempting to discern the distinguishing shape of the Pleiades; even
    the 40mm wide field eyepiece fails to get them all in; however, an
    LX 90 with the big 53mm 2" eyepiece, can, indeed get the entire
    cluster in the field.  Nonetheless, each of the bright stars (with
    the 26mm @ 73x) exhibit very clear and concentric (abour 4-5 each)
    Airy rings.  Perhaps a TRACE of nebulosity is exhibited with the
    40mm, but not impressively so.
OPTICAL COMA - The telescope was tested for visible coma at all
peripheral extent of each eyepiece; some coma (I believe induced by the
eyepiece itself, as I could get to rotate or change slightly by rotating
the eyepiece) was visible at the edges of the 40mm Wide Angle Erfle, but
not distractingly so.  With the 26mm Erfle, the 15.5mm Erfle and the
12.4mm Erfle there was abolutely NO coma visible at all, perfect star
images to the edge.

IMAGE FALL-OFF - An aspect important in photoelectric photometry is
image fall-off toward the edge of the field, where fainter objects/stars
become more difficult to see due to brightness loss.  The image quality
and brightness was tested doing faint star (as well as Messier 78 -
Orion) DRIFT across the field of the ETX 125; only with the 12.4mm WITH
barlow could any diminishing be noted, and that only with M78 and not
appreciable by any means.

CHROMATIC ABBERATOIN - None, absolutely none.  Even with the planet
Venus, there was little chromatic interference and this only when the
planet was very low in the western sky.  As a matter of fact, this was
perhaps the best view of Venus that I have experienced, with cusp
extensions visible far into the unilluminated portion of the planet and
conspicuous dark areas visible in the clouds along the terminator.

INTERNAL REFLECTIONS/BAFFLING - My ETX appears to be very well baffled
at the secondary and primary.  Stray light - except when viewing by the
first quarter and higher moon - is not a problem;  a test viewing a
faint star field and allowing Betelgeuse to drift slowly into the field
revealed a spurious brightening by the 0-magnitude star ONLY SECONDS
before it entered the field; likewise, as it exited, no trace of its
light could be seen within about 6 seconds.  However, at very high
magifications (256x and above), glare from Jupiter and Saturn COULD  be
seen with the planets out of the fields when viewing their satellites. 
In each case, the bright planet was immediately outside of the field.

TRACKING - I use my ETX 125 in both Polar and Alti-Azimuth modes, but
most definitely prefer Polar for four reasons:  1)  the sidereal
tracking is considerable more accurate in Polar, requiring a smooth
curve motion as opposed to "stair step" motion necessary for computerize
Alt-Az. operation; 2) hence, the amount of motor activity is
substantially reduced and very much reduces mechanical vibrations seen
easily at very high power;   3)  the slewing and GO TO function of the
telescope mount is much more accurate (High Precision); and 4) you
virtually eliminate some of the idiosyncracies of the Autostar (such as
the creep after beep drifting, and the "rubber band" effect where
Autostar wants to put you back where it had you before you center your

At any event, in Polar mode at the conclusion of my observing session I
wanted to test my tracking accuracy over a long period of time.  I spent
about 20 minutes early in the evening carefully polar aligning and
initializing my system; several alternate stars (I use the Easy Two Star
alignment method for Polar) had to be selected for my second alignment
star because of trees.  Once aligned, the scope seemed to track
extremely well.

There IS minor backlash drifting in Right Ascension at very high (250x+)
power, but not distracting and seems to be only occassional.  Even with
that, I centered Saturn at 310x (my gosh, what a beautiful view!!) while
it was just west of the zenith and watched it for a few moments as the
drive engaged for my recentering.  Once stablized, I went off and left
the telescope for 40 MINUTES (tracking on AC power);  to my absolute
amazement when I returned, Saturn was still absolutely centered in the
eyepiece, in spite of some 20 MPH wind gusts we were experiencing!  From
my observing deck at home in Conway, Arkansas, I frequently use the
Alt-Az mode for quick observations (conditions are very poor there).  In
the Alt-Az with careful alignment, THE BEST tracking I have ever
accomplished is 10-12 minutes, with considerable Altitude (Dec.) drift
and seemingly computer-generated stray motion.  It is still very
suitable, however, for routine viewing.

AUTOSTAR - When first getting the ETX 125, I was plagued with GO TO
function problems, "Motor Unit" failure readouts when slewing or
aligning, and considerable tracking errors once an object was found.  My
Autotstar came factory loaded with Version 2.0;  thanks to the help of
Dick Seymour and others, I was able to download Version 2.1ek over the
older version which eliminated many of the problems inherent with the
original program.  The GO TO function seems much more deliberate and
less "bouncy," and there is less electronic drift induced once the
object is found and centered.  I use High Precison during my observing
with Autostar, and the newer 2.1ek (and subsequent versions) assist in
that by identifying by NAME bright stars to reference in slewing to your
desired object; it also aids in initial polar or alt-az alignment, and
is essentially more "user-friendly" all around.

