Bad optics in Seestar S30

thomas.westerhoff

I recently purchased a Seestar S30 directly from ZWO, not through a middleman. However, I have noticed that, especially when using the IRCUT filter, the stars are stretched out significantly in the lower part of the image. This also happens with the LP filter, but not as severely. What is the reason for this? In fact, you have to cut away a good third of the lower part of the image because the data in that area is unusable. I realize that a device of this price cannot deliver high-quality images, but even my cheap $70 telescope doesn't have such a severe optical flaw.

Balrog

The problem isn't exactly the quality of the S30's optics. The problem is the size of the camera sensor, which, combined with the lenses used, causes comatic aberration to appear. This problem could be seen in the first S30 images published in the Seestar app community. If the star distortion is only on one edge of the image, you could also have a tilt issue with the sensor. My first S50 had a lot of tilt, and only the store where I bought it accepted that it was a problematic unit and replaced it with another one with almost no tilt. Zwo's European distributor didn't accept that there was any problem. Returning to the S30, I bought it knowing about the comatic aberration issue, as I find it to be a much better portable device.