Dunsink Lane, Castleknock, Dublin 15, D15 XR2R dunsink@dias.ie

Meteors and Observations from Dunsink

Bright fireball seen over Dunsink Observatory on 10/10/2020 at 23:05 UTC (Dunsink RMS All-Sky Camera).
Bright fireball seen over Dunsink Observatory on 10/10/2020 at 23:05 UTC.

Meteors, also called shooting stars, are beautiful and short-lived streaks of light in the sky that last between a fraction of a second for the faint ones up to a few seconds for the bright ones.  They are tiny pieces of dust and rock, usually millimetre to centimetre sized, burning up as they enter the upper atmosphere at speeds of about 10 kilometres per second. Many are debris from comets and asteroids. A few are big enough to hit the ground and, very occasionally, they cause damage! Find out more about meteor observing in Ireland below.

Citizen Science and the NEMETODE Network

Members of the NEMETODE team with the Dunsink cameras in the background
Members of the NEMETODE team with Jonathan Mackey in late 2016, with the Dunsink meteor cameras.

The NEMETODE Network initiative is led by amateur astronomers as a citizen-science project, coordinating meteor-observing activities to detect and analyse meteors over the UK and Ireland. The network of cameras automatically search the sky for meteors and record the properties of any that they find. Analysing data from multiple cameras allows us to triangulate a meteor’s position, speed, trajectory, and even its orbit in the Solar System.

We joined NEMETODE with two cameras in late 2016 and a radio antenna in early 2017, funded through the SFI Discover Programme. Our colleague Michael O’Connell described our work in a BAA article from 2017. Getting started was a team effort, and we really appreciate everyone travelling from all over Ireland and even across the channel to help with the installation.

NEMETODE meeting hosted at Dunsink in September 2018
Participants at the NEMETODE meeting hosted at Dunsink in September 2018.

Since 2017 we have hosted regular meetings of the Irish and UK NEMETODE communities. Our cameras are pointed so that we have joint coverage with a number of other NEMETODE members in Ireland, and we are working to grow the network and help to fill in some of the geographical coverage gaps. Following the success of the NEMETODE cameras, we installed two higher-resolution digital cameras in October 2019, one with a fish-eye all-sky lens and the other pointed West but with wider sky coverage than the previous cameras.

A bright Perseid fireball seen to the West of Dunsink on 08/08/2020 at 23:25 UTC.
A bright Perseid fireball seen to the West of Dunsink on 08/08/2020 at 23:25 UTC.

In late 2019 we received a grant from the Royal Society Public Engagement Fund to install the all-sky meteor cameras at five more locations in Ireland, in partnership with Met Éireann, I-LOFAR, Armagh Observatory & Planetarium, CIT Blackrock Castle Observatory, and Ballycroy National Park. Delayed by everything that happened in 2020, we are assembling and testing the systems at Dunsink.

The Dunsink meteor cameras and radio antenna

The Dunsink NEMETODE (Watec) cameras and radio antenna in early 2017.
The Dunsink NEMETODE cameras and radio antenna in early 2017.

The 2016 cameras are Watec analog video cameras with approx 720×576 pixel resolution and 25 frames per second (fps). These are connected to a PC running SonotaCo UFOcapture software, which saves a frame buffer for up to 10 seconds and records video data to disk when motion is detected above the trigger thresholds. The meteor detections are checked manually to distinguish meteors from wildlife, airplanes, satellites and even fast clouds. This time-consuming process means the Watec camera images do not get processed quickly. Our cameras look south and south west, covering about 60×30 degrees of the sky.

2019 cameras: all-sky and pointed CMOS cameras controlled by raspberry pi 3b+, pre-installation
All-sky and pointed CMOS cameras with raspberry pi 3b+, pre-installation.

The radio antenna covers a much larger fraction of the sky, but we don’t have any information on the direction from which the meteor is detected. The antenna is connected to a PC and events are recorded in a data table and a spectrogram. The NEMETODE group are working on correlating visual meteors with radio detections, to learn more about how to interpret the radio detections.

The 2019 and 2020 meteor camera systems are comprised of an Ultra-low-light IMX291 camera controlled by a Raspberry Pi 3b+ unit. These systems have been developed and provided by the Croatian Meteor Network and Global Meteor Network and all software is open source. The camera operates at 25 fps for high-definition video. The all-sky cameras are fitted with an ultra-low-light fisheye lens with 180-degree field of view (FOV), and the West-pointing camera has a 100-degree FOV. The camera is powered and connected by a single connector using power-over-ethernet.

Education and research with meteors

Transition Year Week

TY students hard at work during the 2017 Dunsink Observatory Transition Year Science Week
TY students hard at work during the 2017 Dunsink Observatory Transition Year Science Week

An annual Transition Year (TY) Week was set up in February 2017 at Dunsink Observatory to expose students to day-to-day scientific research through the use of meteor data. Meteors introduce students to concepts like shockwaves, fluid dynamics, radiative processes, the structure of the atmosphere, the Solar System and orbital dynamics. Data from the meteor cameras is ideal for TY students because it does not require high-level processing, the concept of meteors is quite simple to grasp, and the mathematics used for triangulation and orbit calculation are accessible to students who have completed the Junior Certificate.

Group photo from the February 2018 TY Science Week
Group photo from the February 2018 TY Science Week, with Maria Moutzouri, Samuel McKeague, and Sam Green.

It is very rewarding to see the students applying the Sine Rule and other concepts from Trigonometry to real data (usually for the first time), and realising that they can use Maths to pinpoint the location in Ireland over which a meteor entered the atmosphere. Students from North and South Dublin and Kildare have participated in our TY Weeks. We are strongly supported by volunteers during these weeks, including Michael O’Connell, Mike Foylan, David Malone, and DIAS staff and scholars.

Machine Learning

In 2018 Mark Molloy from IT Sligo based his 4th Year Bachelor Thesis in Computer Science on developing a machine-learning algorithm to classify images from the Dunsink meteor cameras according to whether they contained a meteor or not. Former Dunsink TY student and current TCD bachelor student Sarah Joyce has also been investigating using machine learning for detecting meteors. Many of our images contain clouds, airplanes, birds, bats, satellites, cosmic rays, UFOs, etc., and sorting them manually is time-consuming. The machine-learning algorithm is excellent at excluding images that do not contain a meteor, and should make our work a lot easier!

Acknowledgements

We are grateful to our funders and volunteers for supporting Citizen Science and Education at Dunsink Observatory:

Logos of the Royal Society and Science Foundation Ireland.