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Posted by: antoniseb Aug 20 2008, 07:24 PM

Over on the BAUT forum, someone pointed out this image

http://www.bautforum.com/attachments/questions-answers/8525d1219249284-soho-c3-13-8-2008-20080813_0918_c3.jpg

I looked through the SoHO images to be sure it wasn't a hoax, and this image did appear on the official sight with no obvious artifact like this in either the image before or after it.

So it is obviously not a giant comet with a coma twice the diameter of the Sun which only appears for a few minutes... it is probably an artifact inside or right next to SoHO. Does anyone have a good guess as to what it is?

Posted by: djellison Aug 20 2008, 07:58 PM

BAUT seems dead at the moment - direct links below

Aug 13th at 0842Z
http://sohowww.nascom.nasa.gov/data/realtime/javagif/gifs/20080813_0842_c3.gif

0918Z with wierd smudge
http://sohowww.nascom.nasa.gov/data/realtime/javagif/gifs/20080813_0918_c3.gif

0942Z without
http://sohowww.nascom.nasa.gov/data/realtime/javagif/gifs/20080813_0942_c3.gif

Looks like some sort of optical phenomenon - who knows - cool image none the less.

Posted by: hendric Aug 20 2008, 08:02 PM

Looks to me like a floating piece of lint in the optics, that is out of focus.

Posted by: antoniseb Aug 20 2008, 09:39 PM

I just mentioned this same idea over on BAUT. This 'event' occured during the Perseids. I wonder if some tiny dust particle collided with the camera lens during the exposure, and the haze we see is from a tiny amount of vaporized glass' smoke trail while the shutter was open.

BTW, I've done no math or other physics to guess what such a pattern would look like.

Posted by: Circum Aug 20 2008, 11:15 PM

I'm having a bit of difficulty visualizing what 'during the Perseids' could even mean, since isn't SOHO about a million miles away?

Posted by: NGC3314 Aug 21 2008, 03:43 AM

The feature appears pretty accurately radial to the Sun's location at the field center, which is a common property of internal reflections in complex optical systems. I'm wondering whether there could have been an excursion in the spacecraft pointing which let light from the innermost corona (let alone the photosphere) somewhere that gave in internal reflection in the camera. If bright enough, what shows up in that image could even be the inompletely scrubbed afterimage of a very bright stimulus.

Posted by: antoniseb Aug 21 2008, 09:33 AM

The Perseids cut a fairly wide swath through the solar system. The Earth, moving at 19 miles a second, is in them for a few days (millions of miles).

Posted by: vk3ukf May 29 2009, 12:42 AM

Hi,

I also have something that I would love to have explained in detail.

http://www.qsl.net/vk3ukf/Soho.html

You'll find a still image and a close up, several short videos from SOHO showing the anomaly.
The explanation was error correcting software?

This appears on several frames at different wavelengths.

Would love to know more about the optics, is there one CCD for the different wavelengths?

Posted by: djellison May 29 2009, 07:28 AM

One thing is for sure - it's not a 'real' object out in space. Nothing could remain stationary like that.

Each wavelength is actually a different telescope, with different optics and a different CCD. What the explanation is, I don't know.

Posted by: ugordan May 29 2009, 08:31 AM

Well... A big, black rectangular monolith could...

*ducks*