Some help with 2 specific SOHO images.

[michaelmozina]

In looking through the Lasco-C3 images today, I came across two images with some sort of 'feature/artifact' that I'm curious about. The time stamp on the two images are:

2009/11/11 12:18 (faint outline of wide band is visible along the left side of that image)
2009/11/13 09:18 (A very bright outline of the same effect show up in the this image in another location)

Any ideas would be helpful. I'll try to round up the actual images, upload them and post a link a bit later on this evening. There's definitely something "unusual' going on in those images. I'm just curious about the "cause" of those bands.

 

[MeteorWayne]

I must say, I am at a loss with your obsession to search for some hidden meaning in obvious imaging artifacts. I would suggest you do what what I do; write to the team and let them explain it to you. Why do I have to do all the work in tracking down the explanations for what is an obvious data defect?

Sheesh!

Wayne

 

[michaelmozina]

I must say, I am at a loss with your obsession to search for some hidden meaning in obvious imaging artifacts.

I'm simply trying to understand exactly what caused these specific types of "artifacts" and to make sure that they are in fact "artifacts".

I would suggest you do what what I do; write to the team and let them explain it to you. Why do I have to do all the work in tracking down the explanations for what is an obvious data defect?

You don't have to do that Wayne. I was simply asking for help on a public forum that is frequented by many scientists that I respect a great deal, including you. I saw these two images and I simply wondered what caused them. I thought someone here might have seen them before, gone through the process before, and had a quick answer.

 

[SpaceTas]

It sure would help having the images, or a direct link to them.
Then I'll have a look.

 

[nimbus]

I think what Wayne might be getting at (in part at least) is that there's no mystery to the artifacts. They aren't astronomical unknowns probed by sensors AUs or LYs away, but simple electronics designed from head to toe by people right here on earth using well-known building blocks. A comparable instance would be RLB2 who quoted a few images of a meteorite with some bare metallic surfaces' specularity shining thru and saturating the CCDs in typical "bleeding" peaks of flat white, as some kind of liquid dripping off the meteorite.
You'd asked a few years back about a periodical saturation trail effect on some inner planet filmed by SOHO or another probe looking at the sun. So it's a bit surprising that you'd still not have covered the small amount of electronics material to give you a clear and precise idea of how these artifacts happen, considering how curious the effect appears to you.

http://www.eso.org/~ohainaut/ccd/CCD_artifacts.html

 

[nimbus]

 

[nimbus]

And the C3 pics in question:

 

[SpaceTas]

Thanks Nimbus for posting the images and the link. There was another web page on CCD artifacts, which had other examples like airplane trails, and an real bug on a flat fiat field and not in images. Couldn't find the page: recall it was from MDM observatory.

I am not a SOHO person, but have used a lot of astronomical ccd's (x-rays and optical). So I'll take my best guess at these 2 images.

Image 2009/11/11: not sure but looks like an internal reflection which could happen in very specific orientations as something on the satellite picks up a glint of sunlight, moonlight.
Image 2009/11/13: definitely moving images of the telescope aperture, probably combined with a double internal reflection. Could be the exposure included time when SOHO lost tracking and the solar image moved off axis.


But to michaelmozina i also recommend sending an e-mail to SOHO archive. They would have a definitive answer and would like to know if their quality control failed. Maybe ask one of the amateur astronomers who search for SOHO images for comets. They do excellent work and have found 1600+ comets. http://sungrazer.nrl.navy.mil/.

Wouldn't it be neat to discover a comet rather than image artifacts.

 

[michaelmozina]

I think what Wayne might be getting at (in part at least) is that there's no mystery to the artifacts.

Well, I'm sure that these artifacts may not be mystery to *everyone*, but they are pretty mysterious to me personally.

They aren't astronomical unknowns probed by sensors AUs or LYs away, but simple electronics designed from head to toe by people right here on earth using well-known building blocks. A comparable instance would be RLB2 who quoted a few images of a meteorite with some bare metallic surfaces' specularity shining thru and saturating the CCDs in typical "bleeding" peaks of flat white, as some kind of liquid dripping off the meteorite.

Well, I do realize that equipment was built here on Earth which was why I was hoping that one of those folks here on Earth might shed some light on these images.

You'd asked a few years back about a periodical saturation trail effect on some inner planet filmed by SOHO or another probe looking at the sun. So it's a bit surprising that you'd still not have covered the small amount of electronics material to give you a clear and precise idea of how these artifacts happen, considering how curious the effect appears to you.

http://www.eso.org/~ohainaut/ccd/CCD_artifacts.html

Thanks for that link by the way. FYI, I've looked at a lot of years worth of SOHO images now, and I am familiar with many/most of the artifacts and features associated with these images. Those two images however (thanks for posting them by the way) are/were puzzling to me personally and not something that I am as familiar with.

 

[michaelmozina]

Thanks Nimbus for posting the images and the link. There was another web page on CCD artifacts, which had other examples like airplane trails, and an real bug on a flat fiat field and not in images. Couldn't find the page: recall it was from MDM observatory.

I am not a SOHO person, but have used a lot of astronomical ccd's (x-rays and optical). So I'll take my best guess at these 2 images.

Image 2009/11/11: not sure but looks like an internal reflection which could happen in very specific orientations as something on the satellite picks up a glint of sunlight, moonlight.
Image 2009/11/13: definitely moving images of the telescope aperture, probably combined with a double internal reflection. Could be the exposure included time when SOHO lost tracking and the solar image moved off axis.


But to michaelmozina i also recommend sending an e-mail to SOHO archive. They would have a definitive answer and would like to know if their quality control failed. Maybe ask one of the amateur astronomers who search for SOHO images for comets. They do excellent work and have found 1600+ comets. http://sungrazer.nrl.navy.mil/.

Wouldn't it be neat to discover a comet rather than image artifacts.

Thanks to you and Nimbus for your responses. I appreciate it. FYI, I've 'discovered' many comets in SOHO images over the years. I definitely didn't see all 1600 of them however.

 

[nimbus]

Thanks for that link by the way. FYI, I've looked at a lot of years worth of SOHO images now, and I am familiar with many/most of the artifacts and features associated with these images. Those two images however (thanks for posting them by the way) are/were puzzling to me personally and not something that I am as familiar with.

Alright then, your turn: if those two pics are curious because of the white horizontal peaks next to the 9-o-clock object, how are those different from the cyclical peaks visible on a SOHO video (.gif) from a few years back, where the animated pattern fooled you (general you meaning you and me) into "seeing" something like spokes as in an edge-on pattern, rotating around Venus or Mercury (don't recall what it was exactly)?

A_lost_packet had also replied. I think he ought to remember that topic.

 

[nimbus]

I think the topic I was remembering was yet another one, but here's a past topic with this same general question:
SOHO bleeding effects and recent Hinode images