iOptron ZEQ25GT Review/ Everything you Should Know Before Buying it

iOptron ZEQ25 Reviews

After reading some positive iOptron ZEQ25GT reviews, I figured it would be an excellent mount for astrophotography. It was said to be light but with a good payload, accurate, and fast to polar align. My intention was to utilize the ZEQ25GT in conjunction with my Orion Eon 80mm refractor for deep sky photography and a 9.25′′ Celestron SCT for planet imaging. This article contains my early thoughts on iOptron’s one-of-a-kind Z-designed equatorial mount.

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When I started looking for the ZEQ25, I had a few alternatives to choose from. Here are some of the options I saw online:

  • Mount with 1.5″ tripod (no polar scope)
  • Mount with a polar scope and 1.5″ tripod
  • Mount with polar scope, hard case, and 1.5″ tripod
  • Mount with a polar scope and 2″ tripod
  • Mount with polar scope, hard case, and 2″ tripod.

I chose the final one with the polar scope, hard bag, and 2′′ tripods. My intention was to ultimately transport this equipment to a dark sky location for deep space astrophotography. The hard case would be ideal for moving the mount, and the 2′′ tripods would be more stable than the 1.5′′. The polar scope was essential for reducing setup time.


The ZEQ25GT was quite simple to assemble. Like many configurations, the mount connects to the tripod via a threaded center rod that runs through the accessory tray and into the bottom of the mount. When the center rod is tightened, the tripod legs expand to steady them while the mount is secured to the tripod. I put everything together in a matter of minutes. However, setting up the ZEQ25 for the first time was a fascinating experience! The Z-shaped design seemed strange at first since it differed from a German Equatorial Mount. I had to double-check the user instructions to be sure I did everything right! According to iOptron, the “Z” design mount places the payload’s weight near the center of gravity, providing for more natural stability. Here are some images of two iOptron mounts. The first is the ZEQ25, which has a Z-shaped design, while the second is the iEQ30, which features a typical GEM design.


The ZEQ25 balances the load incredibly effectively, in my opinion. Once balanced, the mount is very smooth in both R.A. and DEC. The only time it wasn’t properly balanced was when I used my 6′′ Meade SCT with finderscope. The finder scope is skewed to one side and hefty enough to affect the balance. I rectified this by removing the finderscope and replacing it in the middle with a lightweight Orion EZ Finder II Telescope Reflex Sight.


Here’s something you should be aware of. The ZEQ25 saddle includes a ridge along one side that may grab the dovetail of your optical tube, giving it a secure feel. The optical tube seems to be snug in the saddle, but it may really slip out. When I was balancing the mount, something occurred to me. Fortunately, my lightweight optical tube landed safely on the soft grass. The saddle was designed in this manner by iOptron to accept non-flat dovetail plates. The issue may be solved by filing a bevel on this ridge using this approach. I ended up adding an ADM replacement saddle, which solved the issue.


The ZEQ25 employs gear switches to decouple the worm from the worm gear, allowing the mount to swing freely in R.A. and DEC. It also has tension adjusters for fine-tuning the mesh between the worm and the worm gear for the best performance. This takes some getting accustomed to! To manually slew the mount in R.A. or DEC (for example, to balance the mount), the tension adjusters must be relaxed, which takes many turns. The gear switch is then opened to remove the worm from the worm wheel, allowing the mount to swing freely. For locking the axis back, the procedure is reversed. The goal is to apply just enough tension to eliminate any gear play while minimizing stress on the worm assembly. In contrast, a German Equatorial Mount uses simple clutch locks to release and engage the gears.

The following information about the gear switches and tension adjusters is provided in the user guide:

The Tension Adjusters are used as the last step to lock the gears and the first step to release them. Release the Tension Adjuster first before disengaging the gear system. Turn the Gear Switch to the OPEN position. When using the gear system, first set the Gear Switch to the LOCK position. After that, tighten the Tension Adjuster. During operations, never completely tighten the Tension Adjusters. Screw in the Tension Adjuster completely, then back out by roughly 2 turns. The optimal place varies according to the circumstances, but it is usually between 1-3 turns of the completely tightened position. It should ideally be at a position just deep enough to eliminate any free motions (plays) while minimizing strain on the worm assembly.

This procedure is simple to learn and allows for customization of the gear mesh to enhance performance. I’m simply used to the standard clutch locks on a GEM!


I had read that the polar scope on the ZEQ25GT was one of the finest in the industry before acquiring it. I can see why now! The lighted reticle of the polar scope is based on the radius and angle of the star Polaris (or Sigma Octantis in the southern hemisphere) from the true center of the pole. Please see the picture below. A satisfactory polar alignment may be established fast as long as the mount is level and the time and site information in the handset are accurate.

However, when I initially used the polar scope, the image was blurry. I was let down by the somewhat fuzzy image. But I immediately realized it had a focuser, as demonstrated below. This was not addressed in the ZEQ25 user handbook. The view was extremely clear after changing the polar scope focus!

The ZEQ25 hand controller indicates where Polaris should be on the LED reticule of the polar scope. By hitting the MENU button and then choosing “Align” and “Pole Star Location,” you may see the current Polaris position on the reticule. However, thanks to a suggestion from Paul Chasse, a well-known specialist in iOptron mounts, I discovered a better method to achieve this. Paul may be found on several forums offering assistance and lessons on different kinds of astronomy equipment, mainly iOptron items. Paul also sells iOptron mount upgrade accessories including the ZEQ25 Altitude Locking Knob, ZEQ25 Dual Spring Kit, ZEQ25 Oversize Knob Kit, ZEQ25 Polar Scope Spacer, and ZEQ/iEQ30 Padded levelers.

