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前田
登録日: 2004.09.01 記事: 2759 所在地: Miyazai JAPAN (E131.4, N31.8)
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日時: Fri Dec 22, 2017 12:27 am 記事の件名: |
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Hi Martin,
Thank you for analyzing and uploading the modified fireball movie which is very stable. I like this type of movie due to find a detail structure.
Hi Bill,
The Geminid spectrum is interesting. The Na/Mg ratio of Geminid spectrum has often discussed in this Japanese forum, too. I think the distribution of the ratio is wide every year. I hope to analyze the statistical distribution of that ratio. I could not capture a fireball spectrum in this year, but I have obtained a lot of normal magnitude (-2 to 2 mag.) Geminid spectra.
Clear Skies,
Koji
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Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
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日時: Fri Dec 22, 2017 6:22 pm 記事の件名: |
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Hi,
The rest of the spectra I caught were in the range -2 to +2 also. They actually show some very interesting temporal effects on some lines.
I'll be writing up the results for the JBAA and WGN next year.
Now looking forward to the Quadrantids!
Cheers,
Bill.
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Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
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日時: Tue Jan 09, 2018 6:49 pm 記事の件名: |
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Hi,
Turns out that the Geminid spectrum looks great but isn't so useful due to some of the lines on the original being saturated
(However I have 8 that are useable. A lot more work than I anticipated, still ongoing...)
I put together a short youtube video showing the brightest fireball I captured during my Geminid excursion.
https://www.youtube.com/watch?v=LyXtSWLyhC0
Cheers,
Bill.
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tkuhmone
登録日: 2014.08.26 記事: 56
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日時: Wed Jan 10, 2018 10:08 pm 記事の件名: |
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thanks for providing material and video samples I might consider, also putting one my cameras with spectrum grating - when I update my station. I currently have two WAT910HX cameras...
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Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
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日時: Thu May 17, 2018 7:36 am 記事の件名: |
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Hi all,
Got some nice spectra during my Lyrid observing last month.
However I also captured a more unusual spectrum too.
Seems to have been a very slow moving meteor with no atmospheric emissions.
Very strong sodium emission and bright sodium trail (in the spectrum).
Nice bright emission from iron lines as well.
cheers,
Bill.
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Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
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前田
登録日: 2004.09.01 記事: 2759 所在地: Miyazai JAPAN (E131.4, N31.8)
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日時: Sat Oct 20, 2018 3:02 pm 記事の件名: |
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Hello Bill,
Thank you for your new spectrum.
Yes, the 777 nm line is so large. For a high-speed meteor, I think that the strength of 578nm line is weaker than 777nm line. Is this spectrum after sensitivity correction of the sensor?
By the way how about your Kilwinning Spectroscopic Survey for Meteors project afterwards? I remembered it to see the graph.
Clear Skies,
Koji
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Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
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日時: Sun Oct 21, 2018 2:16 am 記事の件名: |
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Hi,
In order to see the smaller features more clearly I have not corrected for detector sensitivity.
The 557.7nm line is prominent in the video because the forbidden transition takes ~2 seconds so lasts longer on the video that the rest of the spectrum features. In reality it is quite a weak emission.
My system is working well. I have recorded many spectra now (in the hundreds).
What I have discovered over the last 10 years is that the spectrum can actually give us a lot more information than just compositional data. The profile of the spectrum can give a lot of indirect information about the meteor even without being very detailed. This can be tied in with other observations. That has surprised me as I was not expecting it!
Regards,
Bill.
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前田
登録日: 2004.09.01 記事: 2759 所在地: Miyazai JAPAN (E131.4, N31.8)
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日時: Tue Oct 23, 2018 12:52 am 記事の件名: |
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Hi Bill,
Thank you for you reply. I also have analyzed without correction the sensitivity of detector at first.
I agree that the relationship between meteor spectra and light curves, orbits and et al. is very interesting.
I am looking forward to see what kind of things you have discovered from the many spectrum of the meteor that are known orbits.
Thank you,
Koji
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前田
登録日: 2004.09.01 記事: 2759 所在地: Miyazai JAPAN (E131.4, N31.8)
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日時: Sun Nov 11, 2018 11:47 am 記事の件名: a lucky image |
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Hi all,
I have captured a lucky image of meteor spectra, last night.
That is two meteors framed in one clip and crossed each other apparently.
Both meteors may be sporadic meteors.
Clear Skies,
Koji
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Martin Dubs
登録日: 2014.03.04 記事: 56
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日時: Sun Dec 02, 2018 6:09 am 記事の件名: |
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Hi Koji,
do you remember my analysis of a meteor spectrum about a year ago? http://sonotaco.jp/forum/viewtopic.php?t=3065&p=47795#47795
In the meantime I have worked on the processing. I combined the different programs for analysis into a single pipeline, written in Python. All processing steps are done within the same program. The processing pipeline allows to
- Extract the images from the video file
- Calculate the background image
- Subtract the background and apply the orthographic transformation
- Align the spectra and add them
- Make corrections for tilt and slant
- Convert the 2-d image to a 1-d spectrum
- Calibrate the spectrum with the known dispersion and several spectral lines
- Plot the final result.
The details of the processing are described here:
https://meteorspectroscopy.org/2018/11/18/meteor-spectraanalysed-with-python/
If you are interested, have a look there.
As an example of the results, here is the analysis of the spectrum mentioned above:
Since some images were saturated, the lines are broadened.
No instrument reponse correction applied, difficult for colour camera.
Clear Skies,
Martin
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first order spectrum calibrated, negative wavelength means first order on the wrong side of the grating |
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Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
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日時: Sun Dec 02, 2018 6:17 am 記事の件名: |
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Hi,
A year ago, time really flies. I can hardly believe this thread is now 6 years old!
That looks like great work. I'll have to read it carefully.
I need to buy myself a good book on python....
Cheers,
Bill.
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前田
登録日: 2004.09.01 記事: 2759 所在地: Miyazai JAPAN (E131.4, N31.8)
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日時: Thu Dec 13, 2018 10:38 pm 記事の件名: |
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Hi, Martin
Sorry for the late reply.
Of course, I will not forget you. You seem to have created a wonderful spectrum analysis software. I have no experience with Python, but I understood the flow of analysis by reading the manual. I think that it is efficient to input video files and handle them.
If I can master this program, I can analyze thousands of spectra, but for me it might be a high hurdle.
Thank you for introduction.
Regards,
Koji
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前田
登録日: 2004.09.01 記事: 2759 所在地: Miyazai JAPAN (E131.4, N31.8)
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日時: Sun Dec 16, 2018 9:48 pm 記事の件名: New system |
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Hi, all
I am testing a new monochrome spectrum camera system.
The video camera (DFK 33 GX 290 esc) with 1 / 2.8 inch CMOS sensor has 1920 x 1080 pixels
and attached 1.2 / 6 mm lens with 600 grooves / mm grating. The sensitivity is lower than SONY a7s system,
but this system is very small, then it can be easily put in a housing.
I tested this system for this Geminids. The Spectra could be taken with a brighter
meteor than mag. -1.
Clear Skies,
Koji
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Trimming near the spectrum
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Overall image (50 % shrinked) |
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Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
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日時: Thu Dec 27, 2018 4:11 am 記事の件名: |
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Hi Koji,
Looks a great system. I tried an Image Source camera a few years back but it was a tiny 1/4 inch chip with equally tiny pixels. I didn't catch anything with it!
What sensor is in your camera? I am planning on setting up a similar system with a ZWO camera next year.
Looking forward to seeing your results.
All the best for the new year.
Regards,
Bill.
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