Is my camera on its way out??

[Skipper Billy]

In one of the two images I have produced so far this season I have noticed these horrible vertical lines as shown in the attached two images.

Red and green were taken before the meridian and appeared at the top left of the image and the blue was taken after the meridian and appeared bottom right of the image.

Given that the colour of the lines matches the filters I am thinking its a camera problem.

Its a 5 year old  Atik 16200 mono CCD and a full set of bias, flats and darks were used to calibrate the image although they are 'library' calibration frames and were taken about a year ago.

Maybe a new set of calibration frames would cure it or maybe my camera is on its way out???

Any pointers or suggestions most welcome!

(I have deliberately overstretched the images to make it easier to see the lines)

[Skipper Billy]

PS - I have just checked the other image I have made and the lines are in that one too but very much fainter - the only difference is the photos above were just 120 seconds - the other image is a narrowband image and the subs were 600 seconds and the lines are barely percetible. Not sure if that helps??

[Laurin Dave]

Looks like a dead column or two David..  easy to fix in Pixinsight using the linear Defect List option in Cosmetic Correction ...  so if you have Pixinsight ...open a raw sub open Cosmetic Correction and click on Defect List, click on the bad column and it should be recognised..  Then run CC ...  if doing WBPP set up CC as a template before hand and apply it in WBPP..   Also works well for correcting this sensors hot pixels..

Good to see you back 

all the best .

Dave

[Adam J]

59 minutes ago, Skipper Billy said:

In one of the two images I have produced so far this season I have noticed these horrible vertical lines as shown in the attached two images.

Red and green were taken before the meridian and appeared at the top left of the image and the blue was taken after the meridian and appeared bottom right of the image.

Given that the colour of the lines matches the filters I am thinking its a camera problem.

Its a 5 year old  Atik 16200 mono CCD and a full set of bias, flats and darks were used to calibrate the image although they are 'library' calibration frames and were taken about a year ago.

Maybe a new set of calibration frames would cure it or maybe my camera is on its way out???

Any pointers or suggestions most welcome!

(I have deliberately overstretched the images to make it easier to see the lines)

so with it being mono this is likely just a single bad column that is moving about between exposures. Just update your calibration frames and it will be fine, this is normal as the sensor ages and it's not on its way out. Sometimes these artifacts even vanish again over time. Also make sure your using bad pixel rejection when stacking. 

A year is too old for cal frames. 

 

Adam 

Edited January 25 by Adam J

[Skipper Billy]

52 minutes ago, Laurin Dave said:

Looks like a dead column or two David..  easy to fix in Pixinsight using the linear Defect List option in Cosmetic Correction ...  so if you have Pixinsight ...open a raw sub open Cosmetic Correction and click on Defect List, click on the bad column and it should be recognised..  Then run CC ...  if doing WBPP set up CC as a template before hand and apply it in WBPP..   Also works well for correcting this sensors hot pixels..

Good to see you back 

Thanks Dave

I just had a horrid feeling that this problem had appeared suddenly and that the camera was breathing its last!

All the best.

David

[Skipper Billy]

21 minutes ago, Adam J said:

so with it being mono this is likely just a single bad column that is moving about between exposures. Just update your calibration frames and it will be fine, this is normal as the sensor ages and it's not on its way out. Sometimes these artifacts even vanish again over time. Also make sure your using bad pixel rejection when stacking. 

A year is too old for cal frames. 

Thanks Adam

I dither every frame so it makes sense that it moves about.

I will remake the cal frames. I was just so excited to be able to the obsy roof and grab a clear night after being laid up for months! 🙂 

Interesting that they can sometimes vanish over time !

All the best

David

[ollypenrice]

To back up Dave, above, AstroArt can also correct identified-column defects. You just need to know what column it is on the x axis, plug this in on the third page of 'Preprocessing' and stack as usual. The defects will vanish. I used my CCDs like this for many years so being on the way out is a slow process. What I have never seen, though, is a column defect which varied between filters. If it's caused by dither, you're using a big dither for a CCD. Just identify where the line lies on the x axis and see if it's the same. I think it will be.

Olly

[TakMan]

Hi David....

And APP also has the facility to correct for bad column defects:

2) Calibrate > Cosmetic Correction > Hot Column Kappa (set to default 8.0)

This sorts my 2x bad columns out automatically (I don't have to tell it which they are, plus I also dither between shots like yourself).

Damian

 

[Nigella Bryant]

Glad to see you back and posting. 

[Skipper Billy]

30 minutes ago, TakMan said:

And APP also has the facility to correct for bad column defects:

2) Calibrate > Cosmetic Correction > Hot Column Kappa (set to default 8.0)

This sorts my 2x bad columns out automatically (I don't have to tell it which they are, plus I also dither between shots like yourself).

Cheers Damian - I am a Pixinsight user but I will have a look at APP - it sounds interesting!

[Skipper Billy]

8 minutes ago, Nigella Bryant said:

Glad to see you back and posting. 

Thank you! 🙂 

[Skipper Billy]

Wee update in case anyone else has the same problem and reads this.

I found the way in Pixinsight to make a Cosmetic Correction script that WBPP can be pointed at that once created, removes the dead pixel lines to perfection on every single sub automatically.

It worked an absolute treat!!!