Starship Asterisk*

[quote]iamlucky13[/quote]

Thanks! I hadn't considered the direction of the tail at all...

Fantastic! APOTD is the best.

The vivacity of the time-lapse video is definitely a different perspective on comets than I'm used to. It's pretty cool to see the tail "billowing" in the solar wind. Plus the "clouds" of presumably solar particles streaming past. Wow.

[quote="ian"]A friend just posed the question: if each frame in the movie spans 45 minutes then how come there is not more parallax 'drift' between the comet and the background stars?

Is it just a fortunate configuration of the comet's orbit, the spacecraft's orbit and the rotation of the spacecraft to track the comet? [/quote]

I think it's simply because of the distances involved. The comet is roughly the same distance from the earth as the sun, so it takes a fair amount of motion to translate into a significant angular change. Plus, the motion of STEREO spacecraft around the sun may roughly match that of the comet, reducing the background drift. The odds of the motion being constructive rather than destructive are 50-50 (comet traveling in the same direction around the ecliptic plane as the spacecraft).

If you watch the video closely, you'll notice that not only does the comet move vertically with respect to the background stars, but it also moves horizontally relative to the saturation line, apparently reversing directions on that axis.

Also, remember that the tail of a comet does not stream behind it in the direction of travel, but rather away from the sun. As a comet makes its closest approach to the sun, the tale and the trajectory are actually 90 degrees different. The motion of the comet is deceptive.

This is one of the more amazing APoD's in a while!
Very [b]WOW[/b]!!!!
8)

[quote="worm"]What are the three vertical lines? I don't think they could be satalite tracks due to the position of the STEREO A spacecraft that took the picture. Are they artifacts from the camera?[/quote]
They look like blooming artifacts. These result from electrons bleeding along CCD columns from oversaturated pixels. In this case, there are presumably three bright stars outside the cropped field of the animation (note that the lines track the stars, not the comet).

What are the three vertical lines? I don't think they could be satalite tracks due to the position of the STEREO A spacecraft that took the picture. Are they artifacts from the camera?

This is spectacular.

A friend just posed the question: if each frame in the movie spans 45 minutes then how come there is not more parallax 'drift' between the comet and the background stars?

Is it just a fortunate configuration of the comet's orbit, the spacecraft's orbit and the rotation of the spacecraft to track the comet?

I feel I should be able to answer this but I can't, so it's over to you guys...

Thanks.

wow is right, this is quite fantastic!

This is more like it! This is exactly what APOD should be showing. Great stuff.

[quote="goredsox"][url]http://antwrp.gsfc.nasa.gov/apod/ap071003.html[/url]

Wow!! It looks like the coronal mass ejection occurs in three waves. The first wave almost carries the comet tail away, the second wave knocks the tail off completely. By the time the third, smaller wave passes, the tail has grown back.

It really makes one wonder about the tremendous electrical energy in those ejections. If only there was some way to harness that energy as it passed earth.[/quote]

I said the same thing last week after looking at the dark spot on the sun.
Its truly is spectacular we can see the coronal mass ejection wash over the comet. It would be interesting to find out if the ejection effected the mass and trajectory of the comet.

[url]http://antwrp.gsfc.nasa.gov/apod/ap071003.html[/url]

Wow!! It looks like the coronal mass ejection occurs in three waves. The first wave almost carries the comet tail away, the second wave knocks the tail off completely. By the time the third, smaller wave passes, the tail has grown back.

It really makes one wonder about the tremendous electrical energy in those ejections. If only there was some way to harness that energy as it passed earth.