My name is Masaya Henda (@achi-shanghai). I work as a technical manager in the automotive industry and currently live in Shanghai, China. Despite the strong light pollution of the urban environment, I enjoy astronomical observation and astrophotography. I currently own and actively use all three Seestar models.

Unfortunately, the total lunar eclipse on March 3 could not be observed due to unfavorable weather conditions. Instead, I have attached images of the total lunar eclipse captured in September last year.

When purchasing a smart telescope for the first time, I often see the question:

“Which should I choose — S30, S30 Pro, or S50?”

After using and comparing all three models myself, their respective strengths and ideal use cases have become very clear.

In this article, I will summarize the characteristics and differences of each model based on my real-world experience, specifically under heavy urban light pollution conditions. All comparisons shown here are based on actual images taken in Shanghai under Bortle 8–9 skies.

FOV Comparison of the Three Models: Orion Nebula (M42)

To clearly demonstrate the differences in field of view (FOV), I captured the Orion Nebula (M42) with all three models on the same night, at the same location, and under nearly identical conditions.

 

Exposure: 10 seconds × approximately 10 minutes; Original framing with no cropping.

• Seestar S50: The S50 has the narrowest field of view, and the core of M42 appears large and prominent. The Running Man Nebula and surrounding extended regions do not fit within the frame.
• Seestar S30: The S30 has approximately three times the field of view of the S50. Both M42 and the Running Man Nebula fit comfortably within the frame. Its wider framing flexibility makes it well suited for large nebulae.
• Seestar S30 Pro: The S30 Pro offers an extremely wide field of view — about four times that of the S30 and eleven times that of the S50. It captures not only the Orion Nebula but also the surrounding star field in a single frame.

At this point, the differences in "how much sky fits into the frame" should be clear.

S50: Highest Resolution Feel and Narrowest Field

Thanks to its larger aperture, the S50 has a clear advantage in fine detail compared to the S30 series. When images are compared at the same final display size, the S50 has a higher effective sampling density, resulting in superior detail reproduction in the central region.

If image quality is your absolute priority, the S50 remains the strongest choice. However, due to its narrow field of view, large nebulae require mosaic imaging. While mosaic mode compensates for this limitation, total imaging time increases significantly.

S30 vs. S30 Pro: Differences in Appearance and Common Misunderstandings. When viewing S30 Pro images, the Orion Nebula may appear very small. This is not due to lower image quality — it is simply because the field of view is much wider.

The S30 Pro’s field area is about four times larger than that of the S30. At the same time, the image resolution is also four times higher:

S30: 1080 × 1920

S30 Pro: 2160 × 3840

The important point is that the pixel scale (field of view per pixel) is nearly identical between the two.

Each pixel captures almost the same area of sky in both models.

In other words, the S30 Pro simply captures a wider area — its fine detail performance is essentially equivalent to the S30. The S30 Pro includes all standard S30 features with nothing removed. Functionally, it can be considered an upper-tier model.

Optically, however, there are structural differences.

The S30 uses a 3-element APO triplet design, while the S30 Pro employs a 4-element APO quadruplet.

Based on published specifications, the significantly expanded field of view likely required additional correction for off-axis aberrations (coma, astigmatism, field curvature, etc.), which may explain the transition to a four-element design. The slight increase in focal length from 150mm to 160mm also appears to be part of this optical optimization.

Even so, central star quality and detail rendering remain very similar. In practical imaging, the most noticeable difference is simply the wider field coverage.

It is also impressive that despite adopting a wide-field 4-element optical design, the S30 Pro remains relatively affordable. Four-element APO systems are generally more expensive to produce.

Additionally, the S30 Pro appears to feature significant internal hardware updates, including noticeably faster startup time (roughly twice as fast in my experience) and doubled storage capacity.

ZWO has successfully optimized mass production and manufacturing efficiency for smart telescopes, achieving wide-field performance and strong aberration correction without dramatically increasing cost. I was genuinely impressed by the level of optical engineering and product development.

AI DeNoise Processing Time Differences

During the Orion session, I noticed clear differences in AI DeNoise processing time:

S50 / S30: approximately 15 seconds

S30 Pro: over 60 seconds

With four times the pixel count, processing time increased proportionally.

For public outreach events where multiple targets are captured in quick succession, waiting over 60 seconds may feel somewhat long. It would be helpful if a reduced-area processing option (such as 0.5× framing) were available.

In reality, there are relatively few targets that truly require the extremely wide FOV of the S30 Pro. In many cases, mosaic imaging with the S30 may be sufficient.

S30 Pro Exclusive Features: Milky Way Mode and Star Trail Mode

The S30 Pro’s wide-angle lens shows its true strength in Milky Way Mode and Star Trail Mode. The field of view is wide enough to capture the entire Orion constellation in a single frame, making it ideal for wide-field star photography. However, in a heavily light-polluted city like Shanghai, the effectiveness of this mode is quite limited.

Milky Way Mode capturing the entire Orion constellation

To capture the Milky Way beautifully, dark skies with low Bortle ratings are essential. Depending on your environment, results may vary significantly.

Which Model Should You Choose?

Choose the S50

If you have darker skies, an open horizon, and sufficient imaging time.

For the same framing, the S50 delivers the highest image quality.

Choose the S30

Image quality is nearly identical to the Pro.

If you do not need wide-angle constellation photography and do not mind using mosaic mode, the more affordable S30 is an excellent option.

If you already own an S30 and are satisfied, the upgrade benefits of the Pro may be limited.

It is highly portable and convenient for travel.

Choose the S30 Pro

Ideal for challenging environments or limited imaging time. In heavily light-polluted areas, capturing a wide field quickly is important. In cities, buildings often restrict how long a target remains visible. With its wide field, the S30 Pro allows you to capture more data before the target disappears behind obstacles.

(However, Milky Way Mode is less effective in urban environments.)

Portability remains similar to the S30.

Conclusion

S50: Best image quality. Ideal for dark skies and long sessions.

S30: Same core image quality as the Pro at a lower cost.

S30 Pro: Best suited for light-polluted areas, limited sky visibility, and short imaging windows.

The "best choice" depends heavily on your specific observing environment.

In my case, I select based on the target:

For the Moon, the Sun, and smaller objects where detail matters — S50.

For framing both the Orion Nebula and the Horsehead Nebula together — S30 Pro.

For mid-sized regions like the Pleiades — S30.

I hope this information helps you find the model that best fits your needs. Thank you very much for reading.

Finally, I would like to share a sample image demonstrating the wide-field capability of the S30 Pro. Clear Skies!

Seestar S30 Pro

Mosaic imaging (10 seconds × 43 minutes)

Orion Nebula and Horsehead Nebula captured within the same field of view, All image processing performed using the Seestar app.

Photos and review by Masaya Henda (@achi-shanghai), Shanghai, China. All images were taken under Bortle 8–9 urban skies.