Leo S Offline Upload & Sell: Off
|
Nice composite David. I personally think it would be more striking without the sporadic.
dgdg wrote:
I assume 180 degrees from the radiant they appear parallel since they are near to us as they burn up in the atmosphere, unable to cause an infinity point convergence perspective.
Actually, the paths of meteors of the same shower, in this case Perseids, are always more or less parallel to each other. This property is the reason it's possible to classify any meteor as belonging to the Perseid meteor shower, and the reason why meteors appear to us to radiate away from the radiant.
Imagine standing in the middle of railway tracks which go off into the distance, and are perfectly straight for as far as you can see. If you look towards the distant horizon, where the tracks appear to converge to a point, that point is analogous to the meteor shower radiant, and the tracks themselves represent the paths (or orbits) of meteors. A meteor seen in the radiant would appear like a stationary star (or point of light - the important thing is that it's not a streak from your perspective) that suddenly appears, gets bright, and then dims, because it's heading directly towards you, just like a train coming down the track.
Meteors which start away from the radiant are no longer heading towards you, and perspective gives you a side on view of them, so if you go back to imagining yourself on the railway tracks, and if you turn through 90 degrees, you are now seeing the track from the side, which is like seeing a meteor at 90 degrees away from the radiant in the sky.
Now turn through another 90 degrees so that you are facing in the exact opposite direction that you started, and you are looking along a pair of tracks that converge on the horizon once again. Now you are looking at the anti-radiant, and meteors, following the path of the tracks actually seem to converge!
So all meteors seen @ 90 degrees from the radiant are seen side on, and guess what, they appear (and are!) parallel to each other. Perspective/foreshortening makes meteors seen anywhere else but 90 degrees from the radiant appear to either diverge or converge to a lesser or greater degree the further they are from 90 degrees.
It's actually all very simple if you think about it!
|