RCC - Moon - Horizontal Lines! - Forums

Topic starter

Jun 20, 2021

Hello Everyone,

I took this along with many other AVI files and processed them in AutoStakertt and processed them in Gimp. I’m noticing these horizontal lines that you see if you zoom in closer. It’s easier to look at the terminator along the left side of the image. These lines run thru the image but are very hard to see unless you zoom in and look for them.

At 1st I thought it was something that was happening during my processing of these but when I look at the finished image coming out of AutoStakertt they are there but certainly not as prominent. As I sharpen the image they become much more obvious.

Does anyone know what is causing these horizontal lines? I’ve looked at my sensor window and everything is clean.

Some info on the image is:

Gain 120
Bin 1
Mono 8
Frame Size 1600x1200
FPS 42
Output file AVI

Any insight would be greatly appreciated.

Dale

andrea tasselli

Frequent contributor

Jun 20, 2021

You forgot to mention what camera/sensor you are using. My wager would be on that a bias subtraction operation would clear these artefacts.

Dale Penkala

Topic starter

Jun 20, 2021

andrea tasselli:
You forgot to mention what camera/sensor you are using. My wager would be on that a bias subtraction operation would clear these artefacts.

Hello Andrea,

Camera is a ZWO ASI294mc pro. I thought that I have included that however this was an AVI and I’m not sure that my bias frames would be subtracted?

Dale

andrea tasselli

Frequent contributor

Jun 20, 2021

Hi Dale,

If I were you I wouldn't use the AVI format to capture anything astro-related. SER format is the way to go, if you can managed it. Not sure you can do it now but after capturing what you're interested in just shoot a brief sequence (say 10s) with the same exact settings but with the scope cap on and use it in Autostakkert as the source of your bias frames. IOW, stack your bias movie in a master bias and then use it in AS! (image calibration).

Helpful

Ruediger

Jun 20, 2021

Hi Dale,

there are two things coming into my mind:

1. Too high USB transfer speed. That can cause such lines
2. Rolling shutter. The camera you have used is using a rolling shutter and not a global one. This can also lead to strange artifacts.

My favorite is 1 and easy to test. Just reduce to 40% in the driver and check again.
Which software did you use to capture? Some have a high speed option for transfer which can also corrupt data.

CS
Rüdiger

Helpful Insightful Respectful

Dale Penkala

Topic starter

Jun 20, 2021

andrea tasselli:
Hi Dale,

If I were you I wouldn't use the AVI format to capture anything astro-related. SER format is the way to go, if you can managed it. Not sure you can do it now but after capturing what you're interested in just shoot a brief sequence (say 10s) with the same exact settings but with the scope cap on and use it in Autostakkert as the source of your bias frames. IOW, stack your bias movie in a master bias and then use it in AS! (image calibration).

Hi Andrea,
Ok thanks for this info, however I don’t know what SER format is. If my recollection is correct with my ZWO 294mc pro the only movie format options are MPEG and AVI. I’ll have to see if there is an “SER” format.

Thanks and I’ll see if I can try adding my bias frames and repost it here.

Thanks!
Dale

Dale Penkala

Topic starter

Jun 20, 2021

Ruediger:
Hi Dale,

there are two things coming into my mind:

1. Too high USB transfer speed. That can cause such lines
2. Rolling shutter. The camera you have used is using a rolling shutter and not a global one. This can also lead to strange artifacts.

My favorite is 1 and easy to test. Just reduce to 40% in the driver and check again.
Which software did you use to capture? Some have a high speed option for transfer which can also corrupt data.

CS
Rüdiger

Hello Rudiger,
Ok I’m not familiar with the items your have mentioned. The “rolling shutter” never heard this before.

I’m using SharpCap for data capture so where would I change to this “40%”? Is this done in SharpCap?

Thanks!
Dale

Ruediger

Jun 20, 2021

Dale Penkala:
Ok thanks for this info, however I don’t know what SER format is. If my recollection is correct with my ZWO 294mc pro the only movie format options are MPEG and AVI. I’ll have to see if there is an “SER” format.

Hi Dale,

it is depending on the capture SW. If you use ASICapture, the video file is automatically stored in SER format when 16 Bit is selected. When using 8 Bit it stores in AVI.

FireCapture stores in SER format. If you you tell which SW younger using, we can help on detail.

Ruediger

Jun 20, 2021 · Edited: Jun 20, 2021

Dale Penkala:
Ruediger:
Hi Dale,

there are two things coming into my mind:

1. Too high USB transfer speed. That can cause such lines
2. Rolling shutter. The camera you have used is using a rolling shutter and not a global one. This can also lead to strange artifacts.

My favorite is 1 and easy to test. Just reduce to 40% in the driver and check again.
Which software did you use to capture? Some have a high speed option for transfer which can also corrupt data.

CS
Rüdiger

Hello Rudiger,
Ok I’m not familiar with the items your have mentioned. The “rolling shutter” never heard this before.

I’m using SharpCap for data capture so where would I change to this “40%”? Is this done in SharpCap?

Thanks!
Dale

Hi Dale,

I am not familiar with SharpCap. But if it uses ASCOM it is in the ASCOM settings. If it uses the ZWO native driver kit, this option must be implemented. Maybe a SharpCap user can chim in?

