How to Set Up & Use EQ Mode on the ZWO Seestar S50 & S30

The ZWO Seestar S50 & Seestar S30 are fantastic tools for everyone, from complete beginners to experienced astrophotographers. They’re small, easy to use, and fun to share with family and friends. Until now, though, these smart telescopes have mainly been for casual sky watching rather than serious deep-sky imaging. But in April 2025, ZWO released an exciting update (Seestar app version 2.40) that adds equatorial (EQ) mode! With a bit of extra gear and a quick alignment, the Seestar can now capture longer exposures over longer periods, just like a full-size telescope setup!

What you’ll learn:

  • A review of EQ mode and why it's excellent for astrophotography
  • How EQ mode compares to the Seestar’s standard Altitude-Azimuth (Alt-Az) configuration, in terms of both performance and setup
  • How to physically convert the Seestar from Alt-Az to EQ mode, including what hardware you’ll need
  • How to set up a finder scope, and how to do a rough (visual) polar alignment
  • How to do a polar alignment using the ZWO Seestar app (for iOS and Android)

Video Overview of Seestar EQ Mode

Advantages of EQ Mode on the ZWO Seestar Platform

The new EQ mode for the ZWO Seestar offers significant benefits for astrophotography over its standard Alt-Az mode. First is the elimination of field rotation, an unavoidable side effect when imaging with an alt-az configuration. In an alt-az setup, the mount only moves left to right and up and down to track objects. When taking long exposures or stacking images, this causes noticeable field rotation, which appears as darkened corners and uneven illumination at the edges of images (as seen below).


With EQ mode, the mount is aligned with Earth’s rotational axis. This means it can track stars in one fluid motion as they move across the night sky in an arc. The result is pinpoint stars throughout the entire frame and a fully illuminated field.


EQ mode also enables the collection of more data through longer individual exposures and longer stacks. Longer exposures mean the Seestar can capture more photons and resolve finer details. Being able to take photos over a longer period improves the signal-to-noise ratio, producing images with less noise and smoother backgrounds.

Getting Started with EQ Mode: Setup, Accessories & Alignment

What you’ll need

The ZWO Seestar S50 in EQ mode. It is attached at a 40-degree angle using the iOptron Alt-Azimuth Adjustable Base.

 

For best results, consider using a more stable tripod than the one included with the Seestar. We’d go with the ZWO TC40 carbon fiber tripod or Sky-Watcher Star Adventurer tripod. To help with alignment, consider an optical finder or laser pointer. 

How to Roughly Polar Align the Seestar

By aligning the Seestar mounts to Earth’s axis of rotation, you are allowing the mount to track the sky in a natural motion. In its original Alt-Az mode, the Seestar tracks an object through the night sky with a stair-step pattern of up/down and left/right movements. But when you do a proper polar alignment, the Seestar is now able to move through the sky in one smooth arc while tracking an object. This means no field rotation and long exposure times, which in turn means better details and less noise.

1.   Instead of connecting the Seestar to a tripod as usual, attach it to an EQ wedge (also known as a latitude base) to match your latitude’s angle with Earth’s rotational axis.
The ZWO Seestar S50 setup at a 40-degree angle in EQ mode using the iOptron Alt-Azimuth Adjustable Base.

 

2.   This wedge will serve as the connection point to the tripod, but there are a few things to be aware of at this stage of setting up the Seestar for EQ use:
a.   You will likely need a 3/8"-16 to 1/4"-20 thread adapter. Seestar telescopes are made for tripod attachment (3/8"-16 thread), whereas most dovetails and mounting plates use the more standard camera thread (1/4"-20).
 
The underside of a ZWO Seestar S50 showing the single 3/8-16 tripod thread with a 1/4-20 adapter installed to attach to a dovetail bar

 

b.   If you don’t have a wedge, a very sturdy ball head can work; however, it will make fine adjustments more difficult.
c.   The Seestar must be able to rotate at its point of attachment, which means the dovetail should not be mounted flush with the main body. This is best achieved with a small extension, such as Agena’s tripod leveling base, which lifts the body of the ZWO Seestar and provides clearance between the Seestar, wedge, and dovetail. Once this extension is installed, you need a short dovetail in the 3 to 5-inch range to secure the mount. 
3.   Attach a polar finder to aid polar alignment. While some users have opted to drill holes into their devices, a simple, adhesive-based attachment is preferable for a variety of reasons.
a.   One simple technique is to use a plastic straw and line it up exactly with the lines of the Seestar itself. The design of the Seestar makes it easy to attach this in a straight line along the body, and we found that this was further improved by shining a laser straight through the straw.
 
