posted on May, 8 2010 @ 12:09 PM
reply to post by NotAgain
It's a camera artifact and it's been there pretty much since the spacecraft was launched.
Another case of someone not making use of the available resources and learning about what they are looking at when speculating about what they are
seeing. While the images we see always have Solar north at the top of the frame, the spacecraft moves in three axes, including roll. On the STEREO
orbit tool page stereo-ssc.nascom.nasa.gov...
one of the coordinates given is the roll angle from solar north.
On January 1, 2007 (soon after the launch), the roll angle of STEREO A was 29.6º relative to the Sun's north pole. At that time (according to my
sketch below) the "object" appeared at about 99º. On April 2, 2010 the roll was -7.3º, a change of about 37° in a counterclockwise direction. The
"object" was now at about 63º, a change of 36º.
On January 2, 2009, the roll angle was 2.8º and the "object" was at 73º. On May 1, 2009, the roll was -7.2º and the "object" was at 63º. The
difference in roll was about 10º and the difference in the object was (guess what?) about 10º.
The movement of the "object" in the frame corresponds to the roll angle of the spacecraft.
The "object" is a camera artifact.