Posts by Deirdre Kelleghan

Astronomical Irish Women
avatar

‘Astronomy is essentially a popular science. The general public has an indefeasible right of access to its lofty halls, which it is all the more important to keep cleared of unnecessary technical impediments’           Agnes Mary Clerke When I was president of the Irish Astronomical Society one of the most interesting guest speakers we had was Dr. Marie Bruck. She was noted for her interest in an Irish astronomer called Agnes Mary Clerke.  Back in 2007 our meeting room in Ely Place Dublin was full to  bursting point.  She delivered an eloquent talk on the centenary of the death of  this unusual lady astronomer. Her erudite presentation finished up to warm applause from all attending. Marie did her doctorate at Edinburgh University and then went on to live and work at  Dunsink Observatory in Dublin in 1950. She met and later married the director of Dunsink, Dr. Hermann Bruck.  After Dublin Marie and her husband moved to … Continue reading

What time is it? – Musings on time from zero to Webb
avatar

The concept of time on this Earth is a fictitious delusional notion to facilitate human beings to operate collectively and individually. We humans live on this Earth as it is moving through space and time at 18.5 miles per second. The imaginary line through Greenwich in London gives us a vertical starting point for longitude at zero. East away from zero adds positives in time and west away from zero produces negatives from time zero. A straight line south of Ireland reveals that vast areas of Africa and Antarctica share the same time zone as we do. The ancient Egyptians were the first to understand and put to use the concept of a year. The Egyptians kept accurate astronomical records on papyrus scrolls circa 4,500 BC. Through careful astronomical observations they realised that Sirius one of the brightest stars in the sky was visible rising next to the sun every 365 days. Exactly the days the earth takes to orbit … Continue reading

A Slice of Solar Drawing in h-alpha
avatar

On my 50th birthday my better half gave me a present of a PST 40 (Personal Solar Telescope) with a 40 mm objective. This gift was literally a piece of visual heaven. Since I acquired this fabulous instrument my work with it has always been drawing. Drawing the sun or even drawing features on the sun is without a doubt the biggest challenge in astronomical drawing. Here is the thing, the telescope objective is just 40 mm, the sun as I see it is only about 30 mm of that 40mm to the eye. Using an 8 mm eyepiece gives about a 50X magnification and therefore the best view of the features and action on the disc and on the limb. There is no point whatsoever in drawing something at a diameter of 30 mm unless you provide your viewers with magnifying glasses or the object is a daisy. Therefore I work mostly at dinner plate size, sometimes at side … Continue reading

Rhapsody in Blue – Saturn / Moon Occultation
avatar

On the evening of May 22nd 2007 the beautiful blue sky was host to a first quarter moon. The evening was to bring me one of the most visually rich observations in my drawing odyssey . When I set up my dob I really wasn’t expecting to  catch a glimpse of Saturn in a daylight sky. The software gave me an idea of where the planet was, I scanned the area in the hope of finding it. My task was to see Saturn before it went behind the unlit quarter of the moon. In my first look there it was, the white ringed planet, one billion miles away in space. Saturn was there in my eye, embedded softly in the azure sky moving swiftly toward  the invisible limb of the moon.  Nothing could have prepared me for that  revelation, it was a totally different experience to seeing Saturn in a dark night sky. My drawing paper was hastily endowed in blue … Continue reading

Sketching Eddington Crater with the Grubb refractor at Dunsink Observatory Dublin – a very nice memory
avatar

Last night I was looking up at the moon, it brought back to me a wonderful April evening in 2007 when the phase was exactly the same. That evening was to offer me a great experience in lunar sketching. When I was about fourteen years old I had my first looked through the South Refractor at Dunsink Observatory in Dublin. For months I had pestered my dad to bring me out there, a bit of a long drive in those days, before motorways existed. Jupiter was on view that evening, it was crystal clear. The planet must have been quite high as I could look through the Grubb standing on the floor of the dome. At that time I had my own little white 50 mm Tasco telescope on a short plastic tripod. There was not much to see in it, however the moon always got a look. Since that first planet view at Dunsink I wanted to revisit the … Continue reading

Cosmic Lobster Pot
avatar

I have always visualised Cassini’s journey through the Saturnian system as a kind of orchestrated cosmic dance. Cassini moves silently at great speed in its petal shape overlapping orbits. This precisely executed dance brings Cassini frequently through the icy ring plane north to south and then back again on the opposite side of the planet, south to north. This robot ship continues on its unparalleled odyssey of exploration. On board, Cassini is the custodian of twelve science instruments all primed to seek, gather, and process the offerings of this unique planetary system. Collectively they are performing one of the most important scientific probing of Saturn and its many moons in the history of space exploration. One of these science instruments is the Cosmic Dust Analyser. The CDA looks a bit like a golden lobster pot,that is not a bad analogy. This apparatus is trawling the interplanetary ocean for particles of cosmic dust, tiny particles that are the messengers of the … Continue reading