The ZWO Seestar S50 with a straw attached for assistance with initial polar alignment

 

b.   For a more stable solution, we recommend the Rigel Systems QuikFinder. This comes with an adhesive base, eliminating the need for any drilling.
c.   Alternatively, there are some apps such as “Polar Scope Align Pro” that allow for polar alignment without further tools. The Seestar app felt easier as it takes readings directly from the scope, but if you’re already familiar with one of these apps it should work fine too.
4.   Place the Seestar on a stable surface. Try to position the body so that it sits over the North-pointing tripod leg. There is no way to use a counterweight, and this orientation will help prevent balance and stability issues that come from the Seestar being off-center. 
5.   Position the Seestar so the power button is facing up and the lens is facing so that it would point at Polaris if it opened 180-degrees.
ZWO Seestar S50 in the proper orientation for equatorial imaging using an iOptron Adjustable Altazimuth Wedge.

 

6.    Do a rough polar alignment using your finder. It doesn’t matter if alignment isn’t perfect. You can fine-tune it using your Seestar’s built-in polar alignment routine. If this is your first time running the Seestar in EQ mode, then you may need to do your best and eyeball it. The Seestar polar alignment routine will get you there eventually, at which point you can lock in your finder for the next time using Polaris (or Sigma Octantis for all you Southern Hemisphere folks).
7.   You are now ready to power on the ZWO Seestar!

 

Accessing and Using EQ Mode in the ASIAIR App  

1.   Connect to the Seestar App: Pair the Seestar app with your Seestar S50 or Seestar S30 over Wi-Fi or Bluetooth. We used WiFi for all testing here.
2.   Enable EQ Mode: Select the mount by clicking on its ID, which is located just below the picture of the unit. Then scroll down to “Advanced Features”, select “Mount Mode”, and look to the top right corner of the screen for a “Switch” button.
3.   Enter the Polar Alignment Workflow: Once you have selected EQ Mode, simply follow the app's polar alignment routine. Making fine adjustments until the system verifies adequate alignment.
4.   Slew to Your Target: After aligning, you can select a celestial object by either searching for it under the “Stargazing” menu on the main screen, or you can look around using the included sky atlas and select your target from there. From there, the mount will auto-center the object and begin stacking exposures of your chosen length. Thanks to your polar alignment it will be able to track accurately in EQ mode and collect many hours of data!

Astrophotography Comparison Using EQ & Alt-Az Modes

Using the new EQ mode, we took images of Messier 101 and Messier 106. We used 30-second exposures for both targets. While imaging, the Seestar’s EQ mode maintained sharp stars for hours, and neither showed the slightest bit of field rotation. The only issue was a bit of a gradient that was likely because of the moon. This was easily removed during post-processing.

 

Messier 101

Seestar S50 in EQ mode

185 images x 30-seconds (~92 min)
IR Cut Filter
Bortle 5-6
April 5, 2025

(Processed in Pixinsight)

Seestar S50 in Alt-Az (standard) mode

553 images x 10 seconds (~226.5 min)
IR Cut Filter
Bortle 1-2
April 8, 2024

Messier 106

264 images x 30-second (132 min)
IR Cut Filter
Bortle 5-6
April 6, 2025

127 images x 30-second (~63 min)
IR Cut Filter
Bortle 5-6
April 6, 2025

 

By comparison, we used the Seestar’s classic Alt-Az mode to capture this image of Messier 101, under Bortle 1-2 skies. In Alt-Az mode, it is best to stick to 10-second exposures rather than 30-second exposures. Even with the shorter exposures, you can see that field rotation is clearly still producing major issues in the final image.

Our verdict on the Seestar EQ Mode:

ZWO has finally provided the software support needed to transform their Seestar platform into a legitimate imaging setup. And they’ve done so without sacrificing any of the usability or simplicity that has made the Seestar series such a game-changer for beginners. If you never want to use this feature, it can remain hidden away in the menus of the Seestar app, and if you ever want to go back to AZ mode, it’s only a few clicks away. But for Seestar users looking to take their astrophotography to the next level, this is a very easy adaptation that offers big results. If nothing else, we recommend you give it a shot.

Agena Astro is here to help! If you have questions or need a hand, contact us.