Very large meteor-like event detected 09:20 UT, 19/03/18

[Orion]

My 24/7 radio meteor monitoring system at Loughborough using GRAVES radar 143.048 MHz detected this very large event lasting nearly two minutes, at 09:20 UT on the morning of 19 March 2018.  I've not recorded one as long since last summer when the system went operational.   It's not unknown for bright meteors or fireballs to leave "smoke" trails that can last for seconds to minutes after the main trail has taken place. This is due to lasting ionised plasma left behind which drifts.  It could continue to reflect radio signals from it and be detected by a receiver.  Alternative theories are that this event may have been due to re-entry of space debris or a satellite.  I don't know which organisations would know for sure of whether any re-entries (planned or non-planned) has occurred at this particular time and date. Does anyone know? There are some websites which show planned and non planned re-entries but I couldn't find one for 19/3/18, though I haven't looked since 20/3/18.

 

The exact time of the start is taken from the beginning of the bright pattern.  Would anyone like to help me in the search for what this could have been due to (other than a daylight meteor)?  Duration was detected as 107.7 seconds.

 

 

[+Graham]

Fascinating stuff. 

[Tweedledee]

Great stuff. That would probably have been a really spectacular sight if it had occurred at night time. 

[Smithysteve]

Very interesting stuff - i hope you do not mind, but i have forwarded your info onto our observatory radio astronomy director to see if he was aware of same - we also monitor the Graves etc. it would be interesting if we can see the data from the Mansfield area - perhaps triangulate data etc.

Cheers! 

Edited March 23, 2018 by Smithysteve

[Orion]

That's fine Steve.   I don't know of a triangulation method for radio observations, but if there is one, I wouldn't mind finding what can be done.  The triangulation method is known for visual observations where the apparent position is taken from the background star grid for each location.  It would be great if something could be done for radio detections.  If some locations didn't detect an event and some do, some geometrical arrangements of the radar pulse shape and extent in space, the position of a meteor (or rocket re-entry) and the relative locations of the observing stations must have some mathematical relationship.  

[Tweedledee]

9 hours ago, Orion said:

That's fine Steve.   I don't know of a triangulation method for radio observations, but if there is one, I wouldn't mind finding what can be done.  The triangulation method is known for visual observations where the apparent position is taken from the background star grid for each location.  It would be great if something could be done for radio detections.  If some locations didn't detect an event and some do, some geometrical arrangements of the radar pulse shape and extent in space, the position of a meteor (or rocket re-entry) and the relative locations of the observing stations must have some mathematical relationship.  

As far as I know meteorites have actually been located on the ground by triangulating radar data to within an accuracy of a kilometre or two. So I'm sure that a reasonable estimate of both position and direction of travel could be mathematically derived from several sets of radar measurements from amateur meteor radar equipment.

[Orion]

Very interesting.  I'd like to use that to find a meteorite (as long as it isn't a really big one).

[Tweedledee]

14 minutes ago, Orion said:

Very interesting.  I'd like to use that to find a meteorite (as long as it isn't a really big one).

A 2 kilometre meteorite might destroy your radar, among other things.  

[Smithysteve]

I would like to know a bit more about your setup Derek. No doubt others would be interested too.

Aierial, amplifier, software, pc, The Graves transmitter etc.

Do you record data continuously, trawl through it or receive notifications?

Perhaps you should consider starting a thread on your setup. If not, perhaps you could pm me.

cheers! ?

[Orion]

I made the aerial according to the instructions in the Sky at Night Magazine article by Paul Hyde, on the BAA web site here:

http://www.britastro.org/radio/downloads/SkyAtNight/BBC_SatN_HOWTOOBSERVEMETEORS.pdf

Aerial type. 3 element Yagi, single dipole. Made of 15mm copper water/gas pipe. Pointing South East towards France; elevation approx... 10 degrees.

 

Amplifier. Funcube dongle £150 (new)  - set at 143.048 MHz (GRAVES). Each Funcube dongle is different and requires an offset to be determined by tuning into a beacon of known frequency – e.g. the Trent Beacon.  Then looking at the actual frequency measured. The difference is the offset that is applied to the Spectrum Labs software in order to run at the desired GRAVES frequency exactly (something like that).

