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smr

band running along image

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I've just stacked 5 hours of subs from last night and did a linear stretch - I thought I could see this present in some of my subs at the time but I thought it was maybe a monitor / team viewer thing or something which stacking would get rid of if it was on the images.

What is it ? Aside from what looks like 5 hours of wasted subs. 😞

Exposure times were ISO 200 and 240 second subs. I took 30 flats and used 50 bias frames from another session, at the same ISO value.band.thumb.jpg.8cab81cf86e6e816090e6997952ef82f.jpg

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Have no idea but can see another blue band below it on my screen with the hint that there might be others too.

Alan

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5 minutes ago, happy-kat said:

Is the band on individual subs?

Yes

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One thing I can think of that I did differently this session was to download images to the laptop and not the card as well. Before this I've always downloaded to both, but I left the card in the camera even so.

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7 minutes ago, Alien 13 said:

Have no idea but can see another blue band below it on my screen with the hint that there might be others too.

Alan

Yup 😕

 

banding.thumb.jpg.aaef5559946a4e2f6d39c522ef589730.jpg

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4 minutes ago, smr said:

Yup 😕

 

banding.thumb.jpg.aaef5559946a4e2f6d39c522ef589730.jpg

That shows it better, I did wonder if my eyes were playing tricks. I hope someone comes along that has a solution..

Alan

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11 minutes ago, smr said:

One thing I can think of that I did differently this session was to download images to the laptop and not the card as well. Before this I've always downloaded to both, but I left the card in the camera even so.

I don't use a DSLR but this card-removal thing rings a bell. I think Carole wrote something about it. I've put a link to this thread on the cameras section.

Since the bands are colour-specific and the colours are read separately it might indeed have something to do with reading and saving.

Olly

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1 minute ago, ollypenrice said:

I don't use a DSLR but this card-removal thing rings a bell. I think Carole wrote something about it. I've put a link to this thread on the cameras section.

Since the bands are colour-specific and the colours are read separately it might indeed have something to do with reading and saving.

Olly

Thanks Olly.

We have clear skies forecast tonight so perhaps I should try removing the SD card.

I've never noticed this issue before since using a laptop, and this is the first time I have set for the images to download only to the laptop. But I left the SD card in the camera. 

This is also the first time I have gone longer than 2 minute exposures as well, to 4 minutes.

Edited by smr

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Just now, smr said:

Thanks Olly.

We have clear skies forecast tonight so perhaps I should try removing the SD card.

I'd certainly try that.

Olly

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I have always saved to the on-board card, is there a reason that you need to save it to PC instead?

Alan

P.S. Is the connection between camera and PC via cable or by using the camera wi-fi connection?

Edited by Alien 13

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I always save to card+PC and never experienced this.

Peter

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Same here, I've always saved to the PC. But one thing you need to check is that the USB port isn't slowing things down, e.g. same port for multiple devices. I've always used a dedicated USB2 port of the PC's etc. and have even at times, reduced download speed (If I get a chance later, I'll try & find the settings).

Also, what software are you using to control the camera, mount etc. ?  I usually use BackyardEOS, which can control everything'ish.

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Quote

I don't use a DSLR but this card-removal thing rings a bell. I think Carole wrote something about it.

I did indeed post something about taking the card out if downloading to the laptop (but I got that tip from some-one else in the first place).  However these lines don't look like the sort of lines I used to get with the card, they only really showed up when the image was stretched and much more diffuse.

But in the first instance is it worth trying.   Is it on flats and darks as well?

Carole 

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I've had this once when I stacked in DSS. I ran it all through Pixinsights pre processing and it almost removed the line. This was with DSLR as well and no dithering. Dithered ever since and not seen it again.

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You could download a free copy of AstroArt and try stacking in that. It won't save unless you buy the program but it would be a good test.

Olly

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2 hours ago, smr said:

What is it ? Aside from what looks like 5 hours of wasted subs. 😞

Exposure times were ISO 200 and 240 second subs. I took 30 flats and used 50 bias frames from another session, at the same ISO value.

Whatever causes it, it maybe possible to remove/reduce it with the CanonBandingReduction script in PixInsight. If you post the stacked, unprocessed image, I can have a look at it this weekend. 5 hrs is quite a lot of lost imaging time.

Edited by wimvb
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One more thing you can try is simply changing USB port. Sometimes I notice that with a certain USB it does it but with another not. Also I do the same thing with the SD card. 

You can also get rid of it in photoshop. Needs a fancy curve but works. 

Gerry 

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Firstly many thanks for all of your replies...

6 hours ago, Alien 13 said:

I have always saved to the on-board card, is there a reason that you need to save it to PC instead?

Alan

P.S. Is the connection between camera and PC via cable or by using the camera wi-fi connection?

No particular reason. I was watching a video of Trevor Jones' a while back and noticed on his laptop he had save to laptop and not card in APT, and I thought last night, well why am I saving to both if I only need to save it once. 

That said I've never seen this banding before, but aside from saving it to just the laptop for the first time there are two other factors which were different to my previous imaging sessions where this banding wasn't present... 1) 240 second exposures compared to max 120 (but I'd have thought that's not a reason as the only thing happening there, if I am correct in thinking this, is that the sensor is heating up perhaps  a bit more and there will be more hot pixels... and 2) dithering, I think, according to APT, that when a new light frames plan is selected and PHD2 is up and talking to APT that dithering happens automatically. The default values were left, but I can't see why dithering would cause this either.

