Posts by Deirdre Kelleghan

21 Precious Perseids viewing pleasure
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My observing location for the 2017 Perseids was flanked toward the east by a large stony hill. Towards the west  the Atlantic Ocean and to both the south and north by fields of sheep. All week the forecast was less than favourable. It was a treat to have a relatively clear sky. Between local time 22:40 ( 21:40UT) and 23:35 ( 22:35UT) I observed 19 beautiful Perseids. Two white ones to start then a stunning blue mag 3 which spanned the width of Ursa Major. The vast majority were white with the occasional dim red Perseid zipping in from the direction of Perseus. Several of the white variety matched magnitudes of 2 + similar in brightness to many ISS passes. Some of them entered directly overhead, they spurted and spluttered their smoky trails just in case they were not noticed. On this occasion, I did not create a drawing, but simply enjoyed watching the show. The Milky way became increasingly … Continue reading

Get the Moon in your head – Learn from Galileo and Apollo 11
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          Learn from  Galileo – 1610 ‘At conjunction the moon occupies a position between the sun and the earth; it is then illuminated by the sun’s rays on the side which is turned away from the earth. The other hemisphere, which faces the earth, is covered with darkness; hence the moon does not illuminate the surface of the earth at all. Next departing gradually from the sun, the moon comes to be lighted partly upon the side it turns toward us, and its whitish horns, still very thin, illuminate the earth with a faint light. The sun’s illumination of the moon increasing now as the moon approaches first quarter, a reflection of that light to the earth also increases. Soon the splendour on the moon extends to a semicircle, and our nights grow brighter; at length the entire visible face of the moon is irradiated by the suns resplendent rays, and at full moon the whole … Continue reading

Kicking up some more dust – Apollo 11 Memories part 2
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The Apollo 11 Moon landing in July 1969 had a profound effect on my life. It gave me an interest in astronomy and space that has stayed with me ever since. It has inspired my paintings and my outreach education efforts later in life. In September 1969 I went back to school full of anticipation that my teacher would talk about the biggest global event of the summer. For some reason I truly thought, she would tell us more about it and make a big deal of it in class. No, not a word, not a mention, nothing at all. I was beyond disappointed at the time, that has stuck in my craw ever since. Back in 1969, you did not really engage with your teacher, ask questions or bring up issues. You sat at your desk (wooden with an ink well) with 54 other children and absorbed whatever they dished out. My last year in primary school was in … Continue reading

Kicking up some dust – Apollo 11 Memories Part 1
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July 20 1969, I was  12 years old living in a regular suburban house with regular suburban parents. In my family I the eldest of five at the time. As with most families then we had to be in bed at 8 pm on weeknights, maybe 9.30pm at weekend’s school holidays or not that was the way it was. The Moon landing held a big interest for me, I really wanted to see it. Irish TV (Telefis Eireann) were going to cover the story with a special programme. Much to my surprise, the pestering of my parents in just the right way and at just the right time produced a yes. Deirdre was allowed to stay up and see how the story unfolded. Telefis Eireann didn’t start broadcasting until 6 pm in those days, the Moon landing programme started at 9 pm and was presented by Kevin O’Kelly. We had a small black and white TV with a rabbit-ear aerial. … Continue reading

The Bay of Rainbows and a bag of carrots
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The Bay of Rainbows in the Ocean of Storms ( Sinus Iridum in Oceanus Procellarum). What an atmospheric description of a dry colourless area on our moon. Sometimes when I am speaking about the moon to children I often say that the Bay of Rainbows is one of my favourite observing areas . The title of the feature brings up visions of a safe and happy place in a vast ocean of grey rock . The Bay of Rainbows is on the edge of The Ocean of Storms, a safe heaven is conjured up despite the fact that the moon has no seas or storms. The Sinus or Bay is the remains of a large impact crater which was subsequently flooded by basaltic lava, far from a safe place during its formation. The general surface of the bay is relatively flat but has a number of Dorsa aka wrinkle ridges. The ridges form when cooling magma shrinks and following magma … Continue reading

Astronomical Irish Women
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‘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
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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
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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
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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
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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
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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
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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