 

Software. Spectrum Labs (free).

Funcube dongle software (free).

Paul Hyde’s script for Spectrum Labs which interprets the data for “events” which consist of meteors, moon bounce, interference, and produces a daily log file as a text file, which contain comma separated variable and can be used for further analysis.

The script also produces a screen grab every 5 minutes every day = 288 screen shots/day. It is easy to scroll through them for significant bright events, by flicking through thumb nails in File Explorer.  A day’s screenshots can be viewed in a few minutes.

 

PC. Dedicated Dell Optiplex 760 Pentium 4 HT 2.8GHz 80GB / 2GB. Windows 7.

HP Pavillion 23xi 23" Flatscreen Monitor

GRAVES transmitter.  143.048 MHz.

 

Data are recorded continuously 24/7.  It becomes an interest before or after breakfast to flick through the data to see what you’ve recorded the previous night (when it was pouring of rain).

 

The data recorded are not all meteors, but contains other disturbances that cause detections of events.  Meteor events are often characteristic shapes, so easy enough to recognise.  But if you wanted to do quantitative analysis, the data has to be stripped of non-meteor events, which can be tricky and is not automated.  We need some way of automatically identifying true events from all events recorded.  Currently, I just record the data.

Aerial close up

Edited March 24, 2018 by Orion
Addition of operating system; Windows 7

[Smithysteve]

Excellent Derek, great write up. ?

up at my local Obs, it is surprising how exciting a ping can be when you look at live meteors streaming in over the channel etc. You never know what you are going to get, but there are so many coming in especially during a meteor shower ? it’s all quite a buzz!?

[Orion]

Yes. I'm relatively new to radio astronomy.  I was shown how to hear the pings amongst an awful noisy background. I don't know if that can be toned down and cleaned up so it is pleasant to hear the pings in the absence of the noise.  I assume it is possible, such as removing the noise from an area where there is no signal.  When I was shown briefly how to listen to the pings, I think Spectrum Labs had to be configured a different way, so it was a choice of either/or, and once heard, the novelty, I was told, would wear off.  It was possible to record the WAV files, but again, I have forgotten how to that, and the data size/day may be overly massive to manage.  There was some discussion last year at a BAA radio astronomy group meeting about WAV files being of potential use in analysis and identification, particularly the information in the head echo.

 

  It's still totally clouded out here, but the radio detector continues to show meteors coming in.  When you said about them coming in over the channel, is there a way to know where they are coming from? I know we discussed earlier possible triangulation.

 

Enjoy your night at the observatory.

[Smithysteve]

We are new to it too Derek,

here is a link to our website, click on the radio astronomy tab and you will see in the 2017 report etc. where we are at.

you do not need to log in etc.

https://sherwood-observatory.org.uk/radio-astronomy/introduction

cheers!

[Orion]

Thanks Steve for the link. It sounds like you're further than me certainly.  The story of the chap in Spain rings a bell - I have a feeling I read something similar when I was reading up on different web sites.  I don't know what the difference is in Back Scatter and Forward Scatter methods of meteor detection.  I'm interested in how you monitor solar activity too.   At some stage, perhaps I can visit you at the observatory.

[Smithysteve]

Did you read the 2017 report on progress, diagrams etc Derek? See here:

https://sherwood-observatory.org.uk/radio-astronomy/yearly-reports/2017

i will let you know if anything is happening, events etc. and have a word with ‘sparky’ about your interest, then perhaps a visit would be worth your while at some convenient point. We are installing a fish eye camera to capture visual data, we will then try and line it up with the radio data.

i will pm you after I have made some enquiries ?

[Smithysteve]

2 hours ago, Orion said:

 I don't know what the difference is in Back Scatter and Forward Scatter methods of meteor detection.  I'm interested in how you monitor solar activity too.   At some stage, perhaps I can visit you at the observatory.

Have you seen this useful info on the GRAVES transmitter?

 https://www.britastro.org/radio/projects/MeteorRadarSDRReceiver.pdf

you will why this one is back scatter, (the Brams is forward scatter)

cheers!

 

[Orion]

I hadn't realised that there was more in the sub menus so looked at that briefly on screen (but can't read well on screen for too much - prefer to read from print, and ideally a file that can be printed rather than a web page).

