Mercury Transit on May 9th 2016

jfSDAS

Hi all,

On Monday, May 9th, the planet Mercury will pass across the face of the Sun, taking 7.5 hours to do so. We'll see the entire event from Ireland. The last such transit of the innermost planet visible from here was 13 years ago while the next occasion will fall in 2019 and then not until 2032.

The transit on Monday begins at 12:12pm (summer time) and ends at 19:42 (summer time).

Of the 12 transits that occur up to 2100 AD, two are completely invisible from Ireland, six are partly visible, and only three more are entirely visible: The next one of these will be on May 7th, 2049. And next Monday's event is the longest transit visible from Ireland this century!

Mercury's disk will be only 1/158th the diameter of the Sun so some magnification is necessary to see it as a tiny dot slowly threading its way across the solar disk. However, the only safe way of doing so is to project the image or use a suitable solar filter. If in doubt then check with your local astronomy club (details at the end). Seanie Morris of Midlands Astronomy Club has a great guide on how to safely observe the transit posted to www.irishastronomy.org

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.

The Sun will be just N of West at the end of the transit, and at a much lower altitude (roughly between 11° to 13.5° up depending on where you are in Ireland), so make sure you have a good view in that direction if you want to see the whole event.

Clear skies (we hope!)

John


More information about the transit and what to expect can be found at the following links:

• http://eclipsewise.com/oh/tm2016.html
• https://astronomynow.com/2016/05/01/rare-transit-of-mercury-to-take-place-on-9-may/
• http://www.skyandtelescope.com/astronomy-news/observing-news/get-ready-for-may-9th-transit-of-mercury-041320162/
• https://www.theguardian.com/science/across-the-universe/2016/may/06/how-to-see-mercury-transit-the-sun-on-9-may

Europlanet clip about Mercury and the transit ... https://www.youtube.com/watch?v=JqFFJ6zdECw&feature=youtu.be


A number of events will be held around the country:

Public viewing at Rathbeggan Lakes hosted by Meath Astronomy Club. See https://www.facebook.com/pages/Meath-Astronomy-Club/753390101339005

The Irish Astronomical Society will have telescopes set up by the Bandstand in St Stephens Green in Dublin city centre from 11am to 4pm. See http://www.irishastrosoc.org/

The Irish Astronomical Association will be holding an event in Belfast.They will be in front of Queen's University, University Road, Belfast. See http://www.irishastro.org/

Astronomy Ireland have an event at their HQ in Blanchardstown. See www.astronomy.ie

The Solar Physics Group in TCD will be set up in the Front Square of the College from noon. They'll have telescopes along with a plasma screen broadcasting a live view of the event from the Solar Dynamics Observatory. More details at https://www.tcd.ie/Physics/news-events/events/mercury-transit/

Blackrock Castle Observatory in Cork is hosting an event to observe the transit. See http://www.bco.ie/2016/05/transit-of-mercury/

The European Space Agency (ESA) will web stream live images throughout the transit at: http://www.cosmos.esa.int/web/cesar/streaming

ESA is also 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. http://www.esa.int/Education/Teachers_Corner/Transit_of_Mercury_schools_challenge

FREE PUBLIC LECTURE, Queen's University Belfast on May 9th at 8pm: "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. http://go.qub.ac.uk/arc-events


Transits in a historical context:

I have posted a slideshow (as a pdf) and the slide notes to the links below.

https://www.dropbox.com/s/lci1v3cbo44ig8l/ToM.pdf?dl=1 (1.2Mb)
https://www.dropbox.com/s/xnfrr3j9wsb24az/TransitNotes.pdf?dl=1 (70k)

Slideshow summary ... The first Mercury transit to be observed was in 1631 and this enabled astronomers to finally pin down Mercury’s orbit. However, the subsequent discovery of a slight discrepancy in Mercury’s motion led to one of the more celebrated wild goose chases in astronomical history.

Astronomers of the 19th century at first suggested the tug an intra-Mercurial planet – which they dubbed Vulcan -- was causing Mercury to deviate in its orbit. Observers searched for this rogue “planet” for decades but without success. Although never found, their scrutiny did lead to the serendipitous discovery of the sunspot cycle.

Ultimately, the residuals in Mercury’s orbit were neatly explained as a consequence of Einstein’s Theory of Relativity and the need for Vulcan vanished. How astronomers solved Mercury’s maverick motion is one of the more remarkable stories in astronomy.

Although looking for Vulcan proved fruitless, we can take it as a salutary lesson in how science works. Sometimes it does blunder down blind alleys but it is by doing so we learn to backtrack and ultimately figure out the correct path.


Notes: the details above also include info from the IAA mails posted by Terry Moseley, while the slideshow notes are compiled from various web pages, books, and articles on the subject of Mercury transits and the hunt for Vulcan.

mickmackey1

Brilliant post John, thanks.

uck51js9zml2yt

Great post john.
I'm heading to rathbeggan with junior. And collecting a new scope off Stephen ( hope he remembers to bring it!)

jfSDAS

Cheers everyone! Forecast is looking good for the day and with such a long event we should get some clear spells even if some cloud is around.

I'll be at Rathbeggan Lakes too! Have to be back in Dublin for 4pm though but should catch the last hour of the transit afterwards from the City.

