Meade ETX-125 UHTC Follow-up
by Duncan Rosie
I have no affiliation with or commercial interest in any of the companies mentioned
in this review, nor any of their distributors or resellers.
Introduction
Since posting my
original review
of my Meade ETX-125 UHTC eighteen months ago I have received numerous
emails enquiring about the continued performance of the little scope and asking
whether I am still happy with it.
Let me start by saying that I am still very pleased with this telescope and
it performs very well, punching well above it's weight in my opinion. It is
a favourite at star parties and invariably offers the sharpest views of the
planets and Moon when in the company of 8" SCT's and similarly priced dobs.
This follow-up describes my experiences with the ETX as well as some techniques
and accessories I've found useful. A lot of what I'll say here is echoed in
the ETX discussion forum here on Cloudynights and any new ETX user or prospective
owner will do well to browse this forum.
My ETX did not have an auspicious start:
* The dreaded "Motor Unit Fault" was frequently seen,
* GOTO was pretty hit or miss, and then
* The RA drive bracket cracked.
These very common issues are all discussed in the original review and have
all been resolved and have not re-appeared.
Motor Unit Fault
The "Motor Unit Fault" on my ETX was related to the cracked drive bracket
- since the motor assembly was replaced by Meade this has not been an issue.
When I remounted the motor unit I did leave out one of the screws to allow
the unit to "centre" itself more easily in the worm drive shaft - this
prevents it binding on the shaft which was the cause of the initial problem.
I don't recommend you do this as your mileage may vary, but it has worked
for me.
GOTO accuracy
This depends primarily on four things that should be done at the start of
EACH observing session:
- Don't use the internal AA batteries, rather run from a 7Ah or larger power
tank type battery pack.
- CALIBRATE MOTORS!
- TRAIN DRIVES!
- Level the tripod/fork base and also level the optical tube with a spirit
level.
Finding an accurate North is also important (and not that easy down here in
the Southern Hemisphere), but following the four steps above will pretty much
solve most GOTO issues. Quite often the alignment stars selected will seem quite
far off in the finderscope but once centered and the "Alignment successful"
message appears the GOTO accuracy is good from then on.
What can be seen with an ETX-125?
There are many positive observing reports on the ETX forum lauding the
ETX's ability to resolve separation in double stars, detail on planets and detail
on the Moon, globular clusters, etc.
The major determinant in what you can see with your ETX is not the eyepieces
or accessories, it is the quality of the sky you are observing under. From my
backyard in light polluted Durban, South Africa, I can't find 47 Tucanae with
the naked (glasses assisted) eye but it is an impressive globular that is quite
bright in the eyepiece. On a moonless night at Hotazel in the Southern Kalahari,
47 Tuc is easily seen with the naked eye and is quite overwhelming at the eyepiece.
At Hotazel the Milky Way stretched from horizon to horizon across the entire
Western sky. With a completely unobstructed view in all directions, I let the
"Tonight's Best" guided tour take over and the ETX found EVERY object (I
did skip the black holes and quasars) in the FOV of the Meade 15mm QX 70¡ eyepiece.
I saw more that night than I have in the last year or two, simply amazing.
The ETX is not great at nebulae, the f/15 focal ratio and 125 mm aperture do
not make this a widefield light bucket. Side by side, my old Orion 90 mm f/10
refractor offered better views of Eta Carinae and the Orion nebula than the
ETX-125 using the same Scopetronix 40 mm plossl. Obviously a decent widefield
eyepiece like the 24 mm Panoptic would help, but if nebulae are your thing then
have a look at a fast dob!
I had the opportunity to do a side by side comparison under reasonably dark
skies at 1600 m altitude with an Orion XT10 Intelliscope. On the Orion nebula
(using a 24 mm Panoptic in both scopes) the ETX was blown away by the dob. However,
on the Trapezium (with a 13 mm Nagler T6) it was a different matter and the
ETX easily found the E component and one observer claimed the F component with
averted vision but I couldn't see it.
Eyepieces for the ETX
This is a hardy perennial on the ETX forum and there is also a lot of info
in the Eyepieces section on Mike Weasner's excellent site at http://www.weasner.com/etx
- here are my impressions of eyepieces I've used on my ETX:
* Meade eyepiece kit - a bargain at $99 and my favourites in this
bunch of plossls are the 15 mm down to the 6.4 mm. The latter is quite useful
for me on the planets as my eyesight (such as it is) prefers image scale to
anything else. At 300x the 6.4 mm can offer sharp views when seeing permits.
I am not fond of the 32 mm and 40 mm, preferring the Scopetronix 40 mm which
I have which has superior coatings, adjustable eyeguard, and doesn't black out.