Just google for „CMOS rolling and global shutter“. It is hard to explain in words but there are very good examples in images.
Basically it is the way, how the CMOS is read out. A rolling shutter is reading line by line of the CMOS chip. This has the consequence that every line shows a time offset, whereas a global shutter delivers a consistent image. It freezes the image so to say. And especially for lucky imaging a global shutter has a big advantage and rolling shutter is the second choice.

Here a comparison and the effect of a rolling shutter.

PS: That was also the deciding Argument when I had to chose a proper camera for lucky. I went for the older ASI174, which is already 5 years old, but has a global shutter. And it was the perfect choice. Never regretted.

Helpful Engaging Supportive

Dale Penkala

Topic starter

Jun 20, 2021 · Edited: Jun 20, 2021

Ruediger:
Dale Penkala:
Ok thanks for this info, however I don’t know what SER format is. If my recollection is correct with my ZWO 294mc pro the only movie format options are MPEG and AVI. I’ll have to see if there is an “SER” format.

Hi Dale,

it is depending on the capture SW. If you use ASICapture, the video file is automatically stored in SER format when 16 Bit is selected. When using 8 Bit it stores in AVI.

FireCapture stores in SER format. If you you tell which SW younger using, we can help on deta

Ruediger:
Dale Penkala:
Ok thanks for this info, however I don’t know what SER format is. If my recollection is correct with my ZWO 294mc pro the only movie format options are MPEG and AVI. I’ll have to see if there is an “SER” format.

Hi Dale,

it is depending on the capture SW. If you use ASICapture, the video file is automatically stored in SER format when 16 Bit is selected. When using 8 Bit it stores in AVI.

FireCapture stores in SER format. If you you tell which SW younger using, we can help on detail.

Hello Ruediger
Boy I'm not following the acronyms here so what is "SW"
BTW I have to say the AVI format is because its 8MONO with my selections. I'll have to try the 16bit but it doesn't give me a mono option in 16bit.

Thanks!
Dale

Dale Penkala

Topic starter

Jun 20, 2021

Dale Penkala:
andrea tasselli:
Hi Dale,

If I were you I wouldn't use the AVI format to capture anything astro-related. SER format is the way to go, if you can managed it. Not sure you can do it now but after capturing what you're interested in just shoot a brief sequence (say 10s) with the same exact settings but with the scope cap on and use it in Autostakkert as the source of your bias frames. IOW, stack your bias movie in a master bias and then use it in AS! (image calibration).

Hi Andrea,
Ok thanks for this info, however I don’t know what SER format is. If my recollection is correct with my ZWO 294mc pro the only movie format options are MPEG and AVI. I’ll have to see if there is an “SER” format.

Thanks and I’ll see if I can try adding my bias frames and repost it here.

Thanks!
Dale

Hello Andrea,
I was able to eliminate the lines in my image. I did what you had mentioned Andrea with the darks and I also used my flats in AutoStakertt. Didn't see where I could use a Bias frame however. I also checked the Row Noise Correction as well. I didn't have that on so maybe that would have helped right from the get go. Now I need to figure out about this SER mode that you and @Ruediger are telling me about.

Here are the images with the corrections now. I think they turned out much better with out the lines now!

Thanks!
Dale

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Dale Penkala

Topic starter

Jun 20, 2021

Here is a cropped image. Probably should have done this before.

Dale Penkala

Topic starter

Jun 20, 2021

Wanted to let @andrea tasselli & @ruediger that I gave you credits in my description of my image.

Thanks!
Dale

Ruediger

Jun 20, 2021

Dale Penkala:
Wanted to let @andrea tasselli & @ruediger that I gave you credits in my description of my image.

Thanks!
Dale

Hi Dale,
that is more than kind. But you solved the problem yourself. We only gave some hints.
But it makes me happy it worked out for you and the stripes are gone 🙂👍

Cheers
Rüdiger

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Dale Penkala

Topic starter

Jun 20, 2021

Ruediger:
Dale Penkala:
Wanted to let @andrea tasselli & @ruediger that I gave you credits in my description of my image.

Thanks!
Dale

Hi Dale,
that is more than kind. But you solved the problem yourself. We only gave some hints.
But it makes me happy it worked out for you and the stripes are gone 🙂👍

Cheers
Rüdiger

I think its only fair that I mention you both as you guys were nice enough to try to help me.

If its ok with you Rudiger I'd like to PM you on this SEM issue that we have talked about. As I was working with some other images I can really see the 8bit is really not a good thing here on the moon with the greyscale. It really shows up.
I think I know where I have to look in SharpCap to make the changes you and Andrea have suggested so I hope to get out on the next clear night and make some settings changes for my imaging the moon and planets.
I did have 1 other image that still had lines in the top 1/4 of the moon shot so I cropped it off. I tryed running it thru AutoStakkert several different times with different filters and I couldn't get that one figured out. Hopefully once I get it switched over to the 16bit raw setting it will help out going over to the SER as you mentioned and hopefully it will give me a better image. Even if it is just a little bit better I'd be happy as long as the lines don't come back

Thanks!
Dale