Meteor spectroscopy of fireball
Posted: Thu Jul 23, 2015 8:25 pm
Hello,
I would like to present some recent results on a topic not regularly covered here. Yesterday a bright (-8mag) fireball was observed in Switzerland by several stations of the Swiss Meteor Network (Fachgruppe Meteorastronomie). From the same meteor visual, photographic, video, radio and spectroscopic mesurements were obtained simultaneously. From these observations the flight path could be reconstructed. If it had not exploded high up in the atmosphere, it would have landed close to one of the observers for easy collection. Details you can find here:
http://www.meteorastronomie.ch/ergebnisse.html
The results on the spectroscopy of this meteor and video spectrum you find further down on the page. I analyzed the beginning of the meteor spectrum by registering and stacking 8 video fields (160ms total exposure)
and the stationary afterglow by adding 7 video fields.
The brightest part of the meteor recording was completely overexposed, not suitable for analysis.
I may add that the spectra were linearized before stacking with a new method described here (basically a transformation of the video images to an orthographic projection):
http://www.meteorastronomie.ch/images/M ... _part2.pdf
This is important for spectra recorded with a wide angle camera, dispersion is dependent on meteor position.
Further processing (stacking, correction of slant, addition of rows etc. as well as extracting the images from the video, background subtraction etc.) was done in IRIS, plotting in ISIS.
The analyzed spectra (not corrected for instrument response) show large differences, with the O I line at 7774A missing in the afterglow and the intensities of the Mg I (5178) and Na I (5890) reversed in the two spectra.
The forest of lines around 4000A has not been fully identified (Fe, Mg, Ca):
Regards, Martin
I would like to present some recent results on a topic not regularly covered here. Yesterday a bright (-8mag) fireball was observed in Switzerland by several stations of the Swiss Meteor Network (Fachgruppe Meteorastronomie). From the same meteor visual, photographic, video, radio and spectroscopic mesurements were obtained simultaneously. From these observations the flight path could be reconstructed. If it had not exploded high up in the atmosphere, it would have landed close to one of the observers for easy collection. Details you can find here:
http://www.meteorastronomie.ch/ergebnisse.html
The results on the spectroscopy of this meteor and video spectrum you find further down on the page. I analyzed the beginning of the meteor spectrum by registering and stacking 8 video fields (160ms total exposure)
- stacked spectrum of beginning
- 150722a8.jpg (38.02 KiB) Viewed 4520 times
- raw spectrum of trail
- trailadd7.jpg (18.79 KiB) Viewed 4520 times
I may add that the spectra were linearized before stacking with a new method described here (basically a transformation of the video images to an orthographic projection):
http://www.meteorastronomie.ch/images/M ... _part2.pdf
This is important for spectra recorded with a wide angle camera, dispersion is dependent on meteor position.
Further processing (stacking, correction of slant, addition of rows etc. as well as extracting the images from the video, background subtraction etc.) was done in IRIS, plotting in ISIS.
The analyzed spectra (not corrected for instrument response) show large differences, with the O I line at 7774A missing in the afterglow and the intensities of the Mg I (5178) and Na I (5890) reversed in the two spectra.
- comparison beginning and trail
- 150722a8-trail.png (8.35 KiB) Viewed 4520 times
- zoom on spectrum of beginning
- 150722a8cal2d2.png (5.49 KiB) Viewed 4520 times
. We need still larger format camera sensors to match the resolution and capture area of film cameras though. I still dream of running a large format CCD camera with a nice wide field APO lens and an objective grating continuously with short exposures every clear night. I just need someone to buy it for me 