SonotaCo.JP

[前田]

Hi Bill,
Good results.

This spectrum is nice resolution and a characteristic spectrum. Is your camera a SD resolution ?
The spectrum is Na rich type ? It looks Mg free meteoroids which type is not general, I think.

Regards,
Koji

[Bill W]

Hi,

Yes SD, its just a WATEC 910HX/RC with a 12mm f0.8 plus a 830grooves/mm grating.
I was lucky that the meteor crossed the grating almost perfectly so got good detail.

The Magnesium lines is just a bit stronger than Sodium on this one. It is interesting to compare this sporadic to the Quadrantids.

Last year I caught several QUA's that showed very distinct Sodium "deficiency" compared to Magnesium. This was confirmed this year. (details https://britastro.org/node/7066 )

Cheers,
Bill.

[前田]

Hi Bill
I mistook the last message. The spectrum has a intence Mg line !
I understood just after reading your comments, thank you.

Yes, I agree about the QUA spectrum images. They has unique light curve of Na line against Mg line.
I uploaded the this year's QUA ( and COM) spectra in the following Japanese board.

http://sonotaco.jp/forum/viewtopic.php?t=3522&start=15

Cheers,
Koji

[Bill W]

Hi Koji,

Your QUA video results are really good. It's nice to see a real colour image with the green line much stronger than the yellow sodium line.

What camera and lens do you use to make these images?

Cheers,
Bill.

[前田]

Hi Bill and everyone,

I introduce my system. I have two high definition video systems controlled by UFOCaptureHD..

1. main
camera: SONY alpha 7s, 4K 30p mode
lens: Canon FD24mmF1.4L (sometimes FD50mmF1.4)
grating: 600 Grooves / mm, UV, Edmund opt.

2. sub
camera: Canon EOS6D, HD 30p mode
lens: Sigma 35mmF1.4
grating: 600 Grooves / mm, UV or 600 Grooves / mm, VIS, Edmund opt.

QUA spectra are captured by main system.

Regards,
Koji

addition the camera photos on 2016　Jan. 16

[Bill W]

Hi All,

Yesterday morning gave two spectra. Although both were "complete" in wavelength span terms, the first was very faint and I couldn't extract anything useful from it.
However the second turned out to be very interesting!

It took a few iterations to get the lines to fit what I think is reality. What surprised me is this particular meteor is VERY sodium deficient. There is a lot in the literature about sodium deficient meteors but this is the first I've seen with essentially none visible in the spectrum (there is indeed a small line at the sodium wavelength, ~589nm, but it's very weak and may be something else). A lot of the other small scale "peaks" can be made to fit anything but these are processing artifacts from the interline scan when the image was being "de-slanted".

A really interesting capture which I think re-enforces my idea that with long term regular monitoring it will be the sporadic population that throws up the most interesting results!

cheers,
Bill.

PS. Orbit still to be determined but thanks to the guys in the Nemetode group, who also captured the meteor, this will be posted shortly.

[Bill W]

Hi,

I captured a nice meteor of the morning of 18/2/16 with one of my 830g/mm cameras.
To my surprise I got it in the second order (and possibly a bit of the third) which gives remarkable resolution! It spans approx 480nm to 600nm with a dispersion of less than 0.4nm/pix.
I think this might be the highest resolution VIDEO meteor spectrum ever recorded.
The problem is I can't get a full match with known lines. There may be some issues with optical distortion I'm not fully accounting for but its frustrating not be be able to say for sure exactly what all the lines are.
So rather than a graph I've made up a colourised version just to illustrate the good resolution. If nothing else it shows what can be achived now with a bit of luck.

Cheers,
Bill.

[Bill W]

Hi,

Here's a quick look at how things have improved over the last few years in my observing programme.

https://youtu.be/milJHQat4q8

Cheers,
Bill.

