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Perseid meteor


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About this observation
Nick James
Time of observation
14/08/2018 - 02:59
Perseid meteor
Observing location
Chelmsford, UK
Sony A7s, Canon 85mm, f/1.2L
1/25s at ISO 60000
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These are frames from a 25fps video. Each frame has an exposure of 1/25s and you get to see a lot more of what is happening to the meteor as it burns up compared to a B&W video or still image. The stellar limiting mag in video frames with this system is around 9.5. The green line behind the vaporizing meteoroid comes from neutral oxygen emission high in the atmosphere. This is visible for several seconds after the event and it is affected by high altitude winds. Some video of example events taken with this system during this year's Perseids is here.


Jeremy's picture

Interesting colour meteors, Nick. They seem to change rapidly from green to white, but looks like other colours appear during the transition. Is there any way to extract that colour data or make it more obvious?

nickjames's picture

I've put a frame by frame video of this meteor here. To give some context the field of view is 8 x 6 deg. The bright star just above the trail is 39 Ari which is mag 4.5. The reddish "head" of the meteor is the meteoroid ablating in the atmosphere. This is a point source smeared out by the 1/25 s exposure. At its brightest this is saturating the detector so it looks white. The only other colour I can see is the strong green neutral oxygen emission at 557.7nm. In frame 00:23:02:06 we see the last trace of the meteoroid as a fading reddish streak with the bright green train starting to drift and distort behind.

Jeremy's picture

Thanks for the frame by frame video, Nick. It does make it easier to see what's going on, but as you say it's saturating to white.


Peter Carson's picture

I'm really impressed with those videos showing the winds distorting the meteor trains. I've seen several twisting trains visually but never ones that distorted so quickly.

nickjames's picture

Yes, I guess you could work out the wind speed knowing the resolution of the camera and the distance to the train. I think the winds at 60-80km are around 100 m/s or so.

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