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PhotoGav

QSI Vertical Banding Issue

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And the 300 master bias (screenshot)...

image.png.548588dead2748a2ec2db57626829d5d.png

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Posted (edited)
9 minutes ago, Jonk said:

If this issue only happens in cold temperatures

The banding was apparent in mine at an ambient of around +5c and a sensor temperature of -15c. If it is there you will see the banding most clearly in calibrated darks so make a master bias as you have done, you won't easily see the banding in the bias, and use that to calibrate a master dark of at least 50 frames. The banding will then show clearly, if it exists, with your camera.

( my master dark image in the forum post showing the banding was 100 frames @ 300 seconds )

Edited by Oddsocks
Added text in brackets

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Indeed, the camera needs to go in the fridge overnight running 30 minute darks to make a master dark before I decide if there's an issue that a fw upgrade is required to fix.

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Well, I've put the camera into a freezer on the lowest setting, and with the camera on / cooler off, it was reporting -0.5 temperature after stabilising for around 3 hours, so I was happy to proceed.

I ran continuous 30 minute darks overnight (at -20 sensor temperature) but last night, I checked the 1st one before bed and the banding seems to be there, faint but noticeable when autostretched - and I know it's not an illusion, as I asked for a 2nd opinion and it was confirmed, as she didn't know what I could see beforehand.

I'll stack 50 or so darks later tonight and post the result, but I think I have the same issue and hopefully, all being well, the FW update will fix it.

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I've stopped at 46 x 1800s darks, calibrated with the 300 master bias, and stacked.

The freezer internal surface temperature was around -10 degC and the camera body surface temperature was around -2 degC.

Double screen stretched the resulting stack, saved as PNG, and here's the result.

I would say that's pretty conclusive?!

1492299487_Masterdark46-20.thumb.png.d4d227931a3f70c6c9ee046780ec2523.png

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I've followed the instructions (thanks @Oddsocks) and the camera has been updated successfully.

1993475406_Camerafpgaupdatedwithnoerrors.png.6d6153960037837489a30127529227b7.png  173605331_CameraFWupdatedwithnoerrors.png.bb6059233453e8a2aed3e0e22c57388e.png

I've put it back in the freezer at around -10 degC air temperature and will start a full run of 100 x 1800s -20 degC dark frames, followed by maybe 2000 bias frames.

This should show, after calibrating and stacking, that the banding has gone and give me a master bias and a master 1800s -20 degC dark to use for next season, should I manage to get any imaging done.

Thanks @PhotoGav for having the same issue and posting it, otherwise like Oddsocks and maybe others, I would have been none the wiser.

Cheers all.

  • Like 2

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Well done @Jonk, always slightly nerve racking when you hit ‘start’ on that update. I look forward to seeing the post update master dark as the pre update version is blatantly afflicted with the banding issue.

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Posted (edited)
39 minutes ago, PhotoGav said:

I look forward to seeing the post update master dark 

Funnily enough, so do I...!

It's running as we speak, 2500 bias followed by 150 darks so Monday evening I should be able to report back.

Edited by Jonk

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Sorry for the late repsonse...

Here's the result of the FW upgrade.

2508 bias to make a Master Bias.

150 x 1800s -20Deg C darks, calibrated and stacked to produce the Master Dark.

All this in a freezer that had roughly a -15 deg C internal surface temperature and -5 Deg C camera surface temperature (measured with an IR thermometer).

Image screen stretched and saved as PNG to share here.

I would say it's now sorted, wouldn't you?

1169398930_Masterdark1800s-20DegC.thumb.png.da27cc5fcbb832887b0871f68a306762.png

 

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Perfect result. Now you need some clear, dark skies... may be a while!

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A FW upgrade on the weather would be nice!

Agan, cheers for bringing this up, at least I won't have the issue when it finally comes to do some imaging. 👍🏻

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