Seestar S50 Review

The SeeStar S50 is an all-in-one smart telescope that makes astrophotography easy. While its main goal is to deliver electronically assisted views of objects in space, the pictures it takes are pretty darn good.

If you thought that smart telescopes were just “expensive toys”, I think you’d be surprised to see some of the incredible deep-sky images being captured with this device. You can watch my Seestar S50 Review video review, below. 

While this little telescope package is not exactly high-end in terms of photography performance, it does an admirable job with what it’s working with. The Seestar lets anyone take their own astrophotos without any previous photography experience.

It does all of the difficult parts of the astrophotography experience for you. You don’t have to worry about polar alignment, finding objects, or focusing the camera. You just pick the object you want to see, it off it goes. 

With a current price of $499 USD, the Seestar S50 is one of the cheapest, fastest, and easiest ways to get an impressive photo of the Moon, the Sun, and deep-sky objects such as galaxies and nebulae. 

If finding and capturing pictures of objects in space isn’t enough, it calibrates and stacks the image data internally too. This means you have an impressive, stacked, and stretched image ready to share within minutes. 

In this article, I will share everything you need to know about the mighty Seestar S50 all-in-one telescope including its biggest strengths and weaknesses. 

The Seestar is available for $499 (USD) at Agena Astro.

Seestar S50 Review

While the debate continues as to whether or not images captured by the Seestar are considered to be ‘astrophotography’ by its traditional measure, you can’t argue with the fact that the Seestar delivers results.

I must admit, that it doesn’t feel like I really did anything when I captured the images on this page. Unless you count placing the device on the ground and pressing a few buttons on the mobile app. 

However, the same could be said about highly automated astrophotography setups and personal observatories. I think the point is, that everyone has their own preferred level of interaction with their equipment when taking photos. 

The Seestar S50 is great for exploring, outreach, and enjoying astronomy with your friends and family. It is not meant for serious deep-sky astrophotography projects that you intend to submit to competitions or print in large format. 

The Horsehead Nebula by Brian Fulda. Seestar S50. Stacked in AstroPixelProcessor and processed in Photoshop.

Who the Seestar S50 is for:

• Beginners looking to photograph the Moon, Sun, and Deep-Sky Objects
• People who want an easy way to locate and view objects in the night sky using EAA
• People interested in astronomy, that don’t have the time or resources to dive into astrophotography
• People interested in facilitating astronomy outreach and education

Who it is NOT for:

• People who want to take detailed close-ups of planets and dim deep-sky objects
• Experienced astrophotographers who already have sophisticated camera and telescope systems
• People who want to construct a custom imaging setup catered to their specific needs
• People looking to capture and print large, high-resolution astrophotography images 

The Sun and Moon captured using the Seestar S50 smart telescope. Slight edits in Adobe Photoshop to the original images.

What’s Inside the Seestar S50?

Inside the Seestar unit is a 50mm triplet apochromatic refractor telescope, a dedicated astronomy camera, a light pollution filter, a built-in dew heater, and a tracking GoTo mount. Yes, it’s an alt-az mount, but it works. 

The internal light pollution filter, which I am told is a duo-band filter (similar to the L-eNhance), can be turned off and on depending on the project. By default, the light pollution filter will be automatically applied when you capture most nebulae in the night sky.

The addition of this light pollution filter makes the unit a lot more suitable for astrophotography in the city (I live in a Bortle 6). If you want to capture a more natural-looking image or a broadband subject like a galaxy or star cluster, you can turn it off. 

I was also thrilled to see that the telescope also includes an integrated dew heater and that it’s rated to operate down to -10°C (14°F). This simple addition is the difference between a full night of imaging and packing up from my location.

Camera and Telescope Specifications

The Telescope

The 50mm triplet apochromatic refractor telescope inside the Seestar has a focal length of 250mm and a focal ratio of f/5. Normally a 250mm field of view covers a large area of sky, but in combination with the small camera sensor on the Seestar, it is actually quite narrow. 

