Disappointed by ZWO's quality standards

Balrog

After a few days of using my Seestar S50, I noticed that my telescope had miscollimated lenses, in the upper right corner the coma of the stars was really accentuated, after consulting with the store where I bought the telescope, they told me that they would consult with the European supplier since it was evident that it had a miscollimation of the lenses, the response from the supplier in Europe of ZWO, that according to the images that I show here, my Seestar S50 meets the quality standards.

This is the last time I buy a product from ZWO, and I warn those who want to buy this product, what quality of service they will get.

All photos are a single 10 second shot, there is no stacked shots.

This is the same star positioned in each corner:

Sonixx

You will always experience quality variations on a product that meets the set quality standard. While what you see is not perfect, but not too bad for a €700 includes it all plastic scope.

You have to spend way more if you want to go next level, but problems with bad stars in corners still commonly exist. And kit gets much larger.

Other things to consider:
-after stacking things normally look better
-use BXT or other software to correct star images

If it is still in return policy period, send it back and get a refund, in case you can‘t live with it.

Regards,

Stephan

Balrog

Sonixx

You will always experience quality variations on a product that meets the set quality standard. While what you see is not perfect, but not too bad for a €700 includes it all plastic scope.

Ok, I agree with that, except that other telescopes usually allow you to adjust the collimation, which is not the case with the S50, and 700€ is a considerable amount to demand a minimum of quality. It is not the first telescope I have had, my Meade ETX 80, despite being achromatic, does not show aberrations of this type and is half as cheap. It is true that it does not have an LP filter or autofocus, but at least the optics meet a minimum of quality.

You have to spend way more if you want to go next level, but problems with bad stars in corners still commonly exist. And kit gets much larger.

I have a larger Newtonian telescope, and HEQ5 mount, guide scope,... I bought the Seestar S50 so I could do more astrophotography, and honestly, of all my telescopes, this one has the worst collimation problem, and it cannot be collimated.

If it is still in return policy period, send it back and get a refund, in case you can‘t live with it.

Yes, I'm working on that with the store, I hope I can return it.

And thanks for sharing your point of view.

Gulyas K

This is not miscollimation, but sensor tilt. A stepping motor is adjusting the sensor, this is how Seestar is focusing. If something is too tight, or too loose inside, this could cause sensor tilt. You can see the mechanism on the lower right part of the photo.

Mine had the same issue. I brought it back to the seller, showed them a sensor tilt measure photo from Siril and they gave me another Seestar immediately.

The new one has absolutely no sensor tilt, stars are pinpoint sharp in all corners.
Sometimes it helps if you switch to manual focusing mode in the app and adjust the focus all way through between the two extreme ends for a few times. As I remember well, 0-2600. Do it 4-5 times and you'll see. Some users said that this solved their sensor tilt problem. Not mine, this is why I brought mine back to the seller.
In your case, you did not experience this issue immediately, just a few day later, so I guess this will work for you too.
Anyway, if you take a closer look at other users' photos on FB, or in Seestar forums, a lot of them have this issue. Always in the upper right corner.

Balrog

Gulyas K

Sometimes it helps if you switch to manual focusing mode in the app and adjust the focus all way through between the two extreme ends for a few times. As I remember well, 0-2600. Do it 4-5 times and you'll see. Some users said that this solved their sensor tilt problem. Not mine, this is why I brought mine back to the seller.

Unfortunately, this hasn't worked with my Seestar, although it seems to have leveled out a bit vertically, with the top right and bottom right now being similar, but there's still a horizontal tilt. And seeing the store's requirements for returning a product (I'd have to file a claim with the consumer office, and might not get all my money back), I think I'll keep this unit despite the optical defect.

Thank you very much for the information, at least I have been able to improve a little the optical defect caused by my Seestar, even though there is still a horizontal tilt.

Brille

In fact, I also have this distortion in the top right of my S50 - until now I had assumed that I would have to live with such inaccuracies in this price range. I probably can't exchange the Seestar after 5 months, I'll ask my dealer. Before that, I'll try the multiple manual focus settings over the entire range.

Brille

I've applied Siril's tilt command to a whole series of photos from one session and I'm a little unsure. Each image produces different results, sometimes strongly and in different directions distorted trapezoids, sometimes relatively even squares and often directly one after the other. Can the sensor be so loose that it tilts back and forth that much?

Gulyas K

Brille I experienced exactly the same. Actually I have no clue if something is too tight, or too loose in your system, but this is obviously an issue. And we have to remember, that star trails and guide issues can cause fake tilt results sometimes. Try to apply the tilt command on a photo stacked by Siril. If it's square, then all is good. I bet it will not be square....
As I mentioned, I experienced the same. The new Seestar given by the seller has no tilt issues at all. I've also applied Siril's tilt command to a whole series of photos shot by this new Seestar and the results are a sightly different on each photos, but the stacked photos are perfect!
Let me show two examples. The first was shot by the problematic Seestar, the second by the new one.

Gulyas K

Balrog I guess You did not make a bad decision. Due to the field rotation, the edges of the photos must be cut off. So the defect mostly disappears if you don't keep the full field of view. Crop the images and all will be fine.