* Meade QX 70¡ series - I have the 15 mm which is small, light and
offers sharp, contrasty views at night. It is my preferred general purpose eyepiece
in the ETX. It does have some gunk in it which is visible when observing the
sun. Most of the budget-minded widefield eyepieces are not favourably reviewed
in faster telescopes, but at f/15 the ETX simply doesn't show up the major flaws
of these designs and they are excellent choices for this telescope.
* Televue Panoptic - I had the pleasure of using a 24 mm for an evening,
fabulous eyepiece, the ETX loves it and so do I.
* Televue Nagler - on the same evening of the 24 Pan I got to use
the 13 mm T6 - you can think up your own superlatives here, they will all apply!
I haven't had the chance to use any orthoscopics yet and would love to try the
UO series and the TMB/Burgess planetaries in the 10 - 5 mm range although I
suspect that the 7 mm would offer the most image quality for magnification in
the ETX.
Accessorise your ETX!
If you enjoy upgrading,
fiddling, adjusting and experimenting then the ETX is the telescope for you.
A visit to the Scopetronix web site reveals a whole host of bits and bobs
you can get specifically for the ETX. Here is what I have succumbed to (so
far):
* Meade ETX dewshield - an essential, this should be a standard
item. This plastic dewshield screws onto the front of the ETX and is effective
at keeping stray light and dew of the corrector plate. It could be improved
by some internal baffling and a less reflective surface but it works well
nonetheless.
* Scopetronix Flexfocus - another essential. This greatly reduces
the focusing wiggles (vibration, but not image shift due to mirror movement)
and makes focusing much easier, especially near the zenith.
* Webcam adapter - see the astrophotography section below.
* T adapter - ditto.
What I plan on getting next includes vibration reduction pads, piggyback
camera mount, 4 in 1 Multi-mate alignment tool, accessory tray (for the Autostar
bracket) and a screw in solar filter (I have a home made Baader film equipped
one which does the job but doesn't quite look the part). A good pair of 20x80
binoculars will hopefully see off most of the wide field yearnings!
Photography with the ETX
A check through the ETX and photography forums here on Cloudynights will
show that some intrepid individuals are taking fantastic astrophotos with their
ETX as the optical train and tracking platform. This must take them a lot of
time, practice and patience for I must confess that my astrophotography attempts
have been, as yet, decidedly unspectacular.
I don't think the ETX mount was designed with any kind of imaging in mind:
* In Alt/Az mode there is no clearance for a camera unless it is
mounted at the eyepiece.
* In Polar mode the whole thing looks like it is going to fall over
at any moment (not to mention the latitude adjustment in 5¡ increments).
I have attached my Logitech 4000 webcam and imaged Jupiter with some success
and have also directly coupled my Olympus E-300 and imaged the Moon but struggled
to achieve accurate focus (over several attempts, including using a Hartmann
mask, mirror lock-up, etc.). I need to spend more time at this, practice, and
learn to be more patient. Alternately, I should probably sell the house, car
and kids and invest in a second setup (like a TOA-130, EM200 and SBIG camera,
hmmmÉ might have to sell the dogs as well.).
My next attempts will be to piggyback the E-300 to the ETX and try some unguided
short exposure shots and some guided (with the webcam in the eyepiece as the
guider) longer exposure shots, sometime when I have the time and am feeling
patient enough. It does make a superb 1900 mm f/15 telephoto lens for daylight
use.
What Meade could do to improve the ETX
IMHO, Meade should have addressed the following on the ETX when they released
the Premier Edition:
* Decent gears - the plastic geartrains and motor mounts used are
not good and are the source of Motor Unit Fault problems, backlash, poor response
at slow slewing speeds, and GOTO inaccuracies. I emailed Pete Peterson of Peterson
Engineering to ask if he had an equivalent Bucks Gears for the ETX but he doesn't,
pity.
* Better fork clearance - not only for rear mounted accessories but
also for easier focusing and to allow the OTA to be mounted further back for
better balancing.
* Better (more accurate and more stable) implementation of Polar
mode on the tripod.
* Sliding dewshield - a dewshield shouldn't have to be an accessory.
* Bracket for the Autostar handbox!
What Meade have got right with the ETX
Again, IMHO, the reasons I love my ETX are:
* Outstanding optics and optical tube.
* Autostar - it has it's detractors but I find it easy to use and easy to update.
* Portability - it's not aircraft carry-on proportions, but it fits into the
smallest car and the decision to take it on a trip is a no-brainer.
* Set-up - even with CALIBRATE MOTORS and TRAIN DRIVES (capitals intended) it
only takes five minutes.
* GOTO - with proper set-up the electronics manage to overcome the flaws of
the geartrains to provide accurate and repeatable slews to all sorts of wonders
in the night sky.
