Clipped/noisy subs - Possible FITS pedestal/black-level regression

fzach

I want to share a reproducible issue I encountered with the Seestar S50 after updating to Seestar System version 26.1 and Software/App version 3.0.0.

After the update I noticed how my subframes captured with the Seestar changed and showed a very noisy pattern, see left for before and right image for after the update:

I tried to integrate these files with PixInsight but it already stalled/failed on the Debayer step with the error message:
No valid PSF signal samplex on channel ...

Also the Subframeselector could not load multiple subs at once so I made a script to meassure them with astropy to confirm my hypothesis that somehow the calibration on these files was off - not that I let it print Reject on corupt files:

Post-update frame has ₅₅% of all pixels pinned to the minimum value (0 after BZERO/BSCALE scaling). Given BZERO=32768, this corresponds to raw stored values saturating at the minimum possible signed 16-bit value (−32768) at extremely high frequency, which is consistent with excessive pedestal subtraction / black-level miscalibration / clipping introduced by firmware.

This kind of clipping systematically destroys faint stellar signal and PSF sampling, explaining why PixInsight cannot generate valid PSF signal samples during debayer/PSF detection.

Tested it on 3 different nights, different targets in good conditions with bortle 4. Problem seems to be more pronounced when i have the LP filter on I can also meassure a difference in SNR in IRCUT subs compared to subs before the update :/

Unfortunately I have already seen many reports on social media for this and I already made a bug report on 12/19 on this. I think this is a real issue as it destroys the data and already made me lose 3 imaging nights because of this error.

I made this post so other users can find the issue and see that they are not alone.

Thank you for looking into this ZWO.

Support@Seestar

fzach This seems to be a dark field issue. Could you upload the logs so we can take a look?

wVU1j6V6

Same here with S30. RAW calibrated fits from the scope, autostreched, no additional processing, 10 seconds exposure:
1) Prior to update:

2) After the update:

Severe noise issues after the update. I saw people reporting this when LP filter is used, as in my pictures above. Seems like 3.0.0 broke something with in-scope dark calibration. All frames come out like this now.

Flipside

Has anyone found a fix for this yet? I have the same problem. Tried basically everything besides a full reset.

6gYT4MFO

Flipside there is no full reset, you can only reset the WiFi...

6gYT4MFO

Is this the same problem? Both pictures stacked out of the seestar s30. The brighter one before the Update, the darker one thereafter.
Is it wasted time to collect some pictures with that error?

wVU1j6V6

6gYT4MFO Yes. Since 3.0.0 all data can be thrown out in a trash. Seestar clips useful data from images. I don't get why would they do that at all, it's an obvious bug and should be adressed immediately. It basically completely ruined our scopes.

6gYT4MFO

wVU1j6V6 Thank you for the answer. So its useless to get outside and collect some light...annoying 😞

davidf

Yes, just to confirm that this is a disastrous update for image quality. I won't be using my S50 until it is fixed. I have already wasted many hours of my, very limited, imaging time.

6gYT4MFO

davidf hopefully get a fix soon...

Glabella

Hello Support@Seestar …. Can this be acknowledged one way or another please.

Seestar_S50

No point in ordering the S30 Pro, might as well use a pin hole camera to capture DSO's! Very disappointed in the latest update, one step forward and two step back, obviously there is no testing of the updates before they are released. This major issue surly would have been discovered if someone at ZWO had bothered to turn on their Seestar and take a few frames.

zjW8Hx8Y

+1
ZWO MOVE !!!

braunschweiger

And I thought I was the only one with this problem.

It's a shame it turned out this way, but hopefully ZWO will fix it soon, along with a few other minor issues.

Until then, the S50 is practically unusable for me because it only produces bad photos... :-(

6gYT4MFO

Did anyone contact the Support directly?

Nasa-HSIA

I've seen many people report this problem, and some images sent to me by others show inconsistent image contrast. These results indicate that this is already a widespread issue. I hope that ZWO can fix issue ASAF.

6gYT4MFO

Support@Seestar This Problem occurs by all these people after the new update, so its safe a bug with the Update.
Our scopes are literally unusable...
What do you mean with Dark field issue?

davidf

6gYT4MFO

Support@Seestar

Don't have the log to hand. Look at the attached light frame using your fits viewer and open the histogram view and expand. Blacks are massively clipped on every light frame taken since 3.0.0. Please fix

wvreeven

Has anyone tried taking new darks after updating to v3.0.0? If you did, did it solve the issue?

EDIT: I see v3.0.1 is available now. Support@Seestar is that supposed to fix this issue? I see there are "bug fixes" for which, unfortunately as usual, there is no further explanation.

fzach

Support@Seestar

I have made a bug report on December 19 and shared all the fits I have via Google Drive link.

Bug report it no BT20251220106027S

I made this post to see if everyone else had such issues and in fact they do.

I successfully run my Seestar with Nina atm- love the firmware updates for this part but I lost a lot of subs that I shot with the Seestar app before I noticed.

BiF

After updating the app, I have the same problem as others: higher noise, inconsistent contrast.

Another problem after the update: I can't use 60s exposure, 90% of the images are "unguided." Before the update, I had less than 5% bad images with 60s exposure!!!

@ Support@Seestar: Please immediately resolve all issues caused by the software update reported here and elsewhere, or temporarily allow the previous version of the software to be installed. Otherwise, the Seestar S50 is currently unusable!!!!!!

I pre-ordered the Seestar S30 Pro, but now I have canceled my order!!!
Please resolve everything!!!

davidf

Cant seem to upload the file. You should be able to look at any light frame taken since 3.0.0 to see the problem. Large amount of data being clipped.