Last updated: 16 February 1998

Accessory Manufacturer Model Price
MotoFocus JMI N/A $100
JMI MotoFocusThe MotoFocus (shown in the photo on the right) is a battery-driven (2 AAA) motor that attaches to the ETX focusing shaft. The installation instructions are clear and mounting is straight-forward. You remove the focusing knob (an allen wrench is supplied along with an extra setscrew), attach the MotoFocus to the shaft, and tighten its setscrew. The cable is then attached to the Controller (the cable is visible in several photos). There is a warning in the instructions about the shaft working its way loose and disappearing inside the ETX. This will only occur if the setscrew is not sufficiently tightened. I would suspect this is also true with the focusing knob still attached but no such warning is in the Meade ETX manual.
MotoDec JMI N/A $100
The MotoDec (shown in the photo on the left) is also a battery-driven device (optionally using JMI MotoDec the same Controller as the MotoFocus). Again, the installation instructions are clear. The MotoDec attaches to the inside of the right forkmount using an existing screw. You simply loosen the screw, slide the MotoDec into position, and tighten the screw. You then place two of the four supplied rubber belts over the front declination control knob and over the MotoDec shaft. Connect the cable to the Controller and you're done. I had one minor problem mounting the MotoDec; one of the wires that go to the motor was not flush with the mounting plate but was instead perpendicular. I carefully bent the wire to be flush so that the mounting plate would be flush against the forkmount surface. Obviously I could have broken the connection but fortunately did not. I have alerted JMI to this problem and hopefully their quality control function will check for this in the future.

JMI ControllerIf you purchase the combination MotoFocus and MotoDec ($170) you get a dual Controller. If you purchase the MotoFocus or MotoDec by itself you get a single Controller. Shown in the photo on the right is the dual Controller. (Also visible in this photo is the wedge bubble level and above it the slot for the Controller.) There is a toggle switch to control either the focus or the declination motor. Just beneath the switch and to the left and right are buttons to activate the motor. Beneath these buttons is a dial to control the speed of the motor. JMI MF? Controller The photo on the left shows the Controller and the cables to the MotoFocus and MotoDec. The instructions indicate that the batteries are in the Controller but there is no information about replacing them. The back of the Controller is held on by four screws and removing these will provide access to the battery compartment.

I have found that by using the MotoFocus the vibrations seen when focusing by hand are essentially eliminated. In general, focusing is smooth although I have had some problems when trying to focus at the slower motor speeds. There are times when the motor will not activate. Increasing the motor speed will engage the motor. The MotoFocus is definitely a useful add-on. The MotoDec is another matter (at least that's my impression after limited use and this may change as I use it more). The MotoDec slews the ETX in declination whenever the Declination Lock is engaged. This is just like turning the Declination knob by hand. Reaching for the Controller and engaging the MotoDec is less convenient than just turning the knob by hand. On the other hand (no pun intended), if you want to move in declination as in an object search mode, then having a motorized declination drive is useful. The only problem I've had with the MotoDec is that there is some slippage in the belts; the declination shaft may not actually turn when the motor is first engaged. Changing the motor speed helps. [12/24] After several uses of the MotoDec I believe I have now discovered the culprit in the slippage. When the ETX's DEC control shaft is nearly turned to its completion rotation, it begins to tighten up. Even though the knob will still turn by hand there is enough friction to prevent the MotoDec belts from moving even though the MotoDec shaft turns. Backing off the DEC control shaft (as mentioned in the ETX manual) to a more middle position eliminates the slippage since the shaft will turn freely.

[12/23] When doing a polar alignment I discovered that both the MotoFocus and MotoDec interfere with being able to reach a 90 degree declination. When I first attempted to move the ETX to 90 degrees declination the MotoFocus housing touched the R.A. Lock knob. I carefully removed the MotoFocus and reattached the ETX focusing knob. Thinking I had solved the problem I again moved to 90 degrees declination. I got closer to 90 degrees but there was still an obstruction preventing reaching it. This time it turned out that the MotoDec cable connector attached to the MotoDec motor was hitting the ETX flip mirror control. Fortunately this was simpler to fix; it was just necessary to unplug the cable from the motor (which it is made to do). With the cable unplugged there was no further problem reaching 90 degrees and I was able to polar align the setup. Of course, I had to reattach the MotoDec cable and the MotoFocus but this took only a couple of minutes. One additional comment on the MotoFocus: I have found that when making large focus changes (as when changing eyepieces) using the MotoFocus is less convenient than doing it by hand. You have to get the controller, possibly toggle the motor control, and engage the proper button, and maybe adjust the drive speed depending on what you were last doing. This process can take a substantial amount of time to make a large focus move versus how fast it is to turn the focusing knob manually through an extended range. Of course, using the MotoFocus there is no vibration in the image. It would be nice to be able to manually focus with the MotoFocus attached to the ETX but you can't with the current design. I will continue to add further comments on these two add-ons as I use them more.

Piggy-back Camera Mount JMI N/A $50
JMI Piggyback Camera MountThe JMI Piggy-back Camera Mount is a product I've been waiting for and solves a need I was trying to find a solution to. Here I have this motor-driven equatorial mount (which tracks reasonably well) and there was no way to attach a camera to the drive or telescope to take wide-angle, long duration photographs of the night sky. This is such an obvious use that I kept wanting to come up with a way to mount my 35mm camera to the ETX. Well, JMI has an inexpensive solution. The installation instructions are simple. As shown in the photo on the right, the mount just slides over the ETX optical tube assembly (OTA). There is a bolt on the bottom to clamp the ring down. The ring itself is metal but there is a rubber cover to protect the ETX tube surface (thank you JMI). On the top of the ring is a large flat knob and the 1/4" screw to attach your camera. A counterweight is included and is attached to the ETX via a tripod mounting hole on the bottom of the ETX OTA. This is required to balance the ETX with a camera attached. In the photo, the Pentax camera partially blocks the Finderscope. This can be avoided by having the camera positioned a little to the right of vertical on the OTA. [2/1] I now have some short and long duration pictures using the Piggy-back Camera Mount. The counterweight works perfectly to balance the camera, no matter the position of the ETX. As shown on the Astrophotography - Sky page, exposures of 2 minutes come out beautiful. There are no obvious tracking errors. However, when attempting exposures of 5, 10, and 15 minutes, tracking errors became obvious. Whether this was due to a not-quite-perfect polar alignment (likely) or ETX drive errors is unknown at this time. I did see some declination drift on a guide star in the eyepiece on the 10 and 15 minutes exposures and I attempted to correct this drift every 5 minutes by moving the ETX in declination using the MotoDec. But on the film, the drift had already made its impact and so correction did not help. I will continue to take Piggy-back wide angle sky photos; watch for the results on the Astrophotography - Sky page.

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