John

ps200306

Near-live pictures of the transit will be available at:

http://mercurytransit.gsfc.nasa.gov/

... for those who prefer to watch from their bed! :eek:

Gremlin

All going well, I'll be running a live feed from Raheny Observatory starting at 11:30 (ish).

http://www.ustream.tv/channel/cq5f5TeXrta

All welcome to login.

Bongalongherb

I'm going to give this a shot on the video equipment I have if a clear sky in the east. It will be interesting indeed.

'Just Great' Early mist clearing this morning. Some warm sunshine will develop in parts of Connacht and Ulster, cloudier further south and east, but there will still be some hazy sunny spells in places. Well I hope folk on the west or Midlands get a good clear spell.

philstar

yer man on the bbc says its risky pointing a telescope at the sun for a long time as it'll damage the insides with the heat

cowboyBuilder

So I got my baader solar film ... have my binocs ready and my 400mm lens ... and it's bloody cloudy here !!!:mad::mad::mad:

muskyj

Overcast in galway so far. Sun struggling to break through. If anyone knows of better skies anywhere nearby please post.
Btw great post John. Plenty of reading last night!

Bongalongherb

Terrible conditions in north Co. Dublin, it's a no-go for the day.
Can some-one afford to purchase an aircraft for a few free hours from Baldonnel ?.
It's the only way to get above the clouds in Dublin.

rolion

I'm in Dunboyne,on the way to event....i can see Mercury but ... where is the Sun !??

rolion

What a day....

cowboyBuilder

Guardian have live coverage - good livecam from the greenwich observatory

https://www.theguardian.com/science/live/2016/may/09/transit-of-mercury-2016-follow-todays-celestial-event-live

cowboyBuilder

From 1907 ...




Smoking glass ???

Jesse Pinkman ??!!!!

SCIENCE BIATCH!!!

Veloce

Hi John

I managed to head in to Stephens Green on my lunch break today - great setup and was delighted to get a glimpse of the transit (and an aircraft flying right by leaving a pair of contrails!)

Here is a picture taken at lunchtime:

gizmo555

shedweller

Got a photo earlier but the clouds rolled in shortly after. There is a clear patch coming over louth/meath/north dublin now so all is not lost!

shedweller

ZeRoY

Here's my effort for today, stack of 6 shots taken from Louth at 2.40pm today

shedweller

Now thats quality. Top job zeroy!

jfSDAS

Great pictures everyone! Many thanks for sharing. There's some really dramatic shots there and they nicely capture how small Mercury looked silhouetted against the Sun.

I left Dromineer early yesterday morning with the Sun barely visible through the cloud and you could probably have heard the wail of despair for miles :-) The sky seemed to perk up as I neared Rathbeggan Lakes and it was great see so many scopes and other gear set up at the venue. Many thanks to Kevin for breakfast and keeping the BBQ going during the day! Got the odd clear spell there and a peek at Mercury through Michael Murphy's scope (sorry for bumping it Michael later on!) I had to leave Rathbeggan at 2:30pm though and just a couple of miles closer to Dublin it was spitting rain.

Anthony and a few others at Rathbeggan were getting updates from people on the weather elsewhere. The IAA group in Belfast were having great success and I heard from the IAS on St Stephens Green who had over an hour of clear skies at lunchtime.

Love that picture Veloce of the IAS group set-up: Mick McCreary on the left with the Dobsonian, Peter Denman seated (in the brown jacket) with the PST, Val Dunne (blue shirt) peering through the Celestron 8, and John Dolan (in baseball hat) standing on the far right. All great guys who were the driving force behind the Images of Starlight exhibition in the Botanic Gardens in February.

Headed up to Dunsink Observatory for 5pm as a group of 70 scouts were visiting later. I set up the TV 102mm to project the image and the sky around the Sun cleared just after 6pm. The scouts were thrilled see the transit and many thanks to Maria and Howard who helped out in explaining what was happening, and to Val and Mick from the IAS who brought their scopes along from the Green to allow direct viewing of the transit in white light. I didn't see the end of the transit as we had moved inside to start the talk but cloud had moved over the Sun by that stage.

Overall, while I didn't see the event in its entirety, I'm pretty happy to have had the opportunity share the transit in the company of lots of people throughout the day.

John

gizmo555

It's fascinating that the technique used by the Kepler mission to identify exoplanets is to measure the minute dip in the observed brightness of the stars they orbit as a transit occurs.

Astronomers have confirmed the discovery of 1,284 new planets by the Kepler space telescope, including nine Earth-like worlds that could potentially harbour life.

The announcement, made by scientists from the American space agency Nasa, more than doubles the tally of “verified” Kepler planets orbiting distant stars.

Of the nearly 5,000 total planet candidates found to date, more than 3,200 have now been confirmed as genuine worlds and of these 2,325 were discovered by Kepler.

The new finds belong to a catalogue of 4,302 potential planet candidates identified by Kepler, which was launched in March 2009 and orbits the Earth at a distance of 100 million miles.

Before confirming the discovery of a new “exoplanet”, astronomers have to make sure the candidate is not another object such as a companion star or brown dwarf . . .

. . . Kepler searches for planets by measuring the tiny dip in brightness that occurs when an object passes in front of, or transits, a star.

http://www.irishtimes.com/news/science/space-telescope-discovers-nine-earth-like-planets-1.2642770