Venus, Exhibition, TRANSIT, ISS, Weblinks, Bridge name, Dick Gordon, Solarfest

Hi all,

 

1. Venus disappearing: Never mind 'Where's Wally?' - Where's Venus? Not so long ago, Venus was a brilliant unmistakable beacon in the W evening sky. Now you need to look carefully and quickly low down in the bright NW twilight about 20-30 mts after sunset. The reason of course is that Venus is hurrying to its date with the Sun on 6 June: the last Transit of Venus until December 2117. See below for details of that.

  But if you want a challenge, on 1 June try to spot it one last time before the transit. And you will get extra points if you also manage to spot Mercury very close by that evening: as Venus moves in closer to the Sun, Mercury is moving out. But both will be very low down, and will set when the sky is still quite bright, so you will need binoculars, and fainter Mercury will be quite a challenge.

   Venus will be a very thin crescent, only 7% illuminated, and magnitude -3.9, Mercury will be nearly 'Full', as it is on the far side of the Sun, and much fainter at mag -1.6.

   The following details apply to Greater Belfast: if you live much further West and/or South, add 5 or 10 minutes to these times.

 At 22.10 BST, look at an azimuth of 312 degrees, just to the left of where the Sun has set. Venus will be at an altitude of 1 deg 51' (almost 4 moon diameters), and tiny Mercury will lie almost directly above it, at 00.30 on a clock face, at a distance of just over 13 arcminutes: that's a bit less than half the diameter of the Moon.

   By 22.15 Venus will have dropped to an altitude of 1 deg 27', with Mercury's alt = 1 deg 39'. At 22.20, Venus will be down to an altitude of 0deg 58' (about 2 moon diameters), with Mercury above it at alt = 1deg 11'. If the sky is exceptionally clear, you might even spot them at 22.25, when their altitudes are 0deg 31', and 0deg 44', respectively.

   You will need a very clear NW horizon and good binoculars or a telescope, but DO NOT LOOK while the Sun is still above the horizon!

 

2. Transit of Venus Exhibition at Armagh Observatory:

The Armagh Observatory is presenting a special exhibition to mark an exceptionally rare astronomical event, namely the Transit of Venus which will be visible from Northern Ireland (weather permitting) for a short
time on the morning of Wednesday 6 June. During such a transit, the planet Venus passes directly between the Earth and the Sun, appearing as a small black circle taking several hours to cross the Sun.
   This year's transit is the last visible from Earth for more than a hundred years. The exhibition to mark the event comprises items relating to the history of transits of Venus including items from the Observatory's
archives and the King George III Collection. Further details can be found at the web-site http://star.arm.ac.uk/venustransit/exhibit/.
   The exhibition will be open, free of charge, from 10:00--11:00 and 15:00--16:00, Monday to Friday, from Friday 1 June to Tuesday 12 June inclusive.  Groups of more than six persons are requested to contact the
Observatory in advance: Tel: 028-3752-2928; E-mail: jmf@arm.ac.uk.

3. The TRANSIT OF VENUS, 6 June: This is the last Venus transit visible anywhere in the world until 2117. Transits usually occur in pairs separated by 8 years, with a gap of over a century until the next pair; the first one of the present pair occurred in 2004.  However, 'single' transits do rarely occur: the next one will be in 3089, i.e. there will be none in 3097. It is the most central transit since 1639, with Venus passing 9' 13" from the centre of the Sun at mid-transit at 01.28 UT (that moment is not visible from Ireland, as the Sun will still be below our horizon), and that record won't be exceeded until 2255.

   Maximum visibility of the event in Ireland will be from the NE part, where the sun rises earliest. But in theory at least part of the transit will be visible from all of the island of Ireland, although from the far SW it will be just about over at the moment of sunrise. Intermediate locations may get a brief view if you have a perfectly clear NE horizon right down to the theoretical level at the time of sunrise. In approximate terms, the altitude of Venus, as seen on the solar disc, at 3^rd contact (the start of the planet's exit off the disc) are: Dublin = 4.0˚, Cork = 2.2˚, Galway = 2.6˚, Limerick = 2.4˚.

