- This topic has 15 replies, 6 voices, and was last updated 1 month ago by
.
-
Posts
-
Hi all,
After a relatively quiet spell, there was a spectacular mag -9 fireball over central Scotland late on the 9th October
Due to the fall of the fireball and it’s brightness I captured an extremely high resolution 2nd order spectrum.
This is, by far, the most detailed video meteor spectrum ever captured.
Initial inspection reveals it to be a Type C with a very strong Sodium emission and the rest (mostly?) iron lines.
There are well over 145 lines in the 2nd order spectrum. Untangling the orders was very difficult and I’m not 100% certain that I’ve unpicked them all…
The spectrum plot is instrument corrected and the synthetic coloured spectrum is just remarkable!
Cheers,
Bill.Hi,
It looks like a sporadic in a low inclination orbit originating in the main asteroid belt.
Jamie produced some excellent analysis on the orbit and dark flight using multiple GMN cameras. I’ve sent these to Tracie for inclusion in the next TA.
Cheers,
Bill.Thanks Bill for sharing this tremendous observation. Certainly the best I’ve seen from the amateur community. I thought about comparing the spectrum with that recorded in Chile at the VLT FORS1 instrument taken in 2002 but sadly the two spectra are from different regions of the optical spectrum. So you may very well be correct that yours is the best so far obtained in that spectral range. See:
https://repository.arizona.edu/bitstream/handle/10150/656680/azu_meteoritics_v39_n4_609_616_m.pdf?sequence=1Hi.
It’s interesting you mention that paper in particular… I’ve used the spectra presented in that paper as a calibration starting point for many of my own!
I think elsewhere in my forum posts I actually show a comparison between my own set up, at the time, and the VLT one.Whilst mine was a lucky capture to be sure, the VLT one, given the field of view and size of slit was freaky lucky!
Bill.
Hi Richard,
I knew I had a recent spectrum from my HiReMS II system that had a comparable bit of Near IR spectrum.I have been lazy and just cropped the image rather than fully process it… but the pic spans the spectrum plots of fig 2 in in the paper (it just squeaks into the third…)
The main lines are easily identifiable.
Who needs the VLT….! ; – )))
Cheers,
Bill.Attachments:
Hi,
Returning to the fireball, Jamie has produced some graphics of the ground track and trajectory.I’ve added a “B” at my approximate location to show where the spectrum was captured from.
Thanks to all the GMN observers!
Cheers,
Bill.That’s a brilliant achievement Bill, congratulations. You should write this up for the Journal, or at least a short article about it.
Hi,
Thanks. I’ve only had two really good spectra captured in the 2nd and 3rd orders (one of which appears as the background image for some of the info banners on the BAA page!) so they are rare catches. This one was particularly luck because the Geocentric velocity was low, at just a shade over 21 km/sec. This meant that all the atmospheric lines that light up with faster entries were subdued. That was the only reason it was possible to produce any reasonable plot.
I’m hoping to extend my system with another camera later in the year. Once I get a couple of representative results then I’ll put something together for the Journal.
In the meantime a quick summary will be in the next(?) TA mag.
Cheers,
Bill.Great capture Bill.
Things have certainly moved on from my one (and only) attempt at this nearly 20 years ago
http://www.threehillsobservatory.co.uk/astro/spectra_20.htmHi,
I also used to correspond with Ed, I don’t know if you’re aware but Ed died last year. I only found out myself earlier this year after emailing some other Canadian collegues. He was always very encouraging, he persuaded me to persevere after decades of nothing on film. We dicussed the merits of film vs the emerging digital technologies as I had bought my first watec in 2005 too. It was Ed who mentioned your page in our musings.
The methods are as old as they come, it’s the detector technology that has evolved quickly. I’m surprised myself how good the reults can be if fortune places a nice meteor in the field of view.
Looking forward to more!
Bill.
Hi,
A re-work of the synthetic spectrum. From ~430nm to 591nm
Cheers,
Bill.Attachments:
Hi Jack,
Thanks, the software I use is IRIS for the geometetric corections and Visual Spec for the spectroscopy. Both free packages and I’ve been using them from nearly 20 years!
There are now probably more modern software options avaialable but as I do the “fitting” manually these work well for me.
Cheers,
Bill.Hi,
Caught another Type C last night. This is a much more regular capture… a partial spectrum and in the first order only.
Doesn’t quite cover the same span as the super high resolution one, ~427nm to 592nm, but it’s interesting to see the how all the extra lines emerge between the usual “strong” lines.
Cheers,
Bill.Attachments:
- You must be logged in to reply to this topic.