Saturday, 7 May 2016

Mercury Transit events and lecture, Talks, TCrB, Mayo Dark Sky, Solarfest, BBQ

Hi all,
1. Transit of Mercury, 9 May: The IAA will be holding a public observing session for this rare event, in conjunction with the ARC of QUB, in front of Queen's University, University Road, Belfast. The transit will be visible from 12h 12m to 19h 40m, BST. Bring your telescope if you have one - but see below.
The viewing session will finish with a special free lecture in QUB at 8 p.m., as part of the Michael West series - see below.
We will also be holding a similar event at Portballintrae, Co Antrim, at the Agherton Parish Centre, from 12.00 until the end of the event.
NB! You must NOT attempt to view this event without proper safe equipment. As a general guide, the rule is to treat it as if it was a partial solar eclipse. Note that you should NOT try to observe it using eclipse glasses along with binoculars or a telescope; eclipse glasses are safe only for naked-eye viewing. If in doubt, don't try it!

This will be the first Mercury Transit visible from Ireland since May 2003, and the next one will occur on 11 Nov 2019, but the Sun will set before the end of that transit.

Of the 12 transits up to 2100, 2 are completely invisible from Ireland, 6 are partly visible, and only 3 more are entirely visible; the next one of those will be on 7 May 2049, so this is a chance that you really should not miss!

And this one will have the longest duration of any visible in Ireland this Century!


Mercury appears much smaller than Venus during a transit; the apparent diameter this time will be only 12.06", and so optical aid will be required. This can be either a proper solar filter on a telescope as used for normal solar observing, or you can project the image through a telescope onto a piece of white paper or card. Mercury will appear as such a small black dot that it will be barely visible with binoculars (also fitted with proper solar filters of course!) unless they are of fairly high power, say 12x or more.

Mercury will first appear as a tiny little black notch (if you use sufficient magnification - say 100x) at the E side of the Sun, and gradually move across the Sun's disc, passing South of the Centre, and exiting the disc on the SW limb. Remember that these directions are relative to the Sun's N Pole, not to its orientation in the sky, which will change during the transit.

Looking for First Contact is the hard part - once the transit is under way it will be fairly easy to follow. Also remember that in an astronomical telescope, directions can be reversed both N-S and E-W depending on the optical design, and whether a diagonal is used at the eyepiece!

The best way is to let the image drift through the field of view (switch off your drive for about 30" or so, and see how it drifts) – the side of the Sun's disc which is leading the direction of motion is the preceding side, and the opposite is the following side.

East will be fairly close to the following side at the start of the event. For more accurate location, at the start of the transit, Mercury will enter onto the Sun's disc just very slightly S of the E limb of the disc as the Sun appears in the sky at that time – say about '8.45' on a clock face. By the time the transit is ending, it will appear just very slightly W of the apparent S point on the Sun's disc at that time – about 5.45 on a clock face.


Do NOT attempt to image with a camera unless the optical system is fitted with a proper filter as above. Above all, do not try to image through a telescope unless it has a proper filter! You will need quite a high effective magnification to get an image showing Mercury clearly.

You can however easily take a photo of the Sun's image projected through a telescope onto a piece of white card: you may need to get in close to see Mercury clearly.


The Sun will be just N of West at the end of the transit, and down to an altitude of only 11 degrees, so make sure you have a good view in that direction if you want to see the whole event.


