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The iOptron MiniTower - A Second Opinion

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by John Cameron

Like many of you, even though I have more telescopes and mounts than I can practically use (just ask my wife), I am always in the market for new and more sophisticated equipment. Hence, I have for some time been looking for an automated alt-az mount to replace the hand-operated one that I use with my 5.1-inch (105 mm) refractor, as well as those I use with my 90 mm refractor. Having read the favorable reviews that the iOptron MiniTower received, I decided to purchase one and for, good measure, the iOptron Mini Cube Pro as well. The MiniTower was intended for use at our mountain home, where I spend a few weeks every year, and this is the story of my experience with it. I will review the Mini Cube Pro later this spring.

I purchased both from a well known dealer; the MiniTower preceded my arrival in the mountains by about three weeks. Fortunately, my wife was here to take custody (I "forgot" to tell her about my purchase; she thought what UPS laid on our doorstep was a roof rake). When I arrived, the first thing I did after unpacking was, of course, to check out the MiniTower. It came in two separate boxes—one containing a reasonably sturdy metal case in which the mounting head, controller, counterweight/second telescope arm and various cables were neatly packed. The tripod and 11-pound counterweight were packed in the second box. It was wise of iOptron to pack the counterweight with the tripod and not with the head and controller, either of which could have been damaged if slippage had occurred. All of the equipment was in excellent condition.

After removing the various components from the box, I printed the so-called instruction manual from the enclosed mini-compact disk, and began putting the mount together. It is no exaggeration to say that the instruction manual is incomplete and, in at least one case, inaccurate. Anyway, having succeeded in assembling the mount, which requires various threading and adjustments, I added the counterweight and locked the telescope to the assembly (my refractor had a 1.5-inch dovetail plate attached, which seemed to work perfectly well, even though the instructions suggest a 1.75-inch version) and balanced it (more on that later). Then I began programming the controller. At the appropriate point, per the manual, I pushed “to park position,” and waited for the motors to engage as the manual said they would. Nothing happened. So, I manually aligned the scope in a vertical position, using a level to ensure precision, pushed "to park position" again, and shut the power off. Then, I breathlessly waited for it to get dark.

Here is a photo of the mount and telescope, properly aligned in the "park" position:

The “new telescope rule” must not apply in the case of mounts, for that evening was brilliantly clear, and I looked forward to an enjoyable night under the stars. Once powered up, the internal GPS quickly locate the satellites it was seeking. And in just a couple of minutes, it locked on them. I selected the “one star quick align” and pushed “enter.” Nothing happened, except that the controller told me to align the star in the center of the eyepiece and push “enter” again (I learned later that the MiniTower, when used in alt-az, only slews to alignment stars using the two-star alignment function). So I decided to slew the telescope to the alignment star using the hand controller. I pushed the “down” button and the “slew right” button. The telescope began to slowly move down, but it did not move in azimuth. I tightened the azimuth lock, loosened the azimuth lock, and unmounted and remounted the head, but it would not budge in azimuth. I took the mount inside, tried a different power source and a warmer climate, but it would not move in azimuth. Finally, I loosened the azimuth lock and manually swiveled the head to and fro several times, tightened the lock, and once again tried to slew it electronically. It jerked a couple of times to the right, then stopped. That was it—there was no more movement in azimuth. The mount was obviously defective.

Here are photos of the various knobs that require tightening, including the azimuth lock:

I telephoned the dealer the next morning. To the dealer’s credit, they agreed to send me a new one without further delay, as well as a UPS prepaid return slip. The new MiniTower arrived in a few days.

Assembling the new mount was much easier, since I was familiar with the process. I should note that, once again, the mount arrived well-secured and well-packed. Following setup, I turned on the power and tried slewing. Hooray! It slewed freely in both altitude and azimuth. But slowly. To adjust the slewing speed, I looked for the "speed" button described in the manual, but it was nowhere to be found. It turns out that there is no speed button, and that the slewing speed is adjusted by simply pushing one of the number keys.

And as luck would have it, a clear night was once again in store. Wanting to be sure that nothing went wrong this time, I very carefully balanced the telescope by loosening the altitude lock, picking a mid-weight eyepiece, extending the focuser to a typical length, loading the finder, and extending the dew shield. After a few adjustments, the scope balanced perfectly, and I tightened the altitude lock.

At dusk, I powered the mount up and waited for the internal GPS to locate satellites. After waiting for what seemed to be forever, I gave up and slewed the telescope to the west, where the two-day-old crescent moon and a brilliant crescent Venus were setting side by side—large crescent and small crescent, both with horns pointed skyward. I watched this magnificent sight for about 40 minutes until the planet and moon were so low on the horizon that the view was no longer good, then shut the mount down, and went in for dinner.