[前田]

Hi,
I uploaded the visual meteor spectral catalog in 2015 captured by 4K video. There are various kinds of spectra. Almost meteors have faint spectra, but some bright spectra are very beautiful. The spectra are roughly classified in a list by the naked eye.

http://sonotaco.jp/forum/viewtopic.php?t=3650

Thank you,
Koji

[Bill W]

Hi Koji,
These are fantastic results!
I wish I could record as many.
Some are truly beautiful and the ones where you have captured the 2nd and 3rd orders are wonderfully detailed.
My favourite is EO250 with it's great flare spectrum.
Cheers,
Bill.

[Martin Dubs]

Hi Koji,

a long time ago I promised you an analysis of the magnitude of the beautiful and quite rare iron meteor of 20160107, see here: http://sonotaco.jp/forum/files/m20160107_225526_jpmz1_hdpc_826.jpg

I used the spectrum of alpCMa (visible at the top) for calibration (converting pixel sums to magnitude with a constant calibration factor) and analyzed this spectrum and the meteor spectra of all the images separately after flat field correction and linearizing the spectra with my special method (orthographic projection). The instrument response function from the color images looked a bit noisy, but I extracted V-mag by multiplying the calibrated spectra with a Bessell weight function for visual magnitude and integrating (summing) the resulting spectrum. This worked quite well but the 1st oder spectrum saturated so I also used the 2nd order spectrum to determine the luminosity of the brighter part of the meteor spectrum. At the moment there are some manual steps involved, so the procedure is quite time consuming, but by now I have all the calibration steps together (wavelength calibration and flux calibration), so we could start producing well calibrated spectra.

The first order spectra saturated at about -4.5m, the second order indicated a brightness of approx. -5.5m. Unlike other light curves the luminosity varied quite smoothly, which can already be guessed from the original peak image.

Thank you Koji for sending me all the required calibration files (laser wavelength calibration, flat, dark etc). Next weekend I will present some results at the the Swiss meteor meeting.

Best regards, Martin

[前田]

Hi Martin,
Thank you for your calibration and analysis to the spectrum. I almost understand the
story of analysis. I don’t know about a Bessell weight function. I think the results graph of the mag. is reasonable. You have spent much time, thank you very much.

regards,
Koji

[geosweiningen]

Dear Koji

Thank you very much for introducing your system here.

I'm also going to build me a 4K equipment to use it, amongst other, for spectroscopy. I have procured a Sony a7s II and at ebay the Canon FD24mmF1.4L lens.

For me the lens is vignetting very strong and I think it is probably because of the distance caused by the lens adapter. I use this one: http://www.bhphotovideo.com/c/product/1049193-REG/metabones_mbfd_e_bm1_canon_fd_mount_lens.html

Do you maybe have the same situation or could you tell me what you are using for an adapter ring for the lens?

Thank you very much for your feedback.

Best Regards,
Roger

[前田]

Dear Roger,

Yes, I use a Canon FD to NEX mount adapter. That is a conventional one.
I bought from a Japanese shop.
http://store.shopping.yahoo.co.jp/hassendo/c-f-e-02.html

I expect to get better images for your new SONY camera.

By the way, I cast a quick glance at your homepage. Your infrasound observation is very interesting. I hope to detect infrasound from meteor in a far future.

Regards,
Koji

[geosweiningen]

Dear Koji

Thank you very much for your answer and the link! I’ll try to get it.

Homepage: Thanks for visiting. It’s still ‘under construction’. I make first tests with infrasound. I detected already storms, helicopter, lightning strikes and the local postbus . But no meteor so far.

It’s hard to filter out the signal from background noise or local disturbances. I think it’s quite hard to detect a meteor with only one station.

A seismic detection of a meteor I already made but I needed additionally data from nearby seismographs of the Swiss Seismological Service to confirm the very weak signal in my data.

So we are discussing a low-cost infrasound network with several stations in our group.
Currently we have a closer look to this project here: http://michaelfranzl.com/2015/05/20/spectral-fft-infrasound-barograph-arduino-uno-bosch-bmp180-qt5-html5/

What kind of infrasound detector do you use?

Best Regards,

Roger