Author: Peter Household

A Cork Astronomy Club public lecture held in UCC’s Civil Engineering Building

Telling the time is one of the earliest applications of astronomy, and the sundial, the earliest device to tell time of day and divide daylight into hours. James Quain, a member of Cork Astronomy Club with a lifelong interest in sundials, told how these installations work and the astronomy they are based on.

James illustrated how time is depicted, and discussed the development of sundials from the earliest known examples. 

Above: James with his Armillary Dial.

A sundial we learnt, consists of two parts: a gnomon to cast a shadow, and a dial plate.  We found out things we didn’t know we didn’t know … the extraordinary variety of sundials … James brought his own replica of a portable wooden dial as used by shepherds in the Pyrenees, and a model of the earliest known sundial consisting of two stones ─ another portable device used by the Pharaohs in 1500 BC. 

For most sundials (but not the shepherd’s dial) you need to know north.  But a solar compass from 1835 works the other way round.  It uses two very different sundials (image below), you turn it till they both agree, and hey presto, it’s facing South. The world’s largest sundial is at Jaipur in India, and the smallest consist of two metal rings that those who were rich enough in the 18th century kept in their pocket.

Finally James took grave issue with Hilaire Belloc who wrote “I am a Sundial and I make a botch, of what is done much better by a watch”

Workshop, April 15th

For Club members only, James will give a workshop with work in small groups to make a paper sundial, cut out components and assemble, set up & orientation.

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A Cork Astronomy Club public lecture

Cian O Regan talked about human factors in space flight, problems that arise and what is being done to learn how best to cope with them. Cian is a PhD student at MTU, and his thesis will investigate these questions.

Cian wears a pilot’s cap in an aircraft cockpit, at left of lefthand photo.  The recorded behaviour of pilots in emergency situations provides useful data for his research.  Right: a hypothetical Mars astronaut controlling a drone.

Sending astronauts to the Moon and Mars will pose huge challenges for the astronauts both psychological and physical, challenges which far surpass what is encountered on the International Space Station.  How will astronauts respond and will their ability to perform their duties and to respond to emergencies be impaired?  What can be done to mitigate the ill effects?

The 5 hazards of human spaceflight are radiation, altered gravity fields, hostile and closed environments, distance from Earth, and isolation and confinement.   Human factors is a field of study to reduce error and increase productivity focussing on the interaction between the human and the machine.  

Avoid the Norman door!

We heard about a Norman door, all too common in public buildings – where the design tells you to do the opposite of what you’re supposed to do, and there has to be a sign to correct it. Normanism is to be avoided at all cost in designing spacecraft.  

There’s an optimum level of arousal to maximise human performance.  Boredom at the low end (think of a 6-month journey to Mars) and strong anxiety at the high end both impair human performance.  So is it worth sending humans at all, why not just send robots?  Because humans are so much more productive than robots ─ for now, anyway.

Human factors is the field of study to reduce error and increase productivity focussing on the interaction between the human and the machine. For space agencies these are urgent questions and Cian described what has been done so far to address them, and his own research.

The lecture was live streamed over Zoom.

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Not all telescopes capture visible light. Dr Josh Reynolds, a lecturer in the Department of Physical Sciences in MTU, told us about VERITAS – a ground-based very high energy (VHE) gamma-ray instrument.  It operates at the basecamp of the Fred Lawrence Whipple Observatory 1.3 km above sea level in southern Arizona USA, and consists of four 12 m Imaging Atmospheric Cherenkov Telescopes (IACT) which use Cherenkov shower imaging to detect gamma-ray photons with energies above 85 GeV. 

Josh covered the history and science of VERITAS along with a personal account of tours of duty to the observatory as a VERITAS collaborator, and didn’t neglect to tell us about the poisonous toads that inhabit the site. 

The lecture wase live streamed over Zoom.

About Dr Josh Reynolds

Dr Reynolds has been a member of the VERITAS collaboration since its inception in 2003 (as well as being a member of it progenitor, the Whipple Observatory collaboration) and a co-author of the publication that announced the discovery the Atmospheric Cherenkov Imaging Technique in 1989. He also lectures in the Department of Physical Sciences in MTU.

More about VERITAS

VERITAS (Very Energetic Radiation Imaging Telescope Array System) is an international astrophysics collaboration between the USA, Canada, Ireland and Germany, involving 9 founding institutions and 15 collaborating institutions (MTU is a collaborating institution). It operates a ground-based gamma-ray instrument at the Smithsonian Institution’s Fred Lawrence Whipple Observatory (FLWO) in southern Arizona, USA.  This is an array of four 12m optical reflectors that uses the Imaging Atmospheric Cherenkov technique to perform gamma-ray astronomy in the GeV-TeV energy range. Very High-Energy gamma rays are associated with exotic cosmic objects such as supernovae, pulsars, quasars and black holes. Expensive, space-based observatories are normally required to detect gamma rays as they are absorbed in the atmosphere, but VERITAS is able to use the Atmospheric Cherenkov Imaging technique to observe them from the ground.  VERITAS has a prodigious research output, with 162 publications in peer-reviewed journals (44 over the last 5 years) including publications in Science, Nature and Nature Astronomy. 

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The James Webb Space Telescope (JWST) is on the lips of every astronomer.  Dr Niall Smith of MTU and the brains behind Cork’s Blackrock Castle Observatory told us why.  Launched on Christmas Day 2021 JWST is sending back images of the universe in previously unimaginable detail.  Crucially this telescope observes in the infrared, which is necessary when observing the early universe. Early means far away and moving fast from us, thus extremely red-shifted, hence undetectible in the visible spectrum where the Hubble Space Telescope operates. JWST will supply new information about the early universe, indeed already has done, which will change our knowledge of how it all began and where it’s headed.  

One of our favourite speakers,  we were delighted to welcome Niall to launch our new season of monthly lectures,  which after a long Covid-induced absence, will once again be held in our old home of University College Cork’s Civil Engineering building.   

The lecture was live streamed over Zoom.

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