   The apparent diameter of Venus during the transit will be 57.8" (arcsecs); just below the limit for naked eye visibility, so some sort of optical aid will be required. NOTE: All the usual safety advice applies when observing this transit: i.e. do NOT look at the Sun directly with anything except proper solar filters on either telescope or binocs, or by projecting the image through a telescope on to a piece of white card. See www.irishastro.org for details.

 The following times are given in BST. Time of 3^rd Contact in N. Ireland = 05h 37m 03s.  Time of 4^th Contact (end of the transit) = 05h 53m 14s.  The effects of refraction on both the Sun's and Venus' altitude and the various timings have been taken into account. 

    NB: Sunrise is the time when the upper limb of the Sun first comes above the theoretical horizon. But the transit will not start to become visible at this time, as Venus will be a bit below the upper limb of the Sun. So to calculate the visible duration, we must start from the time of 'Venus rise', not sunrise. Venus will transit across the N third of the Sun's disc, and will be exiting at the NW (top right) of the disc, after which it will cease to be visible.

   OBSERVING SITES: I have checked about a dozen possible observing sites in NE Co Antrim, with the recommendation below. (Skerries, Co Dublin, is in effect the best site in ROI, although the tip of the Cooley Peninsula is marginally better than Skerries, but not enough to justify a long journey).  

   Note also that the time of first visibility of the Sun and Venus will depend on the altitude of the actual local NE horizon. For sites near Fair Head and Torr Head, that's the Mull of Kintyre in Scotland, (reaching 446m above sea level), and beyond it the Isle of Arran, which reaches 874m. So actual local sunrise from those sites will be delayed by several minutes. Those mountains might also attract a covering of cloud, delaying visibility of the Sun and Venus by several minutes, or even longer.

   APPEARANCE ON THE SUN'S DISC:  Venus will appear in the NE sector of the Sun's disc. At the moment of Venus rise it will be about 1/10 of the Sun's diameter from the Sun's limb. From then on that distance will decrease as the transit progresses to its end.

   OBSERVING SITE: All factors considered, the best option seems to be Garron Point, between Carnlough at Glenarriff/Waterfoot, where there are two suitable car parks within 0.2 miles, with the option to move to the higher site at nearby Tower Rd if there is a sea fog. NB: There is no car park on Tower Road, but there are two areas where one could park safely along the roadside (as there will be no traffic there at that time of the morning), with clear views to the NE: these are at 0.9 miles and 1.0 to 1.1 miles from the junction of the south end of Tower Road with the main A2 road. This is at N55˚ 01' 49", W 5˚ 58' 21", 3.5m N of Ballygalley Castle Hotel.

    WEATHER: Apart from the risk of cloud, there is also a slight chance of a sea fog. All the sites along the A2 coast road are vulnerable to that. Two suitable higher sites are available: Tower Road, above Garron Point (alt 70m), and the car park at the summit of Ballycoose Rd, above Cairncastle (alt 270m).

   TIME: If you want to set up cameras and/or a telescope, you should be ready to image / observe by about 04h 40m – 04h 45m BST, so arrive in plenty of time. Orient your instruments to the NE (approx. azimuth of 46˚), and look for the first glimpse of the Sun. Look 20˚ left of Ailsa Craig (a prominent conical island on horizon).

   EATS: We will celebrate (or commiserate if cloudy) with a fry-up at the site after the event, so bring some suitable grub, plus a portable BBQ or gas stove, frying pan etc.

N.B. This event occurs at sunrise on the 6th, so it's the night of 5-6 June!

 

4. ISS. The ISS has started another series of morning passes over Ireland. Because of the approach of midsummer, with almost continuous twilight through the night, these morning passes will gradually merge into a series of evening passes in early June, and it will continue to be visible here well into mid-late June. Details are on the excellent free site www.heavens-above.com  

 

5. Apollo 12 Command Module Pilot Dick Gordon will be attending two public events in Glasgow on Wednesday 17 October 2012. There will be an event in Blackfriars at 11am and in Glasgow Caledonian University at 7.30pm. Tickets for both events include a complimentary autograph from Captain Gordon. Full details are on the website www.walkwithdestiny.com and tickets can be purchased on the website too.

Best wishes, Aileen Malone, www.walkwithdestiny.com, 01236 766970

 

6. INTERESTING WEBLINKS: NASA time-lapse shows Lyrid meteor shower from space - as well as the Aurora Borealis and lightning strikes hitting the earth.

