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Jairo
2011-Jun-09, 02:25 PM
A CT complained about a different block in a SOHO image. It's on the uper right:
http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2011/c2/20110604/20110604_1422_c2_1024.jpg

I have seen it happening before. What causes that?

Thanks.

Jairo
2011-Jun-09, 02:27 PM
It's kind of subltle. It's like a rectangle taken from another SOHO image. It seems like the background, but they don't match perfectly.

Bobbar
2011-Jun-09, 07:52 PM
I think I see what you are talking about.

Levels - Darkened (http://i.imgur.com/lO3yV.jpg)

Levels - Darkened - Highlight (http://i.imgur.com/j2rj2.jpg)

I'm sure the answer you are going to get is going to be something along the lines of transmission/compression artifacts.

phunk
2011-Jun-09, 08:36 PM
The block matches the previous image in the series, 12 minutes earlier:

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2011/c2/20110604/20110604_1410_c2_1024.jpg

phunk
2011-Jun-09, 08:38 PM
And it's not just a small block, it's an entire strip of the image top to bottom.

Hal37214
2011-Jun-09, 08:40 PM
I don't know if these SOHO images are mosaics, or single-frame raster scans, but in either case it looks to me like a variation in the coronal radiation occurred between the times when the two different parts of the image were composited.

phunk
2011-Jun-09, 08:45 PM
I'd guess that a chunk of data for that image was lost in transmission error, and it was filled in with the previous image to make it look better. Remember, this isn't raw data we're looking at, it's processed to make pretty pictures for the web.

Jairo
2011-Jun-10, 12:30 AM
Thank you all for the explanations. Are the raw imagens available too?