A couple of good strong meteor detections last night. One clear and simple, and the other a little challenging to fully understand.
Here’s the simple one:
And this is the more challenging one:
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I set up an experiment this morning for the eta aquarid meteor shower to capture some meteor images and correlate them to infrasound signatures. Sounds simple, but I made some rookie mistakes… that’s OK, I’ve learned from them and maybe others will too if they plan to do a similar exercise.
The main thing is to aim the camera at zenith, NOT the radiant. I aimed at the radiant and as a result the meteors I imaged were a long way away, so the signals are very faint - perhaps too faint, and in some cases definitely too faint - and the infrasound travel times are quite large and subject to significant errors.
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Observing a bit far away from the radiant is advice that I often gave when observing meteor showers during some astronomical retreats I attended as a guide.
Even if all the pictures obviously include the radiant itself (especially the fisheye ones), one can see more meteors if the eyes are pointed some degrees away from it. With a camera like yours, I would put the radiant along one side, left or right depending on where the radiant is, and see what it captures in this way. I’m sure that with a couple of trials and errors you will be able to find the perfect position.
And the yearly meteor season is only starting!
Too cloudy again this morning for photos, so looked through the data and found this one that looked interesting. Resolved it into a three particle meteor, but suspect there could’ve been a 4th particle with a DSF of about 10Hz, but the signal was quite weak.
After 5 months learning and experimenting with meteor detection via infrasound, I thought it might be worth sharing what I’ve learned for anyone else considering doing this.
Infrasound detection won’t detect as many meteors as the traditional visual and photographic methods, simply because light from the meteor is not attenuated as much through the atmosphere. So the typical rates of detection I have found, are well below the expected hourly rates from visual methods. The best chance of detection is from meteors at zenith as this minimises the distance (50 to 100km) from the meteor to the RB/RSnB.
Bigger bolides and re-entering space junk are a different story though. Detection via infrasound is possible over distances far in excess of what’s possible visually or photographically. For example, I recently detected the re-entry of the SpaceX Dragon Crew 1 Trunk 370 kms away with my RSnB.
Advantages of infrasound detection of meteors is that it can detect close, large, fast meteors during daylight when visual methods can’t, and to a lesser extent when cloudy. The reason detection is reduced when cloudy is the the water droplets in the clouds absorb sound (including infrasound) in the same way the water sprays beneath the launchpad absorb dangerous levels of noise from the rocket during launch. Sound attenuation is also increased with increased humidity.
Rain and wind, unfortunately, produce a lot of infrasound, so noise levels in these conditions are raised reducing the chance of any detections.
Al.
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Very interesting. I have been doing radio detection of meteor trails for some years, using outdoor antennas and Software Defined Radios coupled with Argo recorder software. I never thought to correlate that with my S&B.
A great way to hear how radio meteor detection sounds is at https://www.livemeteors.com, which uses the same method I do.
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Thanks for all that.
Last year I posted some meteor booms that I caught.
I had been running meteor cameras that watch the sky all night and I was sharing data with two stations north of here. When a meteor trail entered the visual field of 2 or more cameras the software calculated the 3D trajectory of the meteor, the orbit it came from, the mass of the meteor. etc.
I believe that most meteors are too small to make a signal that can be detected by RBoom. But bolides - where there is a sudden disintegration of the meteor at lower altitudes - should be detectable. Most meteors that you see at night are somewhere between a spec of dust and a grain of sand. Its the bigger ones we are going to “hear”.
The American Meteor Society collects reports of bright meteors and fireballs (bolides) and if there are more than 5 reports of the same meteor lumps them into an “event”. (I have contributed a couple reports myself).
Fireball events (amsmeteors.org)
If there was an event near your RB, you should go back over the data and see if you can find it.
However, across the USA there are only a couple of fireballs each day on average. So you might need to wait awhile.
There are other meteor-watching networks as well and these will publish when fireballs have been detected.
www.fripon.org
Global Fireball Observatory: Home (gfo.rocks)
RMS | Global Meteor Network (istrastream.com)
etc
And of course if it rattles windows in populated areas it will be all over the popular press as well.
Happy hunting.
Ken
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