The cosmos at our fingertips.
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lior
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by lior » Mon Oct 25, 2004 5:20 pm
Take a look at this very special cosmic ray hit:
Taken form the image mk041016ut093141D.fits
I have never seen such a cosmic ray hit.
Tilvi, look out. It looks exactly like a meteor, but isn't.
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tilvi
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by tilvi » Mon Oct 25, 2004 6:07 pm
Lior,
If this is a cosmic ray and not instrument fault, then its really inteteresting. Can be a discovery. Because it looks like that this cosmic ray source is really moving so fast and giving out such cosmic hits, which resembles a moving meteoroid.
I assume that this FITS file is a Dark frame which is taken when CCD is turned off. The .JPG frame isn't availbale for this frame online. Is it purposly not included because of this dark frame subtraction?
Tilvi
Michigan Tech. University, MI.
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lior
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by lior » Tue Oct 26, 2004 5:25 am
Tilvi,
Indeed this is a dark frame. That is why I think it is not a meteor. Dark frames do not have jpgs on the server, but you can examine the FITS file itself at:
http://nightskylive.net/mk/mk041016/mk0 ... 3141D.fits
The FITS image is even more impressive than the JPG. Examining the FITS file, I think that an instrumental fault is highly unlikely in this case.
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tilvi
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by tilvi » Tue Oct 26, 2004 4:14 pm
lior wrote:Tilvi,
Indeed this is a dark frame. That is why I think it is not a meteor. Dark frames do not have jpgs on the server, but you can examine the FITS file itself at:
http://nightskylive.net/mk/mk041016/mk0 ... 3141D.fits
The FITS image is even more impressive than the JPG. Examining the FITS file, I think that an instrumental fault is highly unlikely in this case.
Another possibility might be is that, its just another object like an airplane which is transmitting the signals over invisble band and passing over MK station. Because its hard to think that cosmic ray can make such a long trail unless there is a cosmic shower and the particle disintegration is perfectly in just one line. Do we have any information about concam CCD's sensitivity for whole EM spetrum?
And you are right that its most unlikely that its an instrument fault. Do we have dark frame for the same time at HL? if its cosmic source, probably we should be able to see it over both the stations. if its something at very low altitude, then probably won't.
Tilvi
Michigan Tech. University, MI.
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lior
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by lior » Wed Oct 27, 2004 2:07 am
Tilvi,
Checking HL for the same frame taken at the same time is a good idea, but unfortunately there is nothing special in the dark frame at HL.
Just to make things clear, the shutter of the CCD was closed when this frame was taken, so this is not an optical object. The thing that caused it is something that can go through a closed shutter of a CCD.
Anyway, if this is a cosmic ray hit, I would not expect to see a similar hit at the same time at HL.
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fick
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by fick » Mon Nov 01, 2004 8:27 pm
Hi All,
The interesting cosmic ray event is cool but not earth-shakingly bizarre or anything.
It is probably a medium energy muon or high energy electron from a nearby cosmic ray shower. What we are seeing is a charged particle passing through the plane of the ccd pixels at a very shallow angle. As the particle plows into each physical pixel it liberates electrons in the silicon by the process of ionization. The electrons look just like the photoelectrons liberated when the pixel is struck by photons of light. So you get an image in the form of the string of hit pixels.
Brian
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lior
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by lior » Tue Nov 02, 2004 1:19 am
Thanks fick,
This cosmic ray hit by itself is not really special, but it is the first time we see something like this in CONCAM.
Since we do some meteor resarch with CONCAM, it is also important not to confuse cosmic ray hits with meteors trail which look very much alike.