Any fix for amp glow ASI183MC

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Sean.Wang
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Re: Any fix for amp glow ASI183MC

Post by Sean.Wang » Wed Aug 08, 2018 6:05 am

The bayer pattern is RGGB.
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bellavia
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Re: Any fix for amp glow ASI183MC

Post by bellavia » Wed Aug 08, 2018 12:06 pm

I too cannot get rid of all the amp glow, using a large stack of dark frames that were taken at identical gain, offset, exposure and temperature.

This is a serious issue, that needs to be resolved. It is true for both my 183MM Pro and 183MC Pro.

My most recent experience with non-removable amp glow was at Gain 100 (just below unity), Offset 12 (to prevent clipping the darks), 300 second exposure, -15 deg Celsius, for light frames and dark frames. No bias or flats were used.

Note: I cannot go any shorter than 300 seconds, as I mostly do narrow-band imaging. Even 300 seconds is too short.

I worked very hard on this object (3 nights, while having to go to work the next day), and I am not happy with the end result at all:

https://www.astrobin.com/359918/G/

Steve

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Sean.Wang
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Re: Any fix for amp glow ASI183MC

Post by Sean.Wang » Thu Aug 09, 2018 7:53 am

bellavia wrote:I too cannot get rid of all the amp glow, using a large stack of dark frames that were taken at identical gain, offset, exposure and temperature.

This is a serious issue, that needs to be resolved. It is true for both my 183MM Pro and 183MC Pro.

My most recent experience with non-removable amp glow was at Gain 100 (just below unity), Offset 12 (to prevent clipping the darks), 300 second exposure, -15 deg Celsius, for light frames and dark frames. No bias or flats were used.

Note: I cannot go any shorter than 300 seconds, as I mostly do narrow-band imaging. Even 300 seconds is too short.

I worked very hard on this object (3 nights, while having to go to work the next day), and I am not happy with the end result at all:

https://www.astrobin.com/359918/G/

Steve
Hi Steve
Thanks for your reply. I understand, if amp-glow such as 183, will be hard for long exposure calibration. I think 183mm/mc pro is more suitable for LRGB and short exposure imaging. I think 1600 is better for narrowband imaging, it's amp-glow is smooth.
ZWO | Marketing Consultant
Location:lon=120.6 lat=31.3
SuZhou China

motto:
Don't face one's fate, can't be a real man;
Don't know manners, can't be gentle;
Don't know meaning behind the words, can't understand man's heart.

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Sean.Wang
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Re: Any fix for amp glow ASI183MC

Post by Sean.Wang » Thu Aug 09, 2018 2:43 pm

bellavia wrote:I too cannot get rid of all the amp glow, using a large stack of dark frames that were taken at identical gain, offset, exposure and temperature.

This is a serious issue, that needs to be resolved. It is true for both my 183MM Pro and 183MC Pro.

My most recent experience with non-removable amp glow was at Gain 100 (just below unity), Offset 12 (to prevent clipping the darks), 300 second exposure, -15 deg Celsius, for light frames and dark frames. No bias or flats were used.

Note: I cannot go any shorter than 300 seconds, as I mostly do narrow-band imaging. Even 300 seconds is too short.

I worked very hard on this object (3 nights, while having to go to work the next day), and I am not happy with the end result at all:

https://www.astrobin.com/359918/G/

Steve
Could you upload your dark frames and light frames, we will calibrate by ourselves.
ZWO | Marketing Consultant
Location:lon=120.6 lat=31.3
SuZhou China

motto:
Don't face one's fate, can't be a real man;
Don't know manners, can't be gentle;
Don't know meaning behind the words, can't understand man's heart.

bellavia
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Joined: Mon Nov 27, 2017 2:15 am

Re: Any fix for amp glow ASI183MC

Post by bellavia » Tue Aug 14, 2018 4:36 pm

Hi again,

This is a link to my light (24 X Ha and 24 X OIII) and dark (41X) frames, all 300 seconds long, same gain, offset and temperature (-15C).:

https://drive.google.com/open?id=1K49uW ... 8TJ_90xIks

But except for perhaps one bright line, I am now thinking that the dark frames did calibrate most or all of the amp glow away, and that this is banding.
Dithering might solve this, but my low-end mount can only dither in RA, due to the huge DEC backlash, and RA is also the long direction of the sensor, as I like RA left-right and DEC North-South. But I can can change this and/or try to dither in both directions, with a longer settle time, for the long exposures.

Thanks for looking into this!

Steve

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Sean.Wang
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Re: Any fix for amp glow ASI183MC

Post by Sean.Wang » Wed Aug 15, 2018 2:21 pm

bellavia wrote:Hi again,

This is a link to my light (24 X Ha and 24 X OIII) and dark (41X) frames, all 300 seconds long, same gain, offset and temperature (-15C).:

https://drive.google.com/open?id=1K49uW ... 8TJ_90xIks

But except for perhaps one bright line, I am now thinking that the dark frames did calibrate most or all of the amp glow away, and that this is banding.
Dithering might solve this, but my low-end mount can only dither in RA, due to the huge DEC backlash, and RA is also the long direction of the sensor, as I like RA left-right and DEC North-South. But I can can change this and/or try to dither in both directions, with a longer settle time, for the long exposures.

Thanks for looking into this!

Steve
Thanks, Steve. I will take a look after download complete.
ZWO | Marketing Consultant
Location:lon=120.6 lat=31.3
SuZhou China

motto:
Don't face one's fate, can't be a real man;
Don't know manners, can't be gentle;
Don't know meaning behind the words, can't understand man's heart.

HoHr
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Re: Any fix for amp glow ASI183MC

Post by HoHr » Tue Sep 18, 2018 7:15 pm

At the beginning I had also problem with ampglow but it came from bias frame (?). Without bias amp glow is away. But it seems as dark must be taken at same shootout as light frames. edit: I just found out that images I rejected as being responsible for "negative" amp glow were taken another night at gain=0.

What I still see are some horizontal stripes/lines (on my image visible in background as red moire) or on the image posted on 22 July earlier in this thread. Whole background is uneven despite long integration time (115 x 180sec, darks, flats, gain 45). It's not present on flats or I didn't find it there and image with/without flats shows the same pattern. Cooled, to -35C.

Image is crop from center at 100%, processed in AstroArt.

Is it a good idea to do solar imaging with asi183MC like eclipses and so on?
Attachments
M51_183MC_115x180s.jpg

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Sean.Wang
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Re: Any fix for amp glow ASI183MC

Post by Sean.Wang » Thu Sep 20, 2018 4:40 pm

HoHr wrote:At the beginning I had also problem with ampglow but it came from bias frame (?). Without bias amp glow is away. But it seems as dark must be taken at same shootout as light frames. edit: I just found out that images I rejected as being responsible for "negative" amp glow were taken another night at gain=0.

What I still see are some horizontal stripes/lines (on my image visible in background as red moire) or on the image posted on 22 July earlier in this thread. Whole background is uneven despite long integration time (115 x 180sec, darks, flats, gain 45). It's not present on flats or I didn't find it there and image with/without flats shows the same pattern. Cooled, to -35C.

Image is crop from center at 100%, processed in AstroArt.

Is it a good idea to do solar imaging with asi183MC like eclipses and so on?
Yes, 183mc can do solar eclipse as well.
ZWO | Marketing Consultant
Location:lon=120.6 lat=31.3
SuZhou China

motto:
Don't face one's fate, can't be a real man;
Don't know manners, can't be gentle;
Don't know meaning behind the words, can't understand man's heart.

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