前のトピックを表示 :: 次のトピックを表示 |
投稿者 |
メッセージ |
Marian
登録日: 2015.10.12 記事: 8
|
日時: Sat Sep 03, 2016 3:37 am 記事の件名: |
|
|
Hello everybody! Hello Martin! (we have talked in the past year on e-mail,thanks for your help)
My name is Marian,I am from Ukraine,Ukrainian group video meteor observations.
This is my first spectrum.Camera Wat 902 H2 Ultimate,lens Rainbow H6X-8 17 15mm,10.2 A\pixel.I use IRIS and RSpec. Perseid -2.9m.
説明: |
|
ファイルサイズ: |
37.67 KB |
閲覧数: |
8487 回 |
|
説明: |
|
ファイルサイズ: |
65.23 KB |
閲覧数: |
8487 回 |
|
|
|
トップに戻る |
|
|
Martin Dubs
登録日: 2014.03.04 記事: 56
|
日時: Tue Sep 06, 2016 6:16 am 記事の件名: |
|
|
Hello Marian,
nice spectrum! Could you tell us a liittle more about how you analysed the spectrum. Did you use IRIS for the correction of dispersion as I described it (e.g. here: http://www.meteorastronomie.ch/spektroskopie.html)? The spectrum is well resolved and correctly assigned as far as I can tell. RSpec seems to do a good job.
Regards, Martin
|
|
トップに戻る |
|
|
Marian
登録日: 2015.10.12 記事: 8
|
日時: Tue Sep 06, 2016 6:41 pm 記事の件名: |
|
|
Yes,I use IRIS - Correct distortion.But I have many questions.I don't know how can I get
coefficients for my own camera.I use your coefficient,it helps a bit but not perfectly.
In RSpec I use non-linear calibration.Good visible lines help me to do it well - Mg 4481,Fe 5270,Na 5890,O 7774,second Order of Mg triplet...
説明: |
|
ファイルサイズ: |
190.57 KB |
閲覧数: |
8441 回 |
|
|
|
トップに戻る |
|
|
Marian
登録日: 2015.10.12 記事: 8
|
日時: Tue Sep 06, 2016 6:48 pm 記事の件名: |
|
|
If BillW do not mind - to compare my specturm and Bill's sporadic fireball
説明: |
|
ファイルサイズ: |
28.79 KB |
閲覧数: |
8438 回 |
|
|
|
トップに戻る |
|
|
Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
|
日時: Thu Sep 08, 2016 4:12 am 記事の件名: |
|
|
Hi Marian,
No problem, that is nice work!
It beautifully shows the real power of spectroscopy. We can now compare samples to each other which is something that could not be done easily in the past.
Normal integrated light observations just do not offer this possibility.
This has changed meteor observing completely in only a couple of years.
Cheers,
Bill.
|
|
トップに戻る |
|
|
Marian
登録日: 2015.10.12 記事: 8
|
日時: Tue Sep 13, 2016 7:36 am 記事の件名: |
|
|
Thanks Bill!
While I studied the Martin's "Processing meteor spectra" I caught another meteor.It is sporadic,-2.5m,order -1.I tried to identify famous lines
説明: |
|
ファイルサイズ: |
10.09 KB |
閲覧数: |
8351 回 |
|
説明: |
|
ファイルサイズ: |
25.56 KB |
閲覧数: |
8350 回 |
|
最終編集者 Marian [ Tue Sep 13, 2016 8:16 am ], 編集回数 1 回 |
|
トップに戻る |
|
|
Marian
登録日: 2015.10.12 記事: 8
|
日時: Tue Sep 13, 2016 8:13 am 記事の件名: |
|
|
I caught a spectra of Moon and compared it with those of my meteors .If I am right, I see telluric lines "B" 02,H2O, "A" O2 in all my spectra.It is not strange,but it is new for me.
説明: |
|
ファイルサイズ: |
12.53 KB |
閲覧数: |
8347 回 |
|
|
|
トップに戻る |
|
|
Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
|
日時: Tue Sep 20, 2016 5:31 am 記事の件名: |
|
|
Hi Marian,
The moon comparison is very good! Nicely shows the atmospheric absorption bands.
As another example of the power of spectroscopy, I had a close look at your spectrum again and I think your Perseid might not be a Perseid after all...
Your spectrum from the 2016 08 12 is really well dispersed but Perseids are fast moving meteors that tend to ablate higher up in the atmosphere. This gives them a distinct green colouration at the start as seen in photographic images. It comes from the 5577A (557.7nm) forbidden line of oxygen, the same colour that is seen in the aurora.
It is only seen above ~110km so it shows up as a distinct line at the start of the spectum and generally fades as the other lines brighten towards the end of the meteor. As the meteor travels lower into the atmosphere the emission from the forbidden O line gets "quenched" (in the jargon) and can no longer be seen.
If you examine your spectrum between the 517nm Mg line and the 589nm Na lines there is nothing distinct there so no forbidden O emission. So immediately we know it must either be an unusual Perseid as no 557.7nm line means it is travelling more slowly than your average Perseid and ablating lower in the atmosphere. Or it was not a Perseid and just had a co-incidental path.
