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Location: Chemistry/Physics Building, MUN
Time: 8:00 pm
Present: 28
1. Randy's Introduction.
2. Observing.
Randy Dodge showed us a newspaper article from Lewisporte. Jim Gillard has finished his observatory. Inside the dome he has a Meade 12" LX200. The dome is about 10 feet in diameter, and is situated next to his house. The telescope rests on a 5x5 ft. pillar, which is 25 ft. high (sunk into the earth).
Gary Case explained how the north magnetic pole wanders, to answer a question from last month.
3. Chris Stevenson on the Space Shuttle. Various ideas and theories were discussed. There was a good back and forth on a number of Shuttle related topics, including possible replacements. Fred noted that Guigné space will have to wait for shuttle flights to resume before their payload (was to be in the next few flights) will be able to go up.
4. What's Up by Gary Case. Saturn and Jupiter are easily visible. They are going through a retrograde motion right now. Venus and Mercury are visible in the morning, so is Mars. For deep sky objects, Leo is well situated. Some examples would be looking for the Virgo galaxy cluster.
5. Fred Smith. Harvard College Expedition to St. John's for the 1761 transit of Venus. This was probably the first American scientific expedition, lead by John Winthrop of Harvard.
Fred started by showing us some books that cover some early history of Newfoundland. These are examples of some of the sources he used to track down information on the transit expedition. Some examples are: The Pursuit of Science in Revolutionary America (which refers to the transit), Venus in Transit, by Eli Maor, and Judge Prowse's history of Newfoundland (he does refer to John Winthrop). One key point to keep in mind is that all the sources agree that most of the trees around the harbour, out to a distance of 6 or more kilometers were completely removed.
Fred explained just exactly what a transit of Venus is supposed to be. Tycho Brahe and Kepler did the early work. Jeremiah Horrox was the first to observe the transit. He determined the angular size of Venus in 1639. His friend William Crabtree also measured this independently. Fred showed a picture of Crabtree being transported in wonder "in a womanish fashion".
Transits were shown to occur in a cycle 243 years, with 8 years between the doubles, and pairs of doubles being separated by 105 and 121 years. Horrox, who only lived to 22, predicted the further transit of 1639, 8 years after Kepler's 1631 prediction, and much earlier than the erroneous 120 year wait predicted by Kepler, who missed out on the doubling business.
The 1761 transit had 70 or more stations around the world, in what was probably the first international scientific endeavor. The 1769 transit was of course the one Capt. James Cook travelled to Tahiti (O'Taheti) to observe. Halley had impressed upon the world that transits of Venus were much more important than transits of Mercury in order to determine the astronomical unit. Due to a number of his papers, the 1761 and 1769 expeditions were set up after his death. Halley worked out how viewing and timing a transit from different locations of the earth (allowing you to determine the angular separation between the tracks of Venus), along with Kepler's Third Law, would allow a determination of the Astronomical Unit. Fred explained roughly how this was done.
Another explanation, somewhat similar, can be found at: http://www.dsellers.demon.co.uk/venus/ven_ch1.htm .
John Winthrop of Harvard College knew that part of the transit would be visible from Newfoundland, so he set up an expedition, with funds and instruments from the Province of Massachusetts and Harvard College. He left in the Province-sloop Massachusetts, along with two students. Crucial to determining his location in St. John's were a few comments indicating they had set up on an eminence some distance from the harbour. There were "swarms of insects, that were in possession of the hill". This makes it unlikely to be a coastal location. It took a number of days to bring/set up their gear, and they also built a platform, driving stakes into the ground. On the day, the sun rose from behind a cloud, but they got to view most of the transit.
Fred asked, where was this eminence? Although Winthrop indicated the local gentlemen called his location "Venus Hill", this was not to be found on maps in any time period. It is also unlikely they would not have mentioned their location if it were an already recognized name, such as "Signal Hill". According to Simon Newcomb, the local Harbormaster thought the location must be Fort Townshend. Unfortunately, that location is ill-situated for a good view of the horizon.
Fred took Winthrop's latitude, and assuming an error of one mile, found only four decent sites in the topographical maps (the given longitude is actually out at sea). The South Side hills is outside of this zone, and also lacks suitable terrain for driving posts, much less clambering up the hills with equipment. Surely, if they set up on Signal Hill, they would have stated so. That leaves three suitable areas, roughly around Kenmount Hill (for instance Firewood Hill). The stated latitude also happens to go through Kenmount Hill. In those days, much of the lower path should have been denuded of trees, and the ascent is pretty gradual. The ground is good for pole-driving, and particularly from Kenmount, there is a good view of the sea horizon where the sun would have risen. All three sites are possibilities, but the very top of Kenmount would seem to have been an ideal location.
Placing a plaque on Kenmount Hill is somewhat problematic. Fred doubts it would remain there over time. The RASC History Committee is working with the IAU to commemorate all the 1761 transit sites with plaques. They agree with Fred that probably the most practical site for a plaque would be in the Rooms.
6. Coffee Break.
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