It is interesting to compare this to a stand-alone triplet apochromatic refractor telescope. I couldn’t help but compare the telescope in the Seestar S50 with a William Optics RedCat 51, a 51mm aperture APO with a focal length of 250mm.

Even though the RedCat 51 (A Petzval design) is superior optically, it costs much more than the price of the entire Seestar package. My point is, that the amount of value in the Seestar starts to add up when you break down each of the components. 

The Camera

The one-shot-color astronomy camera inside of the unit uses the same CMOS sensor found in the ZWO ASI462MC. This camera captures images and videos that are 1936 x 1096 pixels in size, which equates to about 2 megapixels in total. 

Due to the sensor’s shape and size, it creates images in a long, vertical format, about the same size and resolution as a typical phone screen. While this aspect ratio may take some getting used, the format lends itself well to sharing and viewing images on social media.

In my opinion, one of the biggest limiting factors of the Seestar is its narrow field of view. This is especially apparent when capturing large objects like the Andromeda Galaxy. With an imaging window of about 1 degree, you will only be able to capture a section of the galaxy at once. 

The Andromeda Galaxy being captured by the Seestar S50.

The Tracking Mount

The Seestar S50 uses an altitude azimuth (alt-az) style mount to move the telescope around and track objects in the night sky. While typically an equatorial telescope mount is needed for long-exposure astrophotography, an alt-az mount like this can still be used as long as shorter exposure times are used. 

You do not need to polar align (or ‘star align’ the mount on the Seestar S50 to start taking pictures. The mount uses plate solving to automatically understand where it is pointed in the night sky.

As long as the tripod and mount are level, you have allowed the GPS setting, and it is dark enough to capture stars in the sky, the Seestar will understand where it is pointed. 

Seestar S50 Specs:

• Mount Type: Alt-Az
• Sensor: IMX462
• Resolution: 1096 x 1936 pixels
• Aperture: 50mm
• Focal Ratio: f/5
• Focal Length: 250mm
• Optical Lens: Apochromatic Triplet
• Net Weight: 2.5kg
• Storage: 64 GB 
• Transition mode: Bluetooth 5.0, WiFi 5G, 2.4G
• WiFi Range: 15 Feet
• Working Temperature: 0 – 40°C (32 – 104°F)
• Power Input: USB Type-C
• Slew Rate: 1X – 1440X
• Zero Position: Mechanical
• Battery Capacity: 6000mAh

What’s Included in the Box?

The Seestar S50 weighs 6.6 pounds (3 kg), and it comes in an impressive, compact foam carry case. Everything fits neatly inside the protective foam case, including the small carbon fiber tripod.

The little tripod includes 3/8″ threads and can be extended to a maximum height of 363mm. A quality, collapsible, lightweight carbon fiber tripod like this adds even more value to the package. 

You can also thread the Seestar S50 to a larger tripod, as long as it has the 3/8″ thread size to attach the unit. 

• Seestar S50 Telescope Unit
• Mini Carbon-Fiber Tripod (3/8″ thread)
• USB-A to USB-C Charging Cable
• 580-630 nm Solar Filter
• Quick Start Guide

The foam storage case fits all of the components tightly and secure. 

Because there is no hand controller or way to operate the unit directly, you need to download the Seestar mobile app and connect to the device using a WiFi connection. 

Seestar Mobile App & Sky Atlas

To control the Seestar S50 and download your images, you will have to download the dedicated Seestar app for your Android or Apple device. The Seestar app features a star map (Sky Atlas) with an extensive database of celestial objects including a ‘tonight’s best’ list. 

After allowing your location settings, you will see some helpful astronomy weather information, including the current moon phase, and moon and sunset/rise. You will also have the option to select your primary observation mode:

Stargazing Mode

The stargazing mode is where most users will spend the majority of their time. This mode is where you can see a live view of the night sky wherever the Seestar is pointed, and is where you go to start taking and stacking deep-sky images. 

