This month the planet Venus will cross the face of the Sun in one of the solar systems rarest events. Transits of Venus only occur in either early June or early December, at these times the orbital nodes of Venus pass across the face of the Sun. If Venus reaches inferior conjunction at one of these times, a transit will occur. Transits of Venus occur in a pattern, with intervals of 8, 121.5, 8 and 105.5 years. The last one occurred on Dec 6th 1882, with the next one occurring on June 6th June 2012.
There are 5 events of special interest during the transit, the first is when the edge of Venus touches the visible edge of the Sun (External Ingress) this occurs just before 06:20 (BST). Around 20 minutes later the second event occurs, this is the point when the entire disc of Venus is on the disc of the sun. It is at this point when the phenomenon known as the black drop can be seen. At 09:22 Mid Transit occurs. At 12:04 the leading edge of Venus touches the edge of the Sun, another chance to observe the black drop effect, by 12.24 the disc of Venus will have left the face of the Sun and the event will be over. The Bristol Astronomical society will be holding a public event in Castle Park to observe this rare event Add link to the bit that is already on there.
More information about transits can be found on Fred Espanek's website at http://sunearth.gsfc.nasa.gov/eclipse/eclipse.html
| Event | Time BST | Sun's Alt |
| External Ingress | 06:19:54 | 10° |
| Internal Ingress | 06:39:49 | 13° |
| Mid Transit | 09:22:47 | 38° |
| Internal Egress | 12:04:10 | 59° |
| External Egress | 12:23:42 | 60° |
The Transit of Venus, The BBC and The Bristol Astronomical Society
Most of you already know that we were asked by a BBC TV production company recently to take part in a documentary film which is aimed at recording this month’s transit of Venus,
The initial camera work was carried out on Thursday May 6th at Castle Park, Bristol and with a clearing sky 17 of our members with 6 small telescopes and solar projecting gear were able to demonstrate how astronomers will observe and record this very rare event. We were very ably assisted by a group of enthusiastic young people from Stockwood Green Primary School and their science teacher Mrs Penny Warner.
The children enacted the transit with suitable large beach balls together with a splendid commentary by Adam Hart-Davies, Popular TV presenter. Dr Lucie Green from Cardiff University, a solar scientist, was also present to make sure technical matters were right.
We are looking forward to being part of the BBC documentary film to be shown in two parts. The programme be on Saturday 5th June at 5 PM on BBC 2 (30 Minutes) and on Tuesday 8th June at 11:30 PM on BBC 2 (1 hour). There will also be a series of short live inserts on BBC 1 on the morning of 8th June at 7:30, 8:30, 10:00 am and 12:00 noon.
The programme “Stardate; The Transit of Venus” is being produced for the Open University and the BBC. It will link events in Much Hoole near Preston where the transit was first seen by Jeremiah Horrocks in 1639, and Egypt where astronomers will be observing under good conditions, including a party of our own members from Bristol.
“The Transit of Venus” is the first in a series of astronomy programmes, which the OU/BBC will be broadcasting over the next year under the title “Stardate”.
High-resolution pictures can be downloaded at the following website:
http://www3.open.ac.uk/media/image-bank/programmes.asp
We shall be meeting in St Peters Square; Castle Park near the Galleries shopping centre, Broadmead from 6:30 am to 1 PM with telescopes to observe the event at this site, licensed to us by Bristol City Council.
John Meacham. Director of Observations, Bristol Astronomical Society