开云体育

Hi all, Did anyone record a SID yesterday (20th April) at 19:00? There wasn't an Xray flare from the Sun at that time, but I recorded a SID as shown on the plot but only on 3 out of the 8 freqs. I monitor. There was a glitch in the mag field recorded on the Mull magnetometer at the same time, but not a very strong one. Very curious. It doesn't seem to be a GRB as I couldn't find one recorded yesterday. Any ideas? Cheers, Mark

My magnetometer shows a slight disturbance from about 1900 UT onwards. -- Roger Blackwell GM4PMK www.marsport.org.uk

I am looking for volunteers to assist with the VLF data repository project. The repository is a collection of 27,000 VLF data files currently held at https://vlfdata.org/. The project has been in abeyance for the last couple of years and I am hoping to breathe some life back into it. The key tasks for which I would like to recruit helpers are: A contributor liaison person. No technical skills are needed for this role. Stage 1 will involve (re-) establishing contact with past contributors to the project, finding out whether they are still willing to contribute their data and arranging for the data files to be submitted. Stage 2 will involve contacting other potential contributors and arranging for their data files to be submitted. A data transfer person. This role needs someone with skills in data transfer (ftp?). In the past, data files have been contributed by post/data stick/CD on an annual basis. It would be preferable for this process to be automated on, perhaps, a monthly basis. A data processing person. This role needs someone with scripting/programming skills. Data files are submitted in various formats (*.csv, *.txt, *.spd etc) with file names created by the contributor. The files need to be processed so as to firstly translate non csv files into csv format, secondly translate the file names into a standard format and thirdly to upload the files to the website data store. Scripts/programs have already been written to handle these tasks, but these need to be tweaked where necessary eg where a new contributor submits files. The scripts/programs also need to be run when new files are submitted by contributors. A data standardisation person. This role needs someone with VLF data experience and who is familiar with metadata. The value of the data files is dependent on the accompanying data submitted by contributors. To take a trivial example a data file has little, if any, value if the data entries are not time stamped or if the observation frequency is not known. Contributors are not consistent in the amount of metadata which they provide, nor in whether they include that metadata within the data files or elsewhere (eg in a covering letter). There is scope for increasing the value of the data by standardising the metadata collected and how it is stored. A research facilitator. This role needs someone with VLF data experience and some familiarity with academic research would be a bonus. There is little point in collecting data if it is not going to be used. We have identified a number of potential research topics and need to match those up with researchers, either from the amateur astronomy community or from academia with a view to the results of the research being published. A website manager. The present website is dated and needs a revamp Someone who is adept at MySQL or similar. At present the data is not at all easy to use and you have to slog through the date folders to see if what you want is there and then extract each file one by one. We would like to have a simple GUI between the user and the data which does all of the hard work, enabling a researcher to pull out all of the files from, for example, a specified observer at a specified frequency on specified dates. Some of these roles overlap. If you think that you may be able to assist, or if you need any further information, please let me know. Andrew Lutley

Still lots of interesting echoes at https://ukmeteorbeacon.org/beaconclient/ showing Doppler, directional and polarisation characteristics.

Andrew Thornett will present his home observatory including H-line observations and remote access at Green Bank. Richard Knott will present Muon detector... – the next step forward. This will include instrumentation and software for data analysis and presentation. If you are not on the distribution list, please contact me for the Zoom link. -- ??? Paul Hearn ?? paul@... ?? RA Section Director ??

I wanted to share my sigh of relief as I complete the latest stage in my development of radio meteor detection and analysis. I think that radio meteor observers probably all interested in knowing where the meteoroids were located. This was the motivation for this line of research. The culmination of work so far is a map showing the full extent of my detection range so far. The basis of the analysis is matching radio events with video events. This is not just a matter of matching times between the two sets of data but crucially employing a fundamental property of radio scatter that I refer to as the Point of Closest Approach (PCA). As a meteoroid moves along its trajectory, the total distance between transmitter to meteor and meteor to receiver changes. If this total distance passes through a minimum distance the trajectory has passed through a Point of Closest Approach. This point in space corresponds to where the “Head Echo” becomes the specular reflection trail. I used the GMN video camera meteor network to provide start and end locations for all of the resolved meteor detections during August 2024 (yes it’s taken me that long) and calculated the PCAs for the GRAVES transmitter in France and my Hayfield location. I have plotted the positions of the video PCAs with matching times with my radio events with head echoes on the azimuth-range map. As expected I found events beyond the GRAVES transmitter with the furthest radio detection some 1000km from Hayfield corresponding to a meteor from the August omicron Aquariids stream. For a rough idea of the numbers, there were just over 30,000 GMN events, 4500 radio echo events with 350 having head echoes and matching PCA and time. Mike German, Hayfield, UK

The UK Meteor Radar project is operational with the beacon transmitter at the Sherwood observatory, and 5 receivers at four locations with their antennas beaming into the common volume above the beacon to create a bi static radar system. Live data from all the operational receivers can be viewed at https://ukmeteorbeacon.org/beaconclient/ and guidance on how to recognise meteor echoes, aircraft echoes, interference and other phenomena can be found at https://ukmeteorbeacon.org/Livedisplay . The best time to look is in the first half of the day UK local time when you can expect to see meteor echoes at a rate of 2 to 3 per minute. With the high resolution of Doppler shift offered by the live display you can expect to see some exotic echoes like this one seen only by the Blairgowrie receiver. Brian

Sudden Ionospheric Disturbances are changes in power level of very low frequency signals detected with simple equipment in our houses that take up very little space and represent the changes in the atmosphere of Earth in response to solar flare events on the sun. Here is a recent trace from LRO – if you have never monitored SIDs then I can highly recommend it – cheap, easy, very effective and does not require Einsteinian intellectual abilities to understand (at least not the way I understand it, anyway! Andy

Hi All, I have tried peeling off the Mylar coating on two of the petals on my solar cooker parabolic reflector – and they do come off easily as per attached photos. Andy

Some interesting echoes this morning. The UK Meteor Radar project has now started recording the full bandwidth data from all the receivers in the network for development and research purposes. An archive of these recordings can be found at https://ukmeteorbeacon.org/LivestreamRecordingsList Brian