Mystery of Mars's organic carbon deepens - meteorites from Red Planet DID carry building blocks of life | Mail Online

The hunt for Planet X is back on: Noted astronomer calculates planet four times size of Earth must exist on fringe of solar s.

 

Britain must build spaceport to avoid being 'left behind' in the tourism space race, business leaders claim | Mail Online

 

A New Count of Potentially Hazardous Asteroids - NASA Science

 

The new space race heats up: Russia plans 'permanent' bases on moon | Mail Online

7. A BRIDGE FOR PHYSICS: "The Walton Bridge petition". The Institute of Physics (IOP) Ireland is campaigning to have the new bridge across the Liffey in Dublin at Marlborough Street named for ETS Walton - Ireland's only physics Nobel prize-winner. Please sign our petition to Dublin City Council via the link at http://www.iopireland.org/news/12/page_55296.html. (via Peter Gallagher)

8. Dunsink Solarfest, 23 June. Following on from the success over the last 3 years, IFAS in conjunction with Dublin Institute for Advanced Studies (DIAS) www.dias.ie and Trinity College Dublin www.tcd.ie are organising a one-day event in Dublin to celebrate solar astronomy. Solarfest 2012 will take place on Saturday 23rd June at Dunsink Observatory, Castleknock, Dublin. IFAS are very grateful to DIAS and TCD for supporting the event and entry is FREE.
   The programme for the event is currently being finalised and will be updated in due course on the IFAS website www.irishastronomy.org However, the event will feature a number of lectures, a workshop, solar observing (weather permitting) and more. The lunchtime break will allow an opportunity to take in a tour of the facility to see the observatory and the 12" Grubb refractor. Tea/coffee will be provided, however please bring your own lunch.
  Spaces are limited to 60 seats. If you are interested in attending, please send an e-mail to ifas.solarfest@gmail.com. Please state in the e-mail how many seats you would like to reserve.
  Regards & Thanks, Michael O'Connell

(NB: Dunsink Observatory is on Dunsink Lane, Castleknock, Dublin. The Observatory is at 53 deg 23' 14.3"N, 6 deg 20' 19.0" W, with the entrance off Dunsink Lane at 23' 16.6"N; 20' 14" W. But Dunsink Lane has been blocked on the city side, and the observatory is now only accessible from the New River Road end, off the Navan Road, near the junction of the N3 and the M50 - the Castleknock junction, Junction 6. Since the M50 upgrade this has become a very complex junction.

    If approaching via the M50 from the Dublin airport direction, you MUST get into the correct lane at the offslip, or you'll be way off course! So when you approach Junction 6, move onto the offslip lane (to the left, obviously), but then stay on the two right hand lanes of the offslip, signed for 'Castleknock'. Do NOT keep on going round to your left via the left hand lane on the offslip, which will take you on to the N3 and Castleknock village! (That seems wrong when you know where Dunsink is, but believe me - I learned the hard way! If your Satnav says something else, ignore it.)

    Then move into the left hand of the two 'right' offslip lanes (in other words, the middle one of the three). This will bring you to the original roundabout, with traffic lights, where you then keep left, and then immediately left again, signed for 'Dunsink'.

   This road leads directly on to New River Road. At the 'cul-de-sac' sign continue on straight, and it becomes Dunsink Lane. Go straight on for almost 2 km (past Elmgreen Golf Course) until you see the road blocked ahead of you: the entrance to the Observatory is on the right just before the block. 

   If you go this way, it's simple and easy, so don't be put off - just follow those directions exactly.

On the return journey you go back along Dunsink Lane, then follow signs for the M50 Northbound. (TM)

 

9. TWITTER: the IAA now has a twitter account. twitter@IaaAstro

 

10. BBC THINGS TO DO WEBSITE: See the forthcoming IAA events on  

http://www.bbc.co.uk/thingstodo

 

11. JOINING the IRISH ASTRONOMICAL ASSOCIATION is now even easier: This link downloads a Word document to join the IAA. http://irishastro.org.uk/iaamembership.doc. 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.  See also www.irishastro.org. 

 

Clear skies,

Terry Moseley