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!
OBSERVING:
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.
IMAGING:
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.
TRANSIT END:
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:
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.
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."
14. Interesting Weblinks
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