Paul was assisting me with my polar alignment one night when he said that he used the iOptron Polar Scope software for iPhones and iPads. I required a separate app since my phone is on the Android network. I discovered Polar Finder by TechHead. It offers a selection of telescope mounts, including iOptron. This software makes it simpler to determine where Polaris should be on the reticule than the ZEQ25 hand controller. Using this software, I simply adjusted the ZEQ25’s azimuth and altitude knobs to put Polaris in the same location on the polar scope reticule as given by the app. The first time I used the program, the outcome was pretty thrilling! Polaris persisted in the center of the eyepiece field of vision for many minutes with a 12.5 mm eyepiece (and f/10 scope) before there was enough drift to detect.

Because the polar alignment wasn’t functioning so well after a few uses, I believe my polar scope may have moved within the mount over time. I ended up using the BrightStar Polar Alignment feature on the handset. This took a little longer than using the polar scope, but it was a simple procedure. When I polar oriented the ZEQ25 in this manner, Polaris was nowhere to be seen in the polar scope. I called iOptron Support, who gave me instructions on how to re-align the polar scope. I have not tested it as of this writing. I would say that iOptron’s support is among the finest I’ve encountered for astronomy equipment! This is something I’ve heard others say.


The ZEQ25GT has a maximum payload capacity of 27 pounds. So my idea was to utilize my 9.25″ SCT on it for planetary imaging. The 9.25″ weighs 20 pounds and with a tiny planetary camera (such as ZWO ASI120mm), focuser, finderscope, and TeleView 2.5X Powermate, it should be slightly below the cargo limit. I understand that the maximum payload capacity of any mount is intended for visual astronomy rather than astrophotography. However, I had heard that the ZEQ25GT handles big loads close to or even above the limit quite effectively. I was eager to give it a go!

I noticed after attaching the 9.25′′ SCT to the ZEQ25GT that this tube was too wide and hefty for this setup! It felt WAY under-mounted to me. Maybe it’s because I was accustomed to my SCT being mounted on the sturdy CGEM that I used previously. Even when it was balanced, it made me really uneasy on the ZEQ25GT. I instantly deleted it. I ended up purchasing a 6′′ Meade SCT, which looked ideal for the ZEQ25GT, as well as a 90mm Orion EON.


The user guide refers to the mount’s zero position, which is the default R.A. and DEC axis point. The mount is in the zero position when the counterweight shaft is pointed to the ground, the telescope is at the highest position with its axis parallel to the polar axis, and the telescope is pointing to the North Celestial Pole, according to the user handbook (if you are located in the northern hemisphere). I was startled to see that the mount did not include any index markings to make this a simple and precise operation.


I found the hand controller on the ZEQ25 to be quite simple to operate. The UI seems to be highly user-friendly for both setting up and running the mount. The only problem I had during my first testing of the mount was that the hand controller did not save the date and time. When I initially switched it on, the display was set to 2011-01-01, and the time was wrong by many hours.

Every time I switched on the mount, I had to enter the right day and time. Everything was OK as long as I kept the mount on. However, the ZEQ25 instructions state that following polar alignment, the mount should be returned to the zero position, as should the hand controller. According to the instructions, the simplest method is to switch the scope off and then back on. However, this would reset my hand controller to the incorrect date and time. In any case, it was discovered that the battery within the hand controller was low. This was simple to replace. The hand controller’s rear cover is removed using four screws, and the battery is changed. The battery is a standard button battery (CR1220). It kept the date and time when I changed the battery.


As with many telescope mounts, the coiled wire for the hand controller does not stretch long enough for easy usage. It’s not too horrible if you’re right next to the scope, but if you’re sitting at a laptop two or three feet away and attempting to use the controller, it’s a little tough to deal with.


The ZEQ25GT is a great mount in terms of mobility, setup time, accuracy, and smooth operation. I was able to utilize it for the astrophotography of Saturn with my 6′′ Meade SCT. While I was recording the movie, the ZEQ25GT performed an excellent job of keeping the globe centered. As of this writing, I’m not sure I’ll maintain the ZEQ25GT since I want to go back to a beefier mount that can support my 9.25′′ SCT better. However, for those with a lighter setup, such as a refractor, I strongly prefer the ZEQ25GT for deep-space photography. I didn’t get an opportunity to put the tracking to the test, but I’ve heard it performs well. The following are my thoughts on the ZEQ25GT’s pros and cons. I hope you found this review useful. Please leave your thoughts in the comments section below.


  • Very light; easy to transport
  • The decent payload for light mount
  • Very smooth and balances nicely
  • Polar scope makes it easy and quick to perform a polar alignment
  • BrightStar Polar Alignment is easy and fairly accurate
  • Goto’s accurate
  • Fairly quiet during slewing
  • Control over gear mesh with switches and tension adjusters
  • Very straight-forward operation of the hand controller
  • Excellent tech support by iOptron
  • Great tutorials available by Paul Chasse


  • The optical tube can fall off due to ridges on the saddle plate
  • The hand controller cord is too short
  • Cannot look directly down on bubble level. The mount obstructs the view slightly
  • No index marks on the mount for lining up at the zero position
  • Gear switches and tension adjusters take time to get used to
  • GPS takes several minutes to sync

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