The telescope automatically plate solves the image to determine the layout of the night sky based on your location and provides recommended targets for you to capture. You can press the record (capture) button to start collecting and stacking images and you will see your image on the screen get better and better.

Solar Mode

With the included solar filter in place, you can use the Seestar S50 to capture detailed views, images, and video of the Sun, including sunspots. I initially ran into some trouble with the Seestar not being able to find the Sun on its own.

After manually pointing the Seestar in the general direction of the Sun, it managed to find it and center it on its own. Finding the Sun with a solar telescope with such a narrow field of view can be tricky. 

Using the Seestar S50 in ‘Solar Mode’ with the solar filter in front of the lens. 

Lunar Mode

The Seestar S50 can take fantastic images and videos of the Moon. For the best possible results, you will want to capture video files in .AVI file format and use a planetary image stacking software to select and stack the best frames. 

The focal length of the telescope and the CMOS sensor used are well-suited for lunar photography. This is one of the primary ways I will be using the Seestar S50 in the backyard. 

Scenery Mode

This mode is used for daytime photography and video of terrestrial objects, such as wildlife or landscapes. While this feature is likely not why most people will buy the Seestar, I think you will be surprised at how fun it is to use.

Having precise control over a lens at a focal length of 250mm (faith autofocusing) is a lot of fun. I look forward to watching the bird feeder in our backyard using the Seestar in scenery mode. 

Seestar S50 Setup

Once fully charged with the USB type-C cable, it lists a battery life of up to 6 hours. With the tripod base and the telescope taken out of the box, securely connect the tripod to the unit and ensure the tripod is level to ensure the Seestar S50 will work correctly.

With it being so light and short, you’ll also want to be careful not to knock it over on the pavement. 

To get started:

• Activate: press the power button for 2 seconds, the voice prompt will let you know once it’s powered on, tap connect
• Connect: select the device you are connecting to and follow the prompts to complete the connection
• Open App: after connecting the app will connect to the internet and active the device
• Connect to WiFi: select the unit you want to connect from the wifi connection screen. The listed WiFi range is 5 meters and from that distance, the connection has been very stable for me.
• Observation mode: choose your observation mode from stargazing, solar, lunar, or scenery.

If you want to take images, select stargazing mode and continue: 

• Stargazing mode: choose your target and the telescope will automatically point to it.
• Light pollution filter: if you are imaging from the city, it is recommended that you turn on the light pollution filter
• Anti-dew: if you are in a humid climate where dew on the telescope might be a problem, turn on the anti-dew function.
• Autofocus: tap the screen to activate autofocus
• Select target: select and mark your target and complete a brightness adjustment

Astrophotography with the Seestar S50

Using the stargazing mode, you can take images of deep-sky objects, using the same techniques astrophotographers use to create deep images. The Seestar will automatically take and apply dark frames to your image, which is an important calibration step to improve the final image. 

For example, if you’ve selected the Orion Nebula as your target choice, the camera will continuously capture and stack 10-second images, and the picture will get better and better. After about 10 minutes of imaging, you should see a major improvement of the nebula on the screen. 

Some people will enjoy using the Seestar S50 simply for EAA, or electronically assisted astronomy. This involves pointing the telescope at various targets in the night sky and enjoying the near real-time view of the object through photography. 

The Orion Nebula using the Seestar S50. Slight edits in Adobe Photoshop to the original stacked image. 

For those who want more control over the final image, you can also save the individual sub-frames to stack and process yourself. YouTube Cuiv the Lazy Geek did an interesting experiment where he stacked 5 hours’ worth of exposure time to create an impressive image of the Pacman Nebula. 

In solar and lunar observation modes, you can record videos in MP4 and AVI format, and process those using a planetary image stacking tool like Autostakkert or Registax. This process involves selecting a percentage of the best image frames captured, to create a sharper overall image of the Moon or Sun.

Accessing Seestar Images on Your Computer

To access and save the deep-sky images you have taken on the Seestar on your computer, you need to power on the seestar and connect it to your PC with the USB cable.

