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Horizontal lines through each star - any suggestions as to the cause?

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#1 AMcD

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Posted 28 February 2021 - 05:15 AM

I have an SXV M7 attached to my TS152 Achromatic.  Whilst setting up my new ZWO EAF this evening and calibrating the autofocus I noticed that in the images being produced by the camera all the stars had horizontal bands through them as demonstrated in the TIFF image attached.  Does anyone have a suggestion as to what is going on?

 

I have a fixed installation so tend to leave my CCD's on all the time.  I wonder therefore whether this is a very bad noise issue and that I should in fact turn them off between sessions.

 

Banded-Stars-SXV-M7-JPEG.jpg



#2 sg6

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Posted 28 February 2021 - 05:38 AM

Sort of looks like micro prism problems.

Not sure there is a great deal you can do, think there is but better wait for someonw with greater specific knowledge then myself to offer an idea.

 

What sensor is in the camera?

 

OK, may not be. Sensor is given as:

CCD type:   Sony ICX429AL ‘Exview’ interline CCD imager.

CCD size:   Active area       6.47 x 4.83mm

Pixel size:    8.6 x 8.3uM

 

Basically not sure if CCD's had microprisms.

SXV-M7 Manual might be useful to you.


Edited by sg6, 28 February 2021 - 05:51 AM.


#3 Tapio

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Posted 28 February 2021 - 05:51 AM

This camera is old generation.
It has these modes 'Progressive' and 'Interlaced'.
Interlace mode could look like this.
What software did you use taking this?

#4 the Elf

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Posted 28 February 2021 - 06:44 AM

Looks like corrupted or not correctly interpreted data. Maybe you accidentally selected a mode that is not supported by your software.



#5 AMcD

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Posted 28 February 2021 - 08:51 AM

Many thanks everyone. 

 

I had indeed changed software last night as I was setting up the ZWO EAF on SGP and was using the M7 for the first time with SGP. 

 

Now I have done some digging, I have found that a box called "Equalize Frames" in the "Interlaced Adjustments" section of the ASCOM SX Camera Setup panel was checked. 

 

I have unchecked the box and will try again tonight with this new setting to see if this fixes the issue. We are having an amazing run of clear nights in the middle of the UK at the moment. 

 

Many thanks again for your help with this.

 

A



#6 Churmey

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Posted 28 February 2021 - 08:58 AM

You didn't by chance do your capture in 8 bit mode instead of 16 bit mode did you?


Edited by Churmey, 28 February 2021 - 08:59 AM.


#7 AMcD

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Posted 28 February 2021 - 09:54 AM

You didn't by chance do your capture in 8 bit mode instead of 16 bit mode did you?

That is possible, yes.  A box called "M26C 2X2 color binning" in the "Binning Control" section of the ASCOM SX Camera Setup panel was also checked.  My understanding of binning is somewhat nascent but I wonder whether this could result in an 8 bit image rather than a 16 bit image.

 

All this shows that in my enthusiasm to install a new bit of kit I neglected the details laugh.gif



#8 Tapio

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Posted 28 February 2021 - 10:21 AM

Nope, binning has nothing to do with 8 or 16 bit.
Neither does 8 bit do something like that.

#9 michael8554

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Posted 28 February 2021 - 12:39 PM

Looks to me too like an Interlace problem.



#10 AMcD

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Posted 28 February 2021 - 04:26 PM

I think it is almost certainly the problem. 

 

SGP does not appear to be reading the M7 in 'Interlaced' mode (apparently, there is a well recognized phenomenon with the SXVs when used in 'Progressive' mode called the Venetian Blind effect, which what I appear to be seeing when using it with SGP).  I have tried the M7 again with Nebulosity and the images are fine.

 

What I cannot find is a way to force SGP to read the M7 in 'Interlaced' mode.  I understand that Maxim DL has a driver that allows it to read the SXVs in 'Interlaced' mode but I cannot find anything similar for SGP or a setting in the ASCOM SX Camera Set up that will make SGP do so.

 

I wonder whether I have reached a point where a more modern mono camera is called for...that would be a real shame lol.gif




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