6 hours ago, PeterCPC said:

I always save to card+PC and never experienced this.

Peter

I've never seen it before and all imaging sessions prior to this I have saved to card and PC too.

6 hours ago, Dr_Ju_ju said:

Same here, I've always saved to the PC. But one thing you need to check is that the USB port isn't slowing things down, e.g. same port for multiple devices. I've always used a dedicated USB2 port of the PC's etc. and have even at times, reduced download speed (If I get a chance later, I'll try & find the settings).

Also, what software are you using to control the camera, mount etc. ?  I usually use BackyardEOS, which can control everything'ish.

The USB connections on the laptop are USB 2, I have used this cable before quite a few sessions and I've never seen this banding.

5 hours ago, carastro said:

I did indeed post something about taking the card out if downloading to the laptop (but I got that tip from some-one else in the first place).  However these lines don't look like the sort of lines I used to get with the card, they only really showed up when the image was stretched and much more diffuse.

But in the first instance is it worth trying.   Is it on flats and darks as well?

Carole 

It's quite difficult to see it in the individual subs, but I think I can see it present itself as a very faint line. I can't really discern whether it's in the flats at all - it doesn't look like it though, I didn't take any darks or bias.

5 hours ago, david_taurus83 said:

I've had this once when I stacked in DSS. I ran it all through Pixinsights pre processing and it almost removed the line. This was with DSLR as well and no dithering. Dithered ever since and not seen it again.

I use APT and was using dithering last night for the first time.

4 hours ago, ollypenrice said:

You could download a free copy of AstroArt and try stacking in that. It won't save unless you buy the program but it would be a good test.

Olly

Will have a try, thanks.

4 hours ago, wimvb said:

Whatever causes it, it maybe possible to remove/reduce it with the CanonBandingReduction script in PixInsight. If you post the stacked, unprocessed image, I can have a look at it this weekend. 5 hrs is quite a lot of lost imaging time.

Ok thanks, I'm going to take some more images tonight, actually I was going to remove the card but now I think I'll keep the card in and have APT do what it did before ; save to both. If I still get banding then it must be either the long exposure or dithering as they are the only things different to any other session where the banding wasn't present.

3 hours ago, Gerry Casa Christiana said:

One more thing you can try is simply changing USB port. Sometimes I notice that with a certain USB it does it but with another not. Also I do the same thing with the SD card. 

You can also get rid of it in photoshop. Needs a fancy curve but works. 

Gerry 

Thanks, I'll try and make use of the subs as 5 hours is as has been said quite a lot of imaging time.

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Right, so I've just set up and started imaging, saving to laptop and card now. 

I've also just had a look at a single sub in LR from last night and done some quick editing on it to see if I could see the band - I can, so it's not a stacking problem...

1129462564_singlesubband.thumb.jpg.1df67bf19eaf87ac93e707f893e3afcd.jpg

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And here's a sub from tonight, I synchronized the edit on this sub... not sure why it looks different but could be the moon glow difference.... but I am struggling to see the same purple band ?  Can you see it on this one?

1518336220_tonightsub.thumb.jpg.417eaf015da2ca316a528ac253bba65e.jpg

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And another sub... I've made it as contrasty as I could to show any artifacts in the sub and can't see the bands... so I think it can be concluded that it was because the memory card was in the DSLR but it wasn't being written to ...

I'd love to understand the science behind that. I can't quite understand why you'd get a band just by not reading to the card as the computer / card / dslr has one less thing to do! But then I work in computers and fixing them so I'm not surprised! 

Must thank Carole for the heads up on this. I had done a search and found the post about it possibly being the memory card, but I wasn't sure if it was in this particular instance. It seems it is though.

 

I can see the usual dust motes (one on the left and one top near right) and a few others, not sure why they look so massive, should probably clean my sensor at some point but that's not something I like the idea of doing.2061840090_anothersub.thumb.jpg.37853c77def0c24fcd10821a059cb80a.jpg

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with regards to this banding. What's interesting is that I was stretching the data earlier and the bands are actually behind the galaxies! Not sure how that works. But they are. So it *may* be possible to fix in post somehow. Not that I know but I'd be interested in any techniques.

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I saw this mentioned on CN and one person cured his 5dmk3 by turning off the display grid.

Go in the menus and make sure the grid display is off in the red menu and the viewfinder display
is off in the yellow wrench menu.

I have no idea if this works but quite few people had this with 7dmk2's.
Never saw it in my 7dmk2 but then my display grids were both off.

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On 17/02/2019 at 15:57, wxsatuser said:

I saw this mentioned on CN and one person cured his 5dmk3 by turning off the display grid.

Go in the menus and make sure the grid display is off in the red menu and the viewfinder display
is off in the yellow wrench menu.

I have no idea if this works but quite few people had this with 7dmk2's.
Never saw it in my 7dmk2 but then my display grids were both off.

Thanks. Although i usually leave the grid display on after star alignment and havent had the problem with it before.

I stacked those images i took with the card being written to and the bands arent present in any of the subs or stacked image so it must have been that. Still dont understand why it does that if you dont write to the card though.

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