After dinner, I decided to try the MiniTower on stars and deep-sky objects. I powered it up once again and waited for it to find satellites. Waited and waited. After what again seemed like an inordinate amount of time, I decided to go in and read a book while it was searching. Finally, after about 25 minutes, I returned and found that the satellites had been located. Wondering why it took so long and recalling that the previous mount had not only quickly located the satellites but, once locked in, when turned off and back on, found them instantly, I decided to test the mount. That was a mistake. Twenty-five minutes and a few chapters of my book later, it again located the satellites.

Using a 27 mm Panoptic eyepiece (22.6x), I slewed to the alignment target, pushed “enter,” and voilà, the mount was aligned. I then slewed to a number of other winter sky targets and found that the “go to” feature of the MiniTower is quite accurate. In every case, the object was within the field of view up to 27 mm eyepiece. I did notice that the mount had a tendency to slew clockwise much more often than counterclockwise. Hmmm. A Problem? Anyway, I decided to change eyepieces, moving from a the Panoptic to a 6 mm Radian, together with the requisite 1.25 mm. adapter. I had no sooner attempted to place the smaller focal length eyepiece into the adapter on the telescope than the alt clutch slipped, causing a loss of alignment. Angry, cold and frustrated, I retired for the night.

The next day, I did extensive Internet research and found very much opposing views concerning the MiniTower. Some owners say it is terrific; others have had problems. One noted problem was with the azimuth gears; another with the GPS. Various website entries explained how to fix the GPS. But rather than risking receipt of bad advice from the Internet, I called iOptron and talked with a nice technician, who verified the recommended fix—remove the top plate and be sure all electrical connections are in fact connected, and when they are, jiggle the wires. I did that, replaced the top, repowered the mount, and the GPS worked to perfection. I also asked the technician about the slipping of the vertical axis clutch. This was on a Friday. He said he would have to check with someone and would call me back on Monday. As I write six days later, I have still not heard back from iOptron, despite my having left a reminder message on Monday.

But once again, a clear night was in the offing, and when darkness arrived, I repowered the mount, aligned it, and slewed around to a number of objects. Once again, the “go to” was very accurate. However, the mount continued to slew far more often in a clockwise direction, and the power cord ultimately became fully wrapped around the mount head. Yup, a problem. How to undo it? Two choices: slew the mount counterclockwise three or four times using the hand controller or disconnect the power and unwind the cord, reconnect the power, and realign the mount. This is something that iOptron really needs to address.

Next, I decided to see if Rigel’s companion was visible and moved the scope to that star and put on power, using a 3 mm. radian (203.3x). No alt slip this time, perhaps because I tightened the alt lock with as much strength as my weak arms could muster, or perhaps because I was very careful. To my surprise, having only used the 27 mm. panoptic previously, the image jumped around the Radian's field of view. At first, I thought the tripod might be unsteady (some Internet commentary questioned the stability of the iOptron-supplied tripod). But that was not the case. Mounted on anti-vibration pads (the MiniTower has neat little rubber feet that fit perfectly into the pads) and properly secured, the tripod was quite steady indeed. No room for criticism there. As the mount made a humming and then bumping, and then humming and then bumping, noise, I next suspected that the problem might lie in the gears. However, by this time Rigel was not high in the sky, and I also thought that it could be the atmosphere (seeing in the mountains is often not good, particularly as objects fall down from the zenith). So, I shut the mount down and again retired.

Note the anti-vibration pad:

The succeeding night also began clear, and I decided to further test the steadiness of the mount under power. I slewed the scope to the moon and again, using a 3 mm. radian, saw the moon jump around in the field of view. Obviously, something was wrong. I also noticed that when using the controller at speeds of 64X, 16X, 8X, etc., rather than slewing smoothly, the mount jumps across the sky. And so, I was disappointed. Both the sky and my mood turned cloudy, so I packed the scope, mount and accessories up

Before concluding, I must confess to being a gadget geek and a bit of a perfectionist. Much of my equipment is high-end, and I like things to work properly.

The bottom line? The iOptron MiniTower has enormous possibilities, but the two I received were not up to par. If the MiniTower worked properly, it would be a bargain at the price offered. iOptron gives a good two year warranty on its products. However, iOptron appears to have quality control issues. I am advised that the problems I experienced are readily repairable and could have been caught prior to delivery to the dealer. It would be worth this young company's while to invest in better quality control and, perhaps, individual unit testing. While that might add a few dollars to the cost of the product, most astro-consumers I know would rather pay a little extra for something that was relatively certain to work properly. In any event, while the mount may be marginally suitable for visual use (or even better, depending upon your level of tolerance and the quality of the particular unit you receive), I do not recommend it for astrophotography.

Corollary: I  learned that Steve Forbes operates a company in New Hampshire called Trapezium Telescopes & Services that regularly services iOptron products and has developed an upgrade that, for a fee, may cure the problems to which I have referred. I had a lengthy talk with Steve; he is going to lend me one of his “fixed” iOptron MiniTowers so that I can compare it to the two I received. I will supplement this review with the results of that test.

And so my story is to be continued….

GRAPIDS 233248v1

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