As long as the Seestar is powered on, your computer should recognize the storage device as a new drive on your computer. Look for the ‘MyWorks folder’, as this is where the image files are stored. 

Here, you will see all of your projects in their own folders, named after the object you photographed. All projects are found here, from deep-sky nebulae to planets. The file you want to process is the stacked FIT file, not the tiny JPG preview file.

If you took videos of the moon or sun, you’ll see the AVI files here as well. I have not yet explored the option of saving the individual sub-frame exposures to stack myself. So, the image processing starts with stacked, calibrated master file to bring into your favorite image processing software such as PixInsight or Adobe Photoshop.  

Keep in mind, to edit the photo using Adobe Photoshop, you will first need to convert the .FIT file format to a TIF file first. This can easily be done using a free tool like DeepSkyStacker. 

The Pelican Nebula in Cygnus by X User capnrob9756. Seestar S50 (stacking and processing using only the Seestar S50)

Helpful Seestar S50 Accessories

Since the product was announced, several third-party accessories have been produced to help maximize the potential of the Seestar S50  Some of these items include 3D-printed Bahtinov masks, and dust covers for the telescope lens. 

I found the autofocus feature on the Seestar to work exceptionally well, but others insist that a Bahntiov focusing mask is needed for precise focus. For a price of $10, I think it’s a no-brainer for those who want to verify that the telescope has achieved critical focus. 

Others have mentioned that the use of a camera leveler with a 3/8″ thread is helpful to ensure that the Seestar S50 is perfectly level when in use. While I love the compact carbon fiber tripod that is included with the Seestar, it is very short, and some people have decided to upgrade to a taller model.

Limitations

While there is lots to praise about the Seestar S50, here are some of the limitations to consider:

• Given the size of the sensor, the images are pretty small and the field of view will limit your projects. Also, the vertical image format might take some getting used to.
• If you’re using the Seestar S50 to explore the night sky and share photos, the image size is perfectly fine. For serious astrophotography projects that you can print, you may want to stick to your dedicated astrophotography rig.
• The 50mm aperture isn’t big enough to capture detailed images of super dim objects, and planets are really small at 250mm.
• The alt-az base is not equatorial. This means field rotation in anything over 30 seconds or even sooner, and you’ll need to work around this. That means no 5 minutes subs on this device.

Keep in mind, that this is an entry-level device designed for beginners. For the size and price, there is a lot of value here. 

While the small sensor and Alt-Az base limit the Seestar S50’s capabilities, it makes up for these shortcomings with thoughtful strategies (like live-stacking and automatic frame rejection) to deliver the maximum potential of the unit. 

Conclusion

If you already have an astrophotography kit with a nice telescope and EQ tracking mount, you can probably take better pictures than the Seestar S50.

Your astronomy camera alone probably costs twice, if not three times the price of this entire package. But that’s not what the Seestar is all about.

It’s about allowing ANYONE to capture objects in the night sky, without knowing what dithering or field rotation means. It’s about plunking the Seestar on the ground and tapping a few buttons to see a live view of the Orion Nebula or Andromeda Galaxy.

Whether you’re live stacking a nebula to share it with friends and family, or you’re going deep on a photography project that you’ll process carefully when it’s done, the Seestar S50 delivers the best parts of astrophotography in a fun and easy way.

These are two words that are not often paired together, but I think the Seestar S50 may have finally pulled it off. To stay up to date with my latest astrophotography adventures, you can follow me on Instagram, Facebook, and X.

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Trevor Jones is a deep-sky astrophotographer and a valued member of the RASC. His passion is to inspire others to start their astrophotography journey on his YouTube Channel, so they can appreciate the night sky as much as he does. His images have been featured in astronomy books, and online publications including the NASA Astronomy Picture of the Day (APOD).

Helpful Resources

• Image Stacking Software for Astrophotography: Top Choices
• How to Choose an Astrophotography Camera in 2023
• The Best Astrophotography Telescopes Available (Tested with Examples)