I'll have a look at the info on GRAVES.  Thanks.

[Orion]

Yes, I've got that paper by David Morgan. It's excellent.

[Orion]

Steve.  You may find this link of interest.  It was sent to me today.

 

http://www.retram.org/

 

 

[Smithysteve]

 

13 hours ago, Orion said:

Steve.  You may find this link of interest.  It was sent to me today.

 

http://www.retram.org/

 

 

Thanks Derek, lots of great info on that site, ? will have a good trawl through it later. 

I have been having a look at the aerial build and FUNcube pro + etc. To see what’s involved... 

Regards our astro club: We are going to try to set up our radio astro stuff so that members can log in to our systems from home, so that might be enough for now. But I am starting to get a keen interest in this field, at least the clouds don’t get in the way...

Also, ‘Sparky’, our clubs radio Astro guru, had a look at your capture and said ‘WOW!’. He thinks it could be space debris due to its apparent low speed. I will have a chat with him when I see him next...

cheers!

[Orion]

Oh thanks for that.  How can you tell what the speed is?  Presumably the clues are in the Doppler number, or decibel signal? I don't understand them well enough and need examples of a range of signal values to be able to spot (from values) what's weak, low velocity etc. 

[Smithysteve]

i may see him tonight, if not i will ask him via an email etc.

[Smithysteve]

My Astrobuddy Nigel responded with the following...

” With regard to your questions, and I think its great that you ask them, I would just like to say that I dont consider myself as a knowledgeable person in this field, but what I have learnt since joining the RA section, is that meteors enter our atmosphere at a variety of speeds depending on:-

 

The orientation of the earth

The angle at which the parent comet / asteroid crosses our path

Or indeed whether it is in a retrograde orbit

This is in respect of meteor showers. Sporadic meteors can come from anywhere, some are from old long forgotten shows that have petered away to indecipherable singles. 

But according to the American Meteor Society - Meteors enter the atmosphere at speeds ranging from 11 km/sec (25,000 mph), to 72 km/sec (160,000 mph!).

Because meteors are made up of solid rock or metal their surface area to mass ratio is small and hence their drag in the air is small. Heating effects are quite sudden and they burn up quickly. Larger ones have even a lower ratio and are even less effected by the air and are more then likely to explode, this would lead to multiple traces. Its not often you get a head reflection, most of the time it comes from the plasma trail, or more precisely the electrons in it. The plasma trail is made up of not only electrons but the positively charged nuclei from the atoms they were created from and would soon reconfiger back to neutral atoms. The winds at that altitude tend to brake up the trails and you can get multiple pings but they are only short lived.

 

Now with respect to space junk. Low earth orbiting satellites / junk have a speed of around 7.8 km/sec (17,500 mph). A much slower speed. Their surface to mass ratio is much greater then meteors hence they are slowed much quicker at around 10g. Most of the insides are just space eg empty fuel tanks etc. These would probably explode and spread debre wider and slow even more giving a much more spread out reflection lasting much longer.

I watched the video footage of the NASA's Compton Gamma Ray Observatory burning up in the atmosphere and the duration was somewhat over 1 1/2 minutes. It showed multiple fragments as it broke up.

 

So my bet is it being space junk. But I could be wrong!

 

Your other points, we have been using the Funcube dongle pro + for some time now, and is the main receiver for meteor observations. On saying that we also have a number of other ones as well.

 

With regard to detecting the speed and motion of the meteor, it is best that you triangulate with other observers. It is then possible to determine its trajectory from its doppler shift, or so i've been told.”

Regards, Nigel

 

thought you might find it interesting.

steve

[Orion]

Thanks for that reply Steve.  It would be nice at some stage to go over those situations on paper to learn the graphic that would be seen (for my learning).

[Bottletopburly]

All on testing stuff  way over my head , if you’re ever in Devon a trip to the Norman Lockyer observatory is worth a visit nice set up ,   there’s a chap there for the life of me can’t remember his name John somebody  , he is on Twitter used followed him ( ditched Twitter) 

http://normanlockyer.com/astronomy-group/radio-astronomy/

Edited May 15, 2018 by Bottletopburly