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Perseid fireball and spectrum

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BillW's picture
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Perseid fireball and spectrum

Hi,

After weeks of almost continuous cloud cover and some near biblical rain the sky cleared (well almost) right on cue for the Perseid peak! :-))

Captured 263 meteors on my various cameras and this...

Maybe around -4, but it's the spectrum at the bottom of the field that is truly exceptional!

Here's a crop..

.

Unfortunately it's only a partial spectrum but it is by far the highest resolution I have ever captured! The two brightest lines towards the top are the ionised calcium lines in the near UV.  The tiny terminal flare exhibits MANY emissions!

Cheers,

Bill.

A R Pratt's picture
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Perseid fireball and spectrum

Nice one, Bill !

My cameras were clouded out last night after midnight so unfortunately I can't contribute any data for this one. The perils of our long baseline. Looking forward to seeing your detailed spectrum after processing.

Weather prospects here look better for tonight.

Cheers,

     Alex.

BillW's picture
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Your wish is my command... ;-

Your wish is my command... ;-)

First is across the third "chop" back from the terminal flare.

Second is across the terminal flare. Ca+ saturated but lot's of metal lines light up. At least 35 lines (maybe a couple more) including the usual Mg, Ca and Fe but also Cr and Mn as well as possibly Ni.

Despite it's low efficiency, due to it's embossed profile, I'm really surprised (and pleased) with the performance of the plastic film. I'm becoming convinced that it does have slightly better properties in the UV/Blue compared to the expensive glass gratings.The results are evidence enough I think...

R is around 1000, not bad for such a basic transmission set up.

Going to leave a couple of glass ones on but change the rest to plastic and see how it goes over the next season.

The weather gods certainly gave me a break last night but I think we're in for more heavy showers tonight....

Cheers,

Bill.

A R Pratt's picture
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Perseid fireball and spectrum

You're resolving some fine details there Bill.

Fingers crossed for some mutual events tonight - but this weather system is spoiling the show.

Cheers,

     Alex.

BillW's picture
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Hi,

Hi,

Done some more work on the spectrum and the lines in the trail are coming out with a FWHM of around 1nm and the measured dispersion is 0.46nm/pix. It's now just about where I want to be. It seeing how all the little lines behave that tells the story...

Cheers,

Bill.

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Perseid fireball and spectrum

Excellent capture.  Digitised spectrum looks really good.

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Bill,

Bill,

Excellent spectra some good science there, well done.

Jack

Essex  

BillW's picture
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Hi,

Hi,

Thanks Jack.

It gets better....!

Whilst concentrating on the flare as it had so many lines I didn't really pay attention to the bright pair that ran close to the bottom of the image and through the camera ID text.

Taking a closer look revealed something remarkable. Since I started regular meteor spectroscopy around 2007 I've had the rather arbitrary goal of getting to a system that would resolve the bright green Mg triplet ~517nm. It's tough to do completely!

When I chopped up the image an fitted the lines it turns out that the "pair" is actually a partial resolution of the triplet! The 516.73nm and 517.27nm are just too close for this lens/grating/seeing combo but at the 1nm FWHM and 0.46nm/pix level it is just enough to see the 518.36nm line as separate, just over 1nm (2 pixels) between them. Here's a plot with the brighter lines identified.

Well pleased with that!

Cheers,

Bill.

BillW's picture
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ah ha, I knew I had a picture

ah ha, I knew I had a picture of the triplet some where....

The power of spectroscopy, the same elements but on the sun. I took this with a home made solar spectroscope, donkey's years ago, it shows the main Mg lines plus a ton of Fe, Cr and Ti lines. These'll be hiding in the meteor spectrum too!

Cheers,

Bill.