More info & details of how to observe & make a filter are on a post by Seanie Morris at
Online viewing: The European Space Agency (ESA) will web stream live images throughout the transit at: Live images will also be broadcast via a live Google Hangout, which will be on air throughout the transit. For details, see:
Events: Details of public observing events relating to the transit of Mercury can be found at These can also be viewed on a map:
Social Media: For live updates during the transit, follow the hashtag: #mercurytransit Share your selfies from Transit of Mercury observing events with the hashtag: #MercuryTransitSelfie.
Videos: Animation introducing the Transit of Mercury by Europlanet 2020 RI:
The Open University's "Discover Mercury" series of videos include how to view the transit of Mercury safely, as well as features on the science and geology of Mercury and the MESSENGER and BepiColombo missions.
Transit of Mercury Schools Challenge: The European Space Agency is challenging European school students to observe the transit and to recreate the measurements made by astronomers around 300 years ago in order to calculate the distance between the Earth and the Sun.
LOCAL: For more local details see the IAA website and http://airmail.calendar/2016-04-25%2012:00:00%20BST
2: FREE PUBLIC LECTURE, QUB, 9 May 20.00: "Einstein's Gravity: from the transit of Mercury to the detection of gravitational waves": Larmor Lecture Theatre, Physics Building, QUB: In the next Michael West Lecture, Professor Patrick Brady of the Center for Gravitation, Cosmology & Astrophysics, University of Wisconsin will describe the 100-year path of Einstein's theory of gravity, from explaining the orbit of Mercury to this year's first-ever detection of gravitational waves, and what we might see through the opening of this new window on the Universe. Admission to the Larmor Lecture Theatre is free, but registration is required. Registration for the lecture is now live so book now to reserve a place.

3. Mercury on The Sky at Night:
BBC FOUR, Sunday May 8, at 10 p.m.: "Mercury: The Problem Child of the Solar System". Repeat on Thursday May 12 at 7:30pm.
4. Commemorating the Discovery of R. Nova T Corona Borealis:
The Galway Astronomy Club will celebrate the 150th anniversary of the discovery of the flaring of T Coronae Borealis by Tuam amateur astronomer John Birmingham: on the 9th in Galway, and to the day on the 12th in Milltown itself where the discoverer's telescope is on permanent display in the Heritage Centre (opened by President MacAleese in 2005). See
5. Public lecture, May 10, entitled "Science from High Altitude Balloons" will be held in UCD as part of the ANSRI 2016 workshop. The talk will be given by Prof. Mark McConnell of the University of New Hampshire. Venue is Room 129 Science Centre North, UCD, at 6pm. More details at
6. PUBLIC LECTURE, May 18: "Beauty and Truth in Mathematics":
The statutory public lecture of the School of Theoretical Physics (DIAS) will be given this year by Prof Arthur M Jaffe of Harvard University. Venue is the Schrödinger Lecture Theatre, Fitzgerald Building (School of Physics), TCD at 7pm on May 18th. Book via
7. Congrats to Mayo Dark Sky Park
"First International Dark Sky Park In Ireland Receives Accreditation:
The International Dark-Sky Association has granted Gold-Tier International Dark Sky Park status to Ballycroy National Park & Wild Nephin Wilderness – to be jointly recognised as Mayo International Dark Sky Park.
County Mayo is widely celebrated for its rugged and unspoiled landscape on the edge of Europe's wild Atlantic coastline. A Gold tier classification is an honour reserved for the most exceptional of dark skies and stunning nightscapes. This recognition completes the "360 degree experience" that this stunning region has to offer.
The award is the first International Dark Sky Park in Ireland and is a wonderful recognition for the region's pristine skies, enhancing its existing protected landscapes and wilderness regions. This is the second IDA designation in Ireland. The first is Kerry International Dark Sky Reserve in County Kerry.
"Today's announcement is a wonderful outcome for both dark skies and economic development in rural Ireland," IDA Executive Director J. Scott Feierabend said. "County Mayo joins Kerry as a haven of natural darkness for both wildlife and human visitors alike."
Ballycroy National Park and the adjoining Wild Nephin Wilderness expands over 110 square kilometers of mountainous Atlantic blanket bog and forest. Viewing sites for visiting astronomers have been designated and graded by ease of access and facilities available. Signature viewing sites include the Claggan Mountain Boardwalk, Letterkeen Bothy and Ballycroy National Park Visitor Centre, which have excellent interpretive and parking facilities.
"Ballycroy National Park and Wild Nephin are honoured to have received Gold tier International Dark Sky Park Status" National Parks and Wildlife Service Regional Manager, William Cormacan said. "We are fully committed to preserving our pristine dark skies and are excited by the many opportunities that this accreditation will present for local tourism, businesses and the park."
The Mayo Dark-Sky designation follows a lengthy period of night sky surveying and quality monitoring by students of Galway-Mayo Institute of Technology. Assisted by Professor Brian Espey of Trinity College Dublin's Astrophysics Department, the research resulted in collaboration among communities in Newport, Ballycroy & Mulrannny together with Ballycroy National Park, Coillte Forestry, Mayo County Council, Mayo South West Development and Galway Astronomy Club. The group formed the "Friends of Mayo Dark-Skies" steering committee and submitted the application for dark sky status earlier this year.
"We are thrilled with the award. The project has been embraced by so many parties and is the first collaboration of its kind between a National Park, Coillte and surrounding communities," Project Manager Georgia MacMillan explained. "Our nightscapes are inspirational and worth protecting for future generations. It's hoped that achieving this award will not only showcase the area for the growing market of astro-tourism, but also raise awareness of the impact of light pollution on our environment and biodiversity."
Mayo County Council has committed to dark sky friendly lighting in the area and is working with the Friends of Mayo Dark-Skies group to further reduce light pollution where possible.
The Mayo International Dark Sky Park already has some exciting events planned for the coming months, including The Mayo Dark-Sky Festival to be held 28-30 October. A formal launch event will be announced shortly and a full schedule of dark sky events and educational programmes will be available from Ballycroy National Park."
(I was there on holiday last year, and confirm that it's an unspoiled wilderness with very dark skies. Congrats to all concerned. T.M.)
8. Pint of Science talks have definitely been organised for Galway (May 23rd and 24th) and Limerick (May 25th), and details for Dublin are expected shortly. More details can be found at
9. Solarfest, Dunsink Observatory, Dublin: Sat 11 June. More details when available.
10. IAA Midsummer BBQ: 18 June. Venue and details TBA. (Probably at Armagh Planetarium, to include a starshow there).
11. Festival of Curiosity 2016 (July 21st to 24th) See
12. Space camps at Blackrock Castle Observatory. See
13. IAA Telescopes for loan: The IAA has telescopes available to borrow, for any paid up member Enquiries to David Stewart or Andy McCrea