An intriguing result and another illustration of the diagnostic fingerprinting we can now do.
cheers,
Bill.
|
|
トップに戻る |
|
|
Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
|
日時: Tue Sep 20, 2016 5:41 am 記事の件名: |
|
|
Hi again,
Attached is an image from an article I wrote explaining why we see the colours we do. (especially in images of Perseids, greenish at the start, through white then reddish at the end.)
You can see the faint but distinct 557.7nm line here which is missing from yours.
What I call "comparative meteor spectroscopy" is a very useful tool especially when there are limited observations as it can give us some clues to the speed and thus a guide to ablation height of the meteor.
Cheers,
Bill.
説明: |
|
ファイルサイズ: |
77.02 KB |
閲覧数: |
8285 回 |
|
|
|
トップに戻る |
|
|
Marian
登録日: 2015.10.12 記事: 8
|
日時: Tue Sep 20, 2016 10:47 pm 記事の件名: |
|
|
Hi Bill!
Thank you very much for interesting information.You are right,there is no distinct line 557.7 nm in my meteor.But UFO Orbit says - it is perseid.It has Vg 58.2 km,H1 113 km.this is for my part of analyze,but...Unfortunaly second station had problems with Fps on his camera at those days,so total quality for this meteor is only Qo.Therefore I can't be sure in my data.
説明: |
|
ファイルサイズ: |
112.85 KB |
閲覧数: |
8256 回 |
|
説明: |
|
ファイルサイズ: |
81.09 KB |
閲覧数: |
8255 回 |
|
|
|
トップに戻る |
|
|
Martin Dubs
登録日: 2014.03.04 記事: 56
|
日時: Wed Sep 21, 2016 7:03 am 記事の件名: |
|
|
Hi Bill and Marian,
I looked at my Perseid spectra from last year. I captured 3 Perseids with good orbits (meaasured by at least 4 stations). None of them showed the oxigen 557.7nm forbidden line. They were all bright (-4m to-6m), so I assume they evaporated at lower altitude than smaller meteors (starting height around 110 km, in one case 120 km, but spectrum only from later part of trail). In the enclosed document you find the spectra and notes on the processing and other information. In the meantime I have streamlined the pocessing somewhat. In one case I superimposed Bills spectrum with higher resolution, showing the 557.7nm line, absent in all my spectra. I cannot tell if this result is because of lower sensitivity of my images.
Marian, do you make any progress with my calibration method?
Regards, Martin
説明: |
processing log of 2015 Perseids |
|
ダウンロード |
ファイル名: |
Meteor spectra 201508Perseids.pdf |
ファイルサイズ: |
546.29 KB |
ダウンロード回数: |
266 回 |
|
|
トップに戻る |
|
|
Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
|
日時: Wed Sep 21, 2016 7:28 am 記事の件名: |
|
|
Hi,
The first two images in this thread were of extremely bright Perseids and they too don't show the 557.7nm lines.
Though the third does have it (faintly)
Maybe there is some critical cutoff of meteoroid brightness (mass) in combination with a given velocity that dictates how the particle behaves in the region above 110km.
Another interesting thing to explore.
Regards,
Bill.
|
|
トップに戻る |
|
|
Marian
登録日: 2015.10.12 記事: 8
|
日時: Fri Sep 23, 2016 2:04 am 記事の件名: |
|
|
Hi all!
Martin,I am still reading and thinking.
I have a question. I compared my solar spectrum and the spectra of meteors. The lines На аnd Hb look like the same. It is a coincidence or not?(Sun is red line,meteor is blue line).
説明: |
|
ファイルサイズ: |
19.93 KB |
閲覧数: |
8196 回 |
|
|
|
トップに戻る |
|
|
Bill W
登録日: 2012.02.13 記事: 182 所在地: Glasgow
|
日時: Tue Oct 04, 2016 2:40 am 記事の件名: |
|
|
Hi Marian,
That is a good question.
Ceratinly a lot of meteors show the Ha line at 656nm. But I don't know about Hb for certain.
Due to the resolution limits we work at and the noise in the images, sometimes lines can appear that aren't real.
There may well be a known line from some element at that wavelength but it is not a guarantee that it is really there from the meteor.
This is part of the challenge as we have no beforehand information about our "sample" and there are a lot of variables to take into consideration.
Maybe Martin or another observer can confirm Hb emission.
Cheers,
Bill.
|
|
トップに戻る |
|
|
前田
登録日: 2004.09.01 記事: 2759 所在地: Miyazai JAPAN (E131.4, N31.8)
|
日時: Fri Nov 25, 2016 10:45 pm 記事の件名: small fairball |
|
|
Hi all,
I captured a small fairball ( Mag. -2.5, dur. 1.7s ) tonight. It may belong Taurids.
In my location, it had been cloudy and rainy days in summer and autumn.
But it returned clear sky in winter !
Regards,
Koji
説明: |
SONY a7s + 24 mm + 600 grooves grating |
|
ファイルサイズ: |
76.51 KB |
閲覧数: |
7696 回 |
|
|
|
トップに戻る |
|
|
|