<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. It didn't appear in Lasco-C2 images so it seems to have been some type of camera artifact. <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> </p><p>Hi Wayne.<br /><br />You are correct. The defect (anomaly) in the images was a black <br />line. When Venus passes through the field of view it will leave a <br />white line due to overexposure (bleeding) of the pixels. The black <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 <br />to bring out the features, the comets, the CMEs etc, we subtract the <br />base photon signal which varies across the field of view to show these <br />features. The black line was the result of a 7 day (once per day) <br />subtraction image for the week of June 3 while Venus was still in the <br />field. The feature went away abruptly when I updated the subtraction <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>