1. IAA PUBLIC MEETINGS CANCELLED until further notice.
Because of the Covid-19 virus outbreak, the next lecture meeting has been cancelled. The AGM which was scheduled for April 15 has been postponed: a new date will be notified as soon as the situation becomes clearer: it may not be possible to hold it until September. Observing sessions at Delamont have also been cancelled until further notice.
2. Dark Sky observing event, Cavan Burren Park centre, 20 March, Unfortunately this event has now also been cancelled because of Covid-19. It's hoped to re-arrange it some time in the future.
3. EQUINOX Mar 20 at 03h 49. This is the earliest N. Spring equinox for 124 years. The Sun will cross the celestial equator going Northwards in its apparent annual journey round the sky on Mar 20 at 03h 49 This will mark the start of N. Hemisphere spring, and S Hemisphere autumn. "Equinox" means that 'day will be equal to night', but of course that's only approximately true. That's because 'sunrise' is defined as the moment when the upper limb of the Sun first appears above the E horizon, and 'sunset' as when its upper limb disappears below the W horizon, rather than the centre of the Sun in each case.
Further, atmospheric refraction actually makes the Sun appear elevated by about half a degree from its true position, so that it appears to have fully risen while it is actually still totally below the horizon. Conversely, the refraction effect makes it still appears to be above the W horizon when it has actually set. These effects combine to make apparent day about 20 minutes longer than the time when the Sun appears to be below our horizon.
Finally, at least one online website used to state that at the equinoxes, no matter where you are on the Earth, 'the Sun rises exactly due East and sets exactly due West'. This of course is not true, especially at our latitudes. The first and most obvious point is that the Sun is moving either N or S at the equinoxes, so if it rises due E, by definition it cannot set due W which will be about 12h later! However, this effect would be very small, amounting to about 11 arcminutes.
However, at our latitudes the Sun rises and sets at a considerable angle to the horizon, and the effect of refraction makes the Sun appear about 0.6º higher than it actually is, which makes sunrise appear earlier, and sunset later, than if we had no atmosphere. And because of the angle of the ecliptic to the horizon, for us that makes the Sun rise North of due East, and set North of due West, at the equinoxes. Further, sunrise and sunset apply to the upper edge, or limb, of the Sun, which exaggerates the effect. Combined, these effects shift the spring rising point by about 1.25 degrees Northwards. That's about 2.5 solar diameters, so it is significant. Not that much, but enough to make it wrong to use the term "exactly".
I'm glad to say that after several years of me haranguing them, one website has indeed accepted my points, and changed their definition!
4. COSMOS STAR PARTY, Athlone, (3-5 April) POSTPONED. Unfortunately this has had to be postponed because of Covid-19 risks. It may be possible to hold it sometime later I'll keep you informed.
4. COMET ATLAS IS BRIGHTENING FASTER THAN EXPECTED: Get ready for another nice comet. Comet ATLAS (C2019 Y4) is plunging toward the sun and, if it doesn't break up first, it could become one of the brightest comets in years. Amateurs are already getting fantastic images as the comet brightens even faster than expected. You can get its position from heavens-above.com
5. The Impact of Satellite Constellations on Astronomy: IAU press release
https://www.iau.org/news/pressreleases/detail/iau2001/
6. Astronomy Stamps. A new set of stamps has been issued in the UK, with the theme Visions Of The Universe, marking the 200th anniversary of the RAS. You can buy various sets, or buy them singly.
7. Venus. You can't miss brilliant Venus in the SW evening twilight. Watch as it moves ever higher out of the bright twilight over the next few weeks as it approaches its pass through the Pleiades on 3 April.
8. ISS will start a new series of evening passes on 20 March. Full details for your location, and lots of other astronomy information, on the excellent free site www.heavens-above.com
9. BETELGEUSE continues to brighten. Betelgeuse reached a minimum magnitude of about mag 1.6, and is now slowly brightening again: it's about 1.2 at the moment. There are two theories for the unusually deep minimum; firstly that it was caused by the minima of at least two separate cycles coinciding round about Feb 22, or that it was due to the shedding of dust from its outer layers, which has now thinned out and become more transparent.
Watch it for as long as you can – into early April, at a stretch - to see how much it brightens again. You can compare it with Procyon (mag 0.4), Aldebaran (mag 0.87, but slightly variable itself), Pollux (mag 1.16), Castor (mag 1.58), Bellatrix (mag 1.64). Only do it when Betelgeuse is at least 30 degrees above the horizon, and choose comparison stars at about the same altitude as it.
10. Asteroid Day, 30 June.
Asteroid Day was co-founded by astrophysicist and famed musician Dr. Brian May of QUEEN; Apollo 9 Astronaut Rusty Schweickart; Filmmaker Grig Richters; and B612 President Danica Remy, to promote awareness and provide knowledge to the general public about the importance of asteroids in our solar system history, and the role they play in our solar system today. Events are scheduled leading up to 30 June, the date of the largest asteroid impact of Earth in recorded history (Tunguska).