14. Interesting Weblinks
SETI * The 'exoplanet 6 times the size of the Earth' is NOT orbiting either of the two bright stars in the background, and the illumination on the planet is wrong.
SPACE: Nice time exposure. Polaris is centre left with the rest of UMi above right of it. Vega is the bright star below the top of the arc, with Deneb below left of Vega, and Altair bottom right, the latter three forming the Summer Triangle.
The illustration has a serious error - shadows on the Moon are normally completely black, as there's no atmosphere to give light from directions other than the Sun. Earthshine would give some light at 'Full Earth' phase, but you only get that on the dark side of the Moon. A slightly gibbous Earth is shown here, and would give some light, but not as much as is shown. I'm still skeptical about this. In any case, they repeat the fallacy of 'getting humans to the moon in 4 hours, and to Mars in 10 weeks'. That would be true if you didn't mind smashing into your destination at many tens of thousands of MPH! In other words, they ignore the need to decelerate and land safely!
15. TWITTER Follow the IAA on Twitter: @IaaAstro.
16. JOINING the IRISH ASTRONOMICAL ASSOCIATION is easy: This link downloads a Word document to join the IAA.
If you are a UK taxpayer, please tick the 'gift-aid' box, as that enables us to reclaim the standard rate of tax on your subscription, at no cost to you. You can also make a donation via Paypal if you wish: just click on the 'Donate' button. See also
Clear skies,
Terry Moseley

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