A question about the Lasco-C3 images from SOHO

[michaelmozina]

I was wondering if anyone else has noticed the new dark "line" at the 3:00 positiion in the LASCO-C3 images recently.&nbsp; I seems like that's only been there for few weeks.&nbsp; I went back through tthe archives of previous months and I don't see it in earlier images.&nbsp; I'm wondering if this is something temporary caused by the planet that recently passed through that region, or if there is some kind of perminant damage to the equipment?&nbsp; In other words is that something that will be "baked out" during the next bakeout process, or if that is s perminant fixture future LASCO-C3 images? <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>

 

[MeteorWayne]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I was wondering if anyone else has noticed the new dark "line" at the 3:00 positiion in the LASCO-C3 images recently.&nbsp; I seems like that's only been there for few weeks.&nbsp; I went back through tthe archives of previous months and I don't see it in earlier images.&nbsp; I'm wondering if this is something temporary caused by the planet that recently passed through that region, or if there is some kind of perminant damage to the equipment?&nbsp; In other words is that something that will be "baked out" during the next bakeout process, or if that is s perminant fixture future LASCO-C3 images? <br />Posted by michaelmozina</DIV><br /><br />It sure does seem to line up with where Venus passed, from what I recall.</p><p>I'm not sure if it can or will be baked out....IIRC the bake oout is not used on the LASCO cameras, only the other wavelength specific images.</p><p>I'll dig around to see what I can find.</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[michaelmozina]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It sure does seem to line up with where Venus passed, from what I recall.I'm not sure if it can or will be baked out....IIRC the bake oout is not used on the LASCO cameras, only the other wavelength specific images.I'll dig around to see what I can find. <br /> Posted by MeteorWayne</DIV></p><p>I appreciate the information.&nbsp; I don't remember seeing this line until recently.&nbsp; It does seem to be connected with the bleeding effect/ring effect from the planet's passing.&nbsp;&nbsp; I went back an looked through the archives and I don't see it there until just the past couple of weeks. </p> <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>

 

[MeteorWayne]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I appreciate the information.&nbsp; I don't remember seeing this line until recently.&nbsp; It does seem to be connected with the bleeding effect/ring effect from the planet's passing.&nbsp;&nbsp; I went back an looked through the archives and I don't see it there until just the past couple of weeks. <br />Posted by michaelmozina</DIV><br /><br />As of June 14th, the black line is gone. Still looking for an axplanation. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[michaelmozina]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>As of June 14th, the black line is gone. Still looking for an axplanation. <br /> Posted by MeteorWayne</DIV></p><p>I see it's cleared itself up now, but if you do come accross an explanation, I'd be very curous to know what caused that effect.&nbsp; It didn't appear in Lasco-C2 images so it seems to have been some type of camera artifact.&nbsp;</p> <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>

 

[MeteorWayne]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I see it's cleared itself up now, but if you do come accross an explanation, I'd be very curous to know what caused that effect.&nbsp; It didn't appear in Lasco-C2 images so it seems to have been some type of camera artifact.&nbsp; <br />Posted by michaelmozina</DIV><br /><br />While researching (unsuccessfully so far) ran across this:</p><p class="right_p">This whimsical illustration of a sun flower was composed solely of images from the STEREO spacecraft taken on June 6, 2008. It serves to reinforce the fact that STEREO (like SOHO) observes the Sun in four different wavelengths of ultraviolet light and color codes each of these so that scientists and others can immediately know which wavelength was used to take the image. The orange center is from the EUV 304 &Aring;ngstrom wavelength; blue is from EUV 171 &Aring;; green is from EUV 195 &Aring;; and yellow is from EUV 284 &Aring;. Each image captures different features at different temperatures and distances above the sun's surface. The reddish background in the "sun" in the upper right is from STEREO's COR2 coronagraph, an instrument that blocks out the sun to reveal faint features in the sun's corona as seen in visible light. There is some logic to this image: the sun is the driving force of all living things on Earth, including flowers! </p><p class="right_p">&nbsp;</p><p class="right_p">&nbsp;</p><div class="line_separator_right"><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/11/11/6bba3372-5202-43bc-ab3e-2a2dfada1d28.Medium.jpg" alt="" /><br /></div> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[MeteorWayne]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I see it's cleared itself up now, but if you do come accross an explanation, I'd be very curous to know what caused that effect.&nbsp; It didn't appear in Lasco-C2 images so it seems to have been some type of camera artifact.&nbsp; <br />Posted by michaelmozina</DIV><br /><br />I wrote to them and received this reply. It was due to Venus, and now we've gained a bit more understanding about the image processing...</p><p>&nbsp;</p><p>Hi Wayne.<br /><br />You are correct.&nbsp; The defect (anomaly) in the images was a black&nbsp; <br />line.&nbsp; When Venus passes through the field of view it will leave a&nbsp; <br />white line due to overexposure (bleeding) of the pixels.&nbsp; The black&nbsp; <br />line is the subtraction of venus (intensity in pixels) passing through.<br /><br />The corona (area around the sun) which Lasco sees is is quite dim, and&nbsp; <br />to bring out the features, the comets, the CMEs etc, we subtract the&nbsp; <br />base photon signal which varies across the field of view to show these&nbsp; <br />features.&nbsp; The black line was the result of a 7 day&nbsp; (once per day)&nbsp; <br />subtraction image for the week of June 3 while Venus was still in the&nbsp; <br />field.&nbsp; The feature went away abruptly when I updated the subtraction&nbsp; <br />on June 14 for the week of June 10.<br /><br />SOHO thanks you for your question.<br /><br />Kevin Schenk<br />EIT and LASCO Operations<br />NASA-Goddard Space Flight Center, USA</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[michaelmozina]

Thanks for posting Kevin's reply.&nbsp; I appreciate it. <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>

 

[CalliArcale]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Thanks for posting Kevin's reply.&nbsp; I appreciate it. <br /> Posted by michaelmozina</DIV></p><p>Yes, thank you!&nbsp; It's a relief to know that it was something intentional and not damage to the instrument.&nbsp;</p> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[michaelmozina]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Yes, thank you!&nbsp; It's a relief to know that it was something intentional and not damage to the instrument.&nbsp; <br /> Posted by CalliArcale</DIV></p><p>The SOHO satellite is like the Energizer bunny, it keeps going and going and going....... &nbsp; You have to appreciate the quality of s satllite that can take all the charged particle action that the sun can throw at it for more than 10 years, and still keep producing useful socientific images.&nbsp; &nbsp; What a wonderful program. </p> <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>

 

[michaelmozina]

<p>http://sohowww.nascom.nasa.gov/data/LATEST/current_c3.mpg</p><p>FYI, a comet got swallowed around the 4:00 position on 6.16 at around 09:00.&nbsp; Lasco images sure demonstrate that the universe is quite "active". </p><p>&nbsp;</p> <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>

 

[MeteorWayne]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>http://sohowww.nascom.nasa.gov/data/LATEST/current_c3.mpgFYI, a comet got swallowed around the 4:00 position on 6.16 at around 09:00.&nbsp; Lasco images sure demonstrate that the universe is quite "active". &nbsp; <br />Posted by michaelmozina</DIV><br /><br />Good catch; yes another tiny Kreurtz group comet. Poor sucker didn't even make it to perihelion <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>