11. International Astronomical Youth Camp in Spain, 12 July – 1 August
The International Astronomical Youth Camp (IAYC) is a three-week long summer camp aiming to promote knowledge of astronomy and related sciences in a unique international atmosphere. The IAYC is an experience unlike any other; a place for unforgettable memories and lifelong friendships. During the camp, 65 young and enthusiastic participants from all corners of the world gather in a remote location in Spain to observe and learn about some of the most spectacular skies on this Earth. Applications for the 2020 camp are being accepted until 5 April 2020.
International Astronomical Youth Camp, 12 July-1 August 2020; Baños de Montemayor, Spain
More information and application are here: www.iayc.org
12. National Astronomy Week, 14 – 22 November.
National Astronomy Week (NAW) will be held in the UK from Saturday 14 November to Sunday 22 November, to celebrate the close approach of Mars. Amateur and professional astronomers will be holding observing events during the week. Seen through a telescope magnifying about 100 times, Mars will appear as a pale orange disc, with its markings clearly visible, at a distance of 80 million km.
Although Mars is at its closest to Earth a month earlier, by November it is well up in the sky during the early evening, allowing younger schoolchildren an opportunity to get a good view of the planet. It will not be as close again until 2033. As well as Mars, Jupiter, Saturn and the Moon will be on show during National Astronomy Week. Details of observing events will be posted on the NAW website.
13. Death of Al Worden. Sad news: Al was the CM pilot on Apollo 15. I was lucky enough to have dinner with him at the Kennedy Space Centre just over a year ago. A great and lovely man.
14. INTERESTING WEBLINKS (Disclaimer - Use of material herein from various sources does not imply approval or otherwise of the opinions, political or otherwise, of those sources). NB: If the title in the weblink does not indicate the subject matter, I give a brief simple intro before the link. I may also comment about the link afterwards.
ASTROPHYSICS
Turbulent convection in stellar interiors https://www.sciencedaily.com/releases/2020/03/200309130029.htm
Odd star pulsates on one side only https://www.sciencedaily.com/releases/2020/03/200309130013.htm
EHT produces razor-sharp images of Black Hole https://www.sciencedaily.com/releases/2020/03/200318143757.htm
EARTH & MOON
https://www.dailymail.co.uk/sciencetech/article-8104801/Energy-renewables-cheaper-coal-says-report.html Thank you, Sun.
https://www.dailymail.co.uk/sciencetech/article-8095923/Ancient-human-settlement-obliterated-COMET-exploding-Earths-atmosphere-12-800-years-ago.html Good video on Hera / Dart mission!
New theory of origin of Earth's magnetic field. https://www.sciencedaily.com/releases/2020/03/200315102257.htm
IMAGES
https://www.dailymail.co.uk/sciencetech/article-8126843/Hubble-captures-spectacular-image-bright-pink-star-forming-cloud.html The Zoom-in is incredible – be sure to watch it!
From the Moon to the Multuiverse – amazing size comparison video https://youtu.be/GoW8Tf7hTGA
SOLAR SYSTEM
SPACE
https://www.dailymail.co.uk/sciencetech/article-8101781/NASA-astronauts-head-ISS-aboard-SpaceXs-Crew-Dragon-early-MAY.html Some poor proof-reading here. "…will not position…" should read "… will not only position…". A few others too, but that's the worst.
https://www.dailymail.co.uk/sciencetech/article-8096279/Elon-Musk-fears-die-makes-Mars-SpaceXs-lack-progress.html I'm sure Mars won't mind!
Remembering Alexei Leonov: the first spacewalker, who nearly didn't get back https://www.msn.com/en-gb/news/in-depth/the-first-spacewalk-could-have-ended-in-tragedy-for-alexei-leonov-heres-what-went-wrong/ar-BB11o4mW?ocid=spartandhp
https://www.dailymail.co.uk/sciencetech/article-8104451/Mars-rover-mission-delayed-two-years.html
TELESCOPES, EQUIPMENT, TECHNIQUES
EHT produces razor-sharp images of Black Hole https://www.sciencedaily.com/releases/2020/03/200318143757.htm
New telescope design could give unprecedented detail over a wider field https://www.sciencedaily.com/releases/2020/03/200318143748.htm
15. JOINING the IRISH ASTRONOMICAL ASSOCIATION. This link downloads a Word document to join the IAA. http://documents.irishastro.org.uk/iaamembership.doc
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The Irish Astronomical Association is registered with The Charity Commission for Northern Ireland NIC 105858
DISCLAIMER: Any views expressed herein are mine, and do not necessarily represent those of the IAA.
Clear skies,
Terry Moseley
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