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phenomenon in vicinity of the sun
Posted: Tue Oct 01, 2013 9:24 am
by Gershon
Hello,
i am not an astronomer - just one, who follows APOD and other astronomy information sources out of interest.
On helioviewer.org I have found an image that I found interesting. It shows a phenomenon close to the sun, in the lower left corner.
http://helioviewer.org/?date=2013-06-30 ... abels=true
I have been looking for some scientific views on what this phenomenon may be.
Any reply would be appreciated.
Thanks.
Gershon
Re: phenomenon in vicinity of the sun
Posted: Tue Oct 01, 2013 1:53 pm
by geckzilla
I would guess it's not actually a thing but rather an anomaly produced by the instrument. I tried finding documentation on anomalies COR 1 might encounter but all I can find is a bunch of stupid crap about aliens.
Re: phenomenon in vicinity of the sun
Posted: Tue Oct 01, 2013 2:13 pm
by Beyond
Whatever it is, it certainly is Big. I can't get it magnified enough with out it's disappearing off the screen. However, by using a hand-held magnifying glass, i can make out a few details.
Part of the left and right sides are obscured by denser material. The upper edge has two distinct circular ridges that do not encompass the whole thing. The center part seems to have an irregular surface, is rather round, and when viewed through my hand held magnifier, resembles a face with a tight white cap on it's head. Heading off the lower back from the center, there are no ridges. It looks rather flat, with a few irregularities. To get a better look at it, one needs to be able to adjust the picture so when you zoom, you don't lose the object off the screen.
Re: phenomenon in vicinity of the sun
Posted: Tue Oct 01, 2013 2:15 pm
by geckzilla
Finally found a description of image artifacts including specifically the ring artifact.
http://stereo.gsfc.nasa.gov/artifacts/a ... ound.shtml
There are also some permanent artifacts in the instrumental backgrounds of the COR1 telescopes. Since these artifacts are always there, in a perfect world they would be removed in the background subtraction process. However, they are sensitive to small moment-by-moment changes in the spacecraft pointing, and thus cannot be completely removed. The artifacts are demonstrated in the images below. (Only a few representative artifacts have been circled.) They are caused by small defects in the field lens of each COR1 telescope, though some have also appeared since launch due to the migration of individual dust particles onto the surface of the field lens. Although they can appear anywhere within the image, they are most visible near the edge of the occulter. These artifacts appear as bright rings with a dark center, reflecting the shape of the input aperture with the occulter in the center. Generally, only one side or edge of the ring is visible, giving the artifact a "fingernail" appearance.
Emphasis mine.
Re: phenomenon in vicinity of the sun
Posted: Tue Oct 01, 2013 2:38 pm
by Beyond
I couldn't find anything at the Stereo Learning center that looked like the phenomenon.
What you wrote, geckzilla--> These artifacts appear as bright rings with a dark center, reflecting the shape of the input aperture with the occulter in the center.<-- could possibly fit, however, there is no picture of it to compare it to, to make sure, that i could find.
Re: phenomenon in vicinity of the sun
Posted: Tue Oct 01, 2013 3:01 pm
by geckzilla
There is no image accompanying the description in that article. See the link in the original post for an example.
Re: phenomenon in vicinity of the sun
Posted: Tue Oct 01, 2013 3:08 pm
by geckzilla
Reading it again, the ones in the image are probably the same thing but the appearance is different when further from the center. I'd like to see more examples too but that's the best I could find. There's another neat page about debris flying off the satellite when micrometeorites strike the outer insulation.
http://stereo.gsfc.nasa.gov/artifacts/a ... bris.shtml
Re: phenomenon in vicinity of the sun
Posted: Tue Oct 01, 2013 3:51 pm
by Beyond
Ok, i used the equipment at the original post link to make a day-long movie. (it tells you it takes 3-minutes, but it lies through it teeth
) Anyway, as the camera shakes/vibrates, the object in question does also, which means the phenomenon is one of the built-in artifacts and most likely the thumbnail one, that as you said looks a bit different because it's further from the center.
When in doubt... make a movie of it.
