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ASI533 - MC PRO - Lots of hot pixels


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Hi,

I have an 533MC that is about 8 months old. I do not have another 533 to reference against but I have noticed lately that my darks have a lot of hot pixels, which lately seem slightly more difficult to process away.

The attached is a 300s dark frame at 1x1 bin and room temp (20'C) (and stretched slightly). Does this seem normal to others with a 533 before I think about sending back?

 

 

533.png

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9 minutes ago, Moodtastic said:

Hi,

I have an 533MC that is about 8 months old. I do not have another 533 to reference against but I have noticed lately that my darks have a lot of hot pixels, which lately seem slightly more difficult to process away.

The attached is a 300s dark frame at 1x1 bin and room temp (20'C) (and stretched slightly). Does this seem normal to others with a 533 before I think about sending back?

 

 

533.png

Well at room temp, yes you have to expect that....🤔

Try it at -10 and if still the same then send it back...or buy a CCD... 👍🏼

Edited by Stuart1971
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I'll upload an image later which was taken outside a couple of nights ago and the camera is cooled to -15. It looked similar to the attached.

It might just be the nature of the sensor in the camera, hard to know with nothing to reference against.

Edited by Moodtastic
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1 minute ago, Moodtastic said:

I'll upload an image later which was taken outside a couple of nights ago and the camera is cooled to -15. It looked similar to the attached.

Hmmm, well that’s not good then...

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24 minutes ago, Moodtastic said:

I'll upload an image later which was taken outside a couple of nights ago and the camera is cooled to -15. It looked similar to the attached.

It might just be the nature of the sensor in the camera, hard to know with nothing to reference against.

It's certainly quite different to the 300s sample image on the camera page at FLO - scroll down to the bottom of the page  ASI533 Sample 300s image

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4 minutes ago, Shimrod said:

It's certainly quite different to the 300s sample image on the camera page at FLO - scroll down to the bottom of the page  ASI533 Sample 300s image

The FLO image is still in raw format while the above has been debayered. Above looks just like a raw DSLR dark that has been debayered. 

 

@Moodtastic are you saying that after calibrating your lights the brighter pixels are still present in your lights?

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18 hours ago, Moodtastic said:

I'll upload an image later which was taken outside a couple of nights ago and the camera is cooled to -15. It looked similar to the attached.

It might just be the nature of the sensor in the camera, hard to know with nothing to reference against.

Here's a 300s dark at more or less 20 degrees from my ASI533 if you would like to process the same way for comparison. I've had mine since September but due to cloud cover have yet to use it in anger.

Light_ASIImg_300sec_Bin1_19.8C_gain0_2021-02-13_115158_frame0002.fit

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  • 2 weeks later...

I compared Shimrod's Dark to my ASI-533 at -5°C and there is little difference.  The auto visualization is such a narrow range tends to make it look really noisy.  If you check the value of most of the warm pixels they are no where near swamped.  the second image shows just a little stretching of the visualization makes almost all of the warm pixels go away.  Doing Dark frame subtraction will take care of the warm pixels and dithering is also a good practice.

Dark Frames comp.jpg

Dark Frames comp2.jpg

This is a 60 second single image @ -5°C showing the Debayered image and the Raw

ASI-533MCP single 60s sub.jpg

 

It would be interesting to compare the OP's dark image the same way.

Edited by CCD-Freak
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On 21/02/2021 at 18:31, CCD-Freak said:

I compared Shimrod's Dark to my ASI-533 at -5°C and there is little difference.  The auto visualization is such a narrow range tends to make it look really noisy.  If you check the value of most of the warm pixels they are no where near swamped.  the second image shows just a little stretching of the visualization makes almost all of the warm pixels go away.  Doing Dark frame subtraction will take care of the warm pixels and dithering is also a good practice.

Dark Frames comp.jpg

Dark Frames comp2.jpg

This is a 60 second single image @ -5°C showing the Debayered image and the Raw

ASI-533MCP single 60s sub.jpg

 

It would be interesting to compare the OP's dark image the same way.

Hi CCD - Freak.

Apologies this has taken so long. I have just captured a new dark frame at 20C, 300s. I would be interested to see your comparison with my example.

 

D_2021-02-22_19-36-36_300s__20C.fit

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3 hours ago, Moodtastic said:

Hi CCD - Freak.

Apologies this has taken so long. I have just captured a new dark frame at 20C, 300s. I would be interested to see your comparison with my example.

 

D_2021-02-22_19-36-36_300s__20C.fit 17.26 MB · 1 download

Do you have a Dark taken at your desired operating temperature like -5°C or -10°C?.   I can take a Dark at 20C to match your 20°C you posted.

I will get a comparison posted later this evening.

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Here is the comparison at +20C.  I stretched the images the same amount and there is very little difference.  I was wondering what capture software you use and what was the gain and offset settings.  When I look at the stats of a single warm pixel they are typically around 6k ADU so they are not saturated.  Good Darks and dithering will produce very clean images.  I see no problem with your camera.

Dark Frames comp 20C.jpg

Edited by CCD-Freak
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