Naked Eye Orion sketched from Ireland
avatar

Recently I have spent some time in the west of Ireland . It’s been stormy , with icy rain and sideways on hailstones battering the landscape. The winds have been epic in this wild place where the ancient potato drills shout evidence of our ancestors ribs bursting the Earth , still hungry after all these years. Most evenings I have stepped outside to look up at the night sky while listening to the Atlantic roar its salty roar at stars too far away to listen. Occasionally the clarity of the sky has been impressive but short-lived. However on the evening of March 23rd on opening the door I was met with what I can only describe as a crisis sky. Every familiar constellation was buried in the galaxy. It is sometimes said that there are more stars in the night sky than grains of sand on all the worlds beaches, that sky was the epiphany of that statement. I sat … Continue reading

Eratosthenes Drawing Drama plus an Experiment opportunity for schools all over the planet
avatar

On that cold evening back in 2007 Eratosthenes looked powerful in its position emerging into the suns warm rays. Rupes Recta was also inviting and Plato almost called me again. Even drenched in sunlight Plato’s steel grey floor carried those unmistakable flame shaped shadows. Eratosthenes is a truly dramatic crater, a sweeping mountain chain whips away from it in a visual series, of broken, deep shadows. Montes Appeninus is cut and chopped first by Mons Wolf, and then by Mons Ampere. Next in line, Christian Huygens name is lent to Mons Huygens named in honour of the discoverer of Saturn’s largest moon Titan . This high mountain (164,000ft) is a billion miles away from those primal methane or ethane seas discovered by the Cassini Huygens mission on one of its routine flybys. Mons Bradley and Mons Hadley cradle the Apollo 15 lunar landing area from 1971. A mission that put wheels on the moon for the first time. This wonderfully … Continue reading

Grand Finale – Painting inspired by the Cassini Mission to Saturn
avatar

Also in Exploring the Solar System Exploring the Solar System: The Mass of the Sun Marvellous Mars Drawing Workshop at Dunsink Observatory Dublin Astronomical Sketching – Education in action Stars Wonderful Stars at Wexford Town Library Ireland Get ready the Perseids are coming Space the final Frontier – World Space Week 2016 On the richness of the lunar surface Dark Sky Magic at Ballycroy National Park Mayo Ireland Grand Finale – Painting inspired by the Cassini Mission to Saturn Cosmic Lobster Pot A Slice of Solar Drawing in h-alpha View the entire series … Continue reading

Bringing Mars to Earth – Educational Outreach
avatar

  Mars is an extraordinary planet , its textures and exquisite beauty have been brought to Earth by the images of HiRise on Mars Reconnaissance Orbiter . Curiosity gives us a ground eye view as it drove through Gale crater and on to Mount Sharp. From Earth by eye Mars is but a tiny pink dot , in small telescopes it becomes a slightly larger pink dot . It is not easy to see detail on Mars for most people. My best views were in the South refractor at Dunsink Observatory and through a friend’s 16 inch Schmidt Cassegrain.The polar caps stood out in the 16 inch while the 11.75 inch objective at Dunsink showed a hint of dark areas on the predominantly rusty pink planet body. Of course Martian dust storms and the quality of our sky has a lot to do with seeing any detail at all. Pointing out Mars in the sky for public groups and children’s … Continue reading

Lunar Drawing – Fracastorius, to Madler along the terminator
avatar

May 21st 2007 21:00UT – 22:45 UT Lunation 5.16 Days 200mm Reflector / Williams Optics Binoviewer 20mm eyepieces 2X Barlow/120 X Image not rotated 300gm Paper/Soft Pastels/Conte Crayons/Blending stick / etching tool   Many astronomers are less than fond of the moon because its reflected light takes away from their deep sky observations and imaging. Both the moonless and the moon full renditions of the sky are relished by me for different reasons. The deep dark sky for comets and messier objects, our moon for its outstanding contrast and intricate detail. My attention is captured by the interaction of sunlight with the rugged landscape. It is often difficult to choose what feature of the moon to draw when your field of view sometimes offers several exquisite potentials. The theatre of the moon is almost impossible to ignore.   Back in May 2007 I had a loan of a pair of binoviewers this sketch was the result of trying them for … Continue reading

Dark Sky Magic at Ballycroy National Park Mayo Ireland
avatar

“The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars.” – Carl Sagan There is something deeply magical about a truly dark night sky. Objects that you would strain to see or not see at all in suburbia populate every eye movement. Peripheral vision fine tunes to a state of high alert with ease. Observing rewards even before dark adaption. My visit to Ballycroy National Park in Co Mayo reminded me of so many holidays in the west of Ireland long ago when our children were young. After a day of extreme foggy conditions across the whole country I was not expecting to see any stars at all. Shortly after my talk we went outside to check up on things. Even with some small lights on in the visitors centre the sky was mind-blowing. Ballycroy National Park I had been introduced to Georgia MacMillan from the Mayo Dark Skies team by … Continue reading