Vincent Chan's Things Not to Do to Your ETX Page

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A great little scope, but sure can be frustrating to use in its stock configuration. I guess that's why there's such a large third party accessory market for it!

Here are some of the mod's & additions that I have made:

etx pictureThe assembled "machine" mounted on a tripod. Shown with the 8x50 finder and EZ finder. The stock ETX finder is still usable, and is attached in its original position (beneath the 8x50 finder). Also shown in the picture are the adjustable tripod wedge and the hand controller for the RA drive corrector.

finderAddition of a 8x50 right angle finder strapped to the OTA of the ETX plus an Orion EZ finder. The EZ finder attached via sticky tape while the 8x50 finder sits on two rails made of 1/2" square aluminum bar. The two rails are attached to the OTA via sticky tape and two electrical tie wraps. I can't recommend a good, large aperature finder enough. It makes hunting for those deep sky object so much more of a pleasure!!! (makes the stock 8x21mm finder seem like a waste of time)

wedgeThe home-made adjustable wedge, shown with the RA drive corrector hand controller. The design of this wedge is optimized for 40-50 degrees latitude, as it places the centre of gravity of the telescope over the centre column of the tripod for maximum stablility. It's made mostly of 3" wide by 1/4" thick aluminum bar. An threaded rod and hand crank allows for easy adjustment of the wedge at the viewing site, as well, an Manfrotto quick releas adapter allows for attachment of the telescope in seconds. A mohogony ledge at the back of the wedge holds two eyepieces.

RA drive corrector

One of the attractions of the Meade ETX is its built in drive motor to allow for tracking of cellestial objects. Unfortunately, when using the ETX at powers above 200X, it can be a bit of a challage. The time it takes to engage the motor, along with the amount of backlash in the gear set usually means the object you are looking at will drift out of the field of view (FOV) before the drive kicks in. Hence, the construction of the R.A. drive corrector.

 The hand controller will allow you to use either; the original drive circuit, supplying 1.8V to the motor, or to switch to the new drive circuit, where you can vary the voltage to 1.5 volts to 6 volts. With this I can fine adjust the tracking speed of objects such as planets, the moon or comets. (ex. with the R.A. drive corrector I was able to keep Jupiter, at 250X, at the edge of my FOV for over 30mins.) Also, I find, that at the factory settings, the ETX drive is a little too fast. It's also fun to play around, as you can move Jupiter around your FOV in the R.A. axis at will! A "TURBO" button is also added, to bypass both voltage control circuits, allowing you to quickly take-up the backlash in about 2 seconds. It puts about 8.3 volts across the motor. A 9V battery supplies the power and is calculated to last about 15 hrs. An additional switch on the ETX body allows for the use of the original power supply and circuit as a backup.

gutsModifications and conections to the
ETX base printed circuit board.

hand controllerThe assembled hand controller
shown with the new 9V battery
installed into the base

schematicElectrical schematic for the drive corrector. BIG DICLAIMER: a few modifications must be made to the original circuit board. This will definitely VOID your warrenty! I CANNOT guarantee that this circuit will work or not burn out the ETX drive motor. (There's a reason I went into mechanical engineering and not electrical!) This is not for the squeamish. If you don't understand why and how this circuit works, don't even attempt these modifications. I will not take responsibilty for any damage you may do to yourself or your ETX. I've only put the schematic here at the request of other ETX'ers around the world.

ETX + QuickCAM VC pictures

Here are a few pictures taken with an ETX + QuickCAM VC (colour internet camera)

Picture of Venus. Small cresent.


Mars, slight whitening at the poles is visible, black "canal" strip through the middle.

Jupiter, with two cloud bands visible.  This is better than any picture that I've have taken on film with my OM-1 and ETX!

Saturn, with shadow visible on the back rings.

All photo's taken with the QuickCAM connected with the Meade photo tube onto the back port of the ETX, ie. no eyepiece projection.

sunspotsSunspots, hard to believe each of those spots are larger than the Earth! Thousand Oaks Polymer Plus filter. (ps. some of those spots are on the CCD, forgot to clean the darn thing!)

flowerA small impatient flower bud, about 20 feet away. Taken through my living room window. Not a bad "macro" lens.

  • For great infromation on the Meade ETX & accessories I recommend a look at Mike Weasner's ETX page
  • Thanks to all you out there in the internet ETX-land for their help in figuring out the R.A. corrector circuit.
  • This ETX site owned by Vincent Chan 
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  • Created: Sept 17, 1998
    Updated: July 20, 2008