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Normal hot pixels or did I damage my sensor?

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#1 Deesk06

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Posted 10 April 2020 - 07:50 AM

Ill give a quick back story. 

 

I was imaging for the first time this week and trying to figure out my capture software. well I set it up to take like 80 exposures of about 60 seconds. Come back out an hour and 20 min later to check on my light frames, only to see that there were just two light frames, which were my test shots. Upset, but no big deal I am a beginner. Maybe I had the location file wrong or the camera was not working properly. So I go to my camera and that's when I notice it has been taking a single exposure for OVER AN HOUR. Yikes! I immediately stopped it and broke down my equipment thinking I could try the next night. At this point I was blaming the capture software for not working properly to my parameters. So I go and set up the next night. This time I sit near the camera and watch it take my frames for about 10 minutes. Browsing cloudy nights at the same time etc. All looks good this time; must have been a hiccup with the software the previous night.  Off I go to let it be for another hour. Well, I come back out and there it was again, a SINGLE 45 MINUTE EXPOSURE! I am cursing now wondering **** is going on. Then it hit me. I had the CPU go into rest mode after 1 minute of down time. I thought since I had the capture software running it wouldn't allow it to go into rest mode. Finally figuring it out after super deep-frying my sensor for 2 hours basically. 

 

Anyway, that is where I am at now. I see a lot of hot pixels in my images now, usually 60" exposures. I am not sure if they were always there and it is normal or if these hot pixels were a cause of those super deep-fried long exposures. 

 

 



#2 Madratter

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Posted 10 April 2020 - 07:57 AM

Odds are strong they were already there. I looked at the image to the extent possible without seeing it full size and compressed to boot, and I didn't see anything that made me go Yikes!


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#3 OhmEye

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Posted 10 April 2020 - 08:15 AM

I don't see a mention of what camera you have. Mine don't have a shutter, so they have photons hitting the sensor all the time while the lens isn't covered. That includes during cooldown before it gets dark and even my shortest exposure time would be a 100% white image. I doubt you did any damage.

 

My bad pixel map has hundreds of bad pixels. Which is ok, they process out and it's not a significant percentage of my camera's 20 million pixels.



#4 AstroBrett

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Posted 10 April 2020 - 08:19 AM

I agree 100% with Madratter. If your post-processing software has a provision for mapping of defects, it would be worth your time to do so. I can see a number of hot blue and red pixels even on the reduced image, and that will take care of those during calibration. It will take an hour or so, but once you save it and use it as part of your calibration, it will greatly improve your results.

 

Brett  


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#5 Michael Covington

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Posted 10 April 2020 - 08:29 AM

If a one-minute exposure wouldn't damage the sensor, neither would a 45-minute exposure.  Sensors are very robust.  Most of them are more tolerant of bright light than your eyes are.  The world is full of security cameras, all-sky cameras, etc., that even have the sun pass through their field regularly.



#6 Deesk06

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Posted 10 April 2020 - 08:30 AM

I agree 100% with Madratter. If your post-processing software has a provision for mapping of defects, it would be worth your time to do so. I can see a number of hot blue and red pixels even on the reduced image, and that will take care of those during calibration. It will take an hour or so, but once you save it and use it as part of your calibration, it will greatly improve your results.

 

Brett  

great thanks! Maybe my kappa setting was incorrect, but I did try to correct the hot pixels. I will need to do some more research on it. 



#7 Deesk06

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Posted 10 April 2020 - 08:31 AM

I don't see a mention of what camera you have. Mine don't have a shutter, so they have photons hitting the sensor all the time while the lens isn't covered. That includes during cooldown before it gets dark and even my shortest exposure time would be a 100% white image. I doubt you did any damage.

 

My bad pixel map has hundreds of bad pixels. Which is ok, they process out and it's not a significant percentage of my camera's 20 million pixels.

Okay good! I am glad. I thought it would have damaged the sensor. The camera is a canon 1000D



#8 JIM262

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Posted 10 April 2020 - 09:14 AM

Isn't that the Horsehead Nebula in the right upper corner?  If so, wow for a beginner, that is a great capture.


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#9 OldManSky

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Posted 10 April 2020 - 09:22 AM

Canons (and other DSLRs) can have the sensors heat up during long exposures (or long stretches of video recording/live view).  Most Canons, though, have a sensor temp shutoff (not sure about your model) that will automatically shut off an exposure or turn off video/live view if the sensor gets too warm.  If yours didn't shut off, and it doesn't sound like it did, you should be fine.


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#10 Deesk06

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Posted 10 April 2020 - 10:06 AM

Isn't that the Horsehead Nebula in the right upper corner?  If so, wow for a beginner, that is a great capture.

It is indeed. When I stretched it and saturated it, it was very visible. Although in my editing I was not focusing on it at all. and was contemplating cropping it out. I am going to image it in the future so I did not want to ruin the surprise for myself.  Otherwise it is just a decent exposure. I do not think it is that great since I am missing a big chunk of the Orion nebula. I need more data. Thanks!



#11 Deesk06

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Posted 10 April 2020 - 10:08 AM

Canons (and other DSLRs) can have the sensors heat up during long exposures (or long stretches of video recording/live view).  Most Canons, though, have a sensor temp shutoff (not sure about your model) that will automatically shut off an exposure or turn off video/live view if the sensor gets too warm.  If yours didn't shut off, and it doesn't sound like it did, you should be fine.

Nope it did not turn off at all. I am glad I did not screw up my camera !



#12 TelescopeGreg

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Posted 10 April 2020 - 01:01 PM

What OldManSky said.

 

If nothing else, this is very tangible evidence of the value of a cooled camera.  I discovered it myself one night where I did my normal imaging session (taking a bunch of 30-ish second subs), then did some video imaging of Jupiter.  Video on a DSLR means that the back screen is kept on, and of course, the sensor is going full-speed with the mirror up.  After doing all that I realized that I hadn't taken my Darks yet for the imaging run, so I put the cover on the telescope and fired up the intervalometer for the Darks while I packed everything else up.

 

Next morning I took a look at what I got.  Talk about hot pixels!  The Darks started out GRAY, not black, and got progressively darker over the course of the next half dozen images as the sensor cooled.  Yeah...  No damage, of course, just a reflection of how sensitive these parts are to temperature. 


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