[Chaos-l] Nice Animated GIF Of Comet Lulin

[Joe Pedit]

It is easier to see that the majority of streaks in the video are 
probably geosynchronous satellites if you composite the individual frames.
http://www.unc.edu/~pedit/lulin.jpg
The field of view is roughly four degrees across with the long axis 
skewed slightly counterclockwise from an east-west orientation. It takes 
about ten frames for the streaks to cross the field, which would suggest 
1.6 minutes between starts of individual frames (which is a bit shorter 
than 61 frames in two hours).

By coincidence, I imaged a few geosynchronous satellites last Friday 
from Jordan Lake. They appear as dots in a fixed tripod image.
http://www.unc.edu/~pedit/geo_sat_7517.jpg

An animation of the comet over a 90 minute period taken last Friday from 
Jordan Lake is at
http://www.unc.edu/~pedit/Lulin0221.html

Joe

> I think those streaks that kept appearing were satellites rather than 
> meteors.  I did "mispeak" about the stars "slewing" past, though.  Let 
> me clarify my hypothesis...
> 
> Meteors probably would have been to brief to appear at in the time-lapse 
> movie and even if they did show up, they would have passed through the 
> field way too fast to be appear like for so long in that movie.  Each 
> image of the "movie" showed a steak about an "inch" long in the frame.  
> Orbiting satellites would also have moved too quickly to appear as short 
> streaks in each exposure.  If they were geosynchronous satellites, the 
> apparent motion (which showed up a the short streak in each image) would 
> be due not to the relative motion of the satellites, but to the slewing 
> of the telescope to counter the rotation of the Earth (and make the 
> stars appear stationary).  It seems to me that the telescope slewing 
> speed would be the only motion slow enough to keep those lights in the 
> frame for so long (since even a split second in that film would have to 
> represent a minute or more in real time).  Furthermore, the position of 
> the meteor at that time had to be near the ecliptic (since it was near 
> Saturn) which is where you would expect to see geosynchronous satellites.
> 
> I had some similar pair of apparitions appear in some webcam images I 
> made a few years back, and this was the explanation given to me by 
> someone on a listserve.   I was hoping they were invading alien ships, 
> but I must admit that the satellite explanation seems more likely.  The 
> guy even looked up some satellites and told me which ones they probably 
> were.  Now that might be interesting to figure out--which satellites 
> they could have been if that's indeed what they were....
> 
> Chris Breivogel
> CHAOS member wanna-be