TRIPODS - I have given up on the Model #883 Deluxe Field Tripod for the
ETX 125; even in Alt-Az mode, the tripod in my opinion is simply too
light for a 17-pound $1,000 instrument.  In POLAR mode, it would be
telescope suicide to operate the -125 off of the #883 tripod.  For home
use I have made a very substantial pier that accomodates both Alt-Az and
Polar alignments; for field use I have upgraded to the Meade #887 heavy
duty tripod and wedge.  It should be recommended for the ETX 125; the
#883 is extemely risky with the heavy 5", but seems perfectly suitable
and proportioned for the ETX 90 in both alignment modes.

EYEPIECES AND VIEWING - I am frequently asked what eyepieces should be
used with the ETX 125.  I personally believe that most amateur
astronomers are "accessory hungry" and buy just about every gadget they
can.  You can have too many eyepieces.  For the ETX 125 I highly
recommended the following eyepieces:  40mm Plossl for very low
widest-angle viewing; 26mm (standard) Plossl for best deep sky (my
favorite eyepice); the 15.5mm Meade Plossl for deep sky and
planetary/lunar with the barlow; and, the 12.4mm Meade Plossl for high
power work.  I DO NOT use short focal length eyepieces for two important
    1)  very poor eye relief resulting in visual fatigue in a very short
    period of time;
    2)  loss of brightness and resolution.
I much prefer using the above-stated eyepieces (particularly the 15.5
and 12.4mm) with the "shorty" BARLOW lens, doubling the magnification. 
Believe me, I have tried short focal lengths that provide the same
magnification with the 15 and 12mm plus barlow combinations and the
results are by FAR better with the eyepiece/barlow combos.

I recommend the Meade eyepieces because 1) they are the best buy for the
price; 2) the quality is about the best you can get.  I also use the
Meade telenegative achrom. barlow.

POWER SOURCES - After much experimentation with a variety of power
sources I have come to some conclusions over the years.  First, use AC
power when you can, but MAKE SURE the source is reliable and steady and
that all your connections are firm; a loose connection can "glitch" your
Autotstar so that you will have to re-initialize from scratch and start
all over.  If you use DC power in the field, do not rely on the internal
batteries;  I use them only in "quickie" observations.  It is by far
better to use a good and powerful external DC power source in which a DC
line is plugged; lifetime and driving power are by far more reliable
than with the AA batteries.  By the way - NEVER use the internal
batteries for an Autostar download; use AC power whenever possible.  I
have experienced total battery failure more than once and have heard
from others who have as well.

FOCUSING - The issue of focusing any ETX is a hot one; the scope is so
small and the focus control is so close to the actual unit that focusing
without substantial vibration is impossible.  There are electric
focusers and flexible cables that enable you to get around that problem
and all work.  I use the Meade electric focuser through the Autostar,
which supposedly provides nine (9) focus speeds.  The new 2.1ek software
even tells you "rapid" or "fine" focusing depending on which number you
select!  However, even on "1" (fine), the focus is much too rapid and
inconsistent; sometimes it will be reasonably slow and sometimes faster.
 In any case, I am alway able to achieve focus even at high power with
NO VIBRATION and little effort.  I highly recommend some alternate
method of focusing other than the standard knurled knob.  Regarding
image shift:  only at very high speeds with the electric focuser (if I
forget to press for slower focusing) do I experience any image shift. 
Even then it is extremely minor; some of the earlier ETX 125's
experienced significant image shift but that seems to have been well
corrected at Meade.

So there is a complete field test of my ETX 125 on what I would consider
to be an ideal night.  The telescope was put on some pretty stringent
assignments and in my opinion more than passed all of them.  Sure, I
would like my mounting to be made of heavy cast metal instead of
plastic;  sure I would like to have nice bronze and brass and stainless
driving gears inside, and yes - I would like a larger finder.  But, for
the money....I'm very happy with what Meade packages in this little
stick of dynamite!  I admit that my telescope arrived in such a way that
almost left me in tears....the Alt. clamp would not lock, there was slop
in the Alt. drive; I could not get the Azimuth gears to engage (I wasn't
clamping tight enough), and the old 2.0 Autostar left a lot to be

But all that is fixed with minimal effort and maximum output for a
telescope that performs and behaves like an entire observatory that is
so portable and lightweight that it can be taken at a moment's notice to
the darkest recesses of space and imagination.

Did I mention that the Meade ETX 125 is every bit as good to look AT
than to look THROUGH?  It is a beautiful instrument, one to be proud of
at star parties, special events and even by yourself at dusk in the deep
woods awaiting nightfall.

It may not be perfect.....but it is MY ETX 125, fine tuned to MY
specifications and selections.  And, beyond a doubt, it is the favorite
of all telescopes I have used in my 32 years of astronomy.
P. Clay Sherrod
Arkansas Sky Observatory
Conway / Petit Jean Mountain

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