June 5th, Venus will apparently transit the sun. The event will last long enough for the everyone on Earth to observe it... For anyone in the know, I've not done much reading on this, but would astronomical events such as this have provided an opportunity for timing calculations for determining longitude?
I definitely plan to watch this from my filtered total station and my (new to me) Kern DKM1 projecting on a card.
Done in the 1890s in Mauritius (Island in the Indian Ocean) and in Egypt. The one in Egypt is their origin point for their national horizontal geodetic datum. I think it was also done in the Union of South Africa at the same time, as well as in Hyderabad, India. (All of these were in the British Empire at the time.)
There is a Trig Station on Kauai called "Transit of Venus". It must have been done during the last transit pair of 1874 & 1882, which makes sense as this is the time period when the Hawaiian lands went from the Monarch to private ownership and there was a lot of surveying going on.
Projecting the image with a transit will work great, but be really careful pointing an electronic total station at the sun. You did say you had a filter, but I wanted to caution everyone else.
> Projecting the image with a transit will work great, but be really careful pointing an electronic total station at the sun. You did say you had a filter, but I wanted to caution everyone else.
A pair of binoculars mounted on a tripod will do as well, if not better than a transit. Just leave one of the lens caps on. You can project and focus a very large image. Venus appears as a small dot against the sun's background.
JBS
Transit of Venus and determination of longitude
to save y'all the trouble of looking it up, here's the wiki link
Observations of this transit had very much to do with assisting in the determination of longitude during the time when that problem was very much the most important consideration in marine navigation. Captain James Cook's first voyage of discovery in 1769 had this as one of it's main goals.
Captain Cook and the Transit of Venus
It was important that Venus Transit observations occur simultaneously in widely separated points on the globe. During the 1761 and 1769 Venus transits, our surveying friends Mason & Dixon also participated near the Cape of Good Hope.
Other information is available in Dava Sobel's book Longitude
and J.E.D. Williams From Sails to Satellites
Fascinating subject for all who are keen on navigational and geodetic survey science. Thanks for bringing it up Shawn.
Transit of Venus and determination of longitude
I am in Houston airport, en route to Ecuador. Unfortunately I am returning on 6/4, too early to see it there. I will be trying to take a picture on the equator. I took one years ago at Greenwich (0 longitude), this will complement that!
And, another coincidence, as I was leaving the house I grabbed the book "The Stargazers", about Mason and Dixon. I am just starting to read it again, but as I recall it goes into some detail about their trip to observe the venus transit.
Actually, we (5 of us, family) should be on final approach to Quito right about now (arriving 9 PM central time), but we missed the connection in Houston, so now we are going to Bogota (leaving at midnight), then to Quito in the AM.
Transit of Venus and determination of longitude
> And, another coincidence, as I was leaving the house I grabbed the book "The Stargazers", about Mason and Dixon. I am just starting to read it again, but as I recall it goes into some detail about their trip to observe the venus transit.
>
> Actually, we (5 of us, family) should be on final approach to Quito right about now (arriving 9 PM central time), but we missed the connection in Houston, so now we are going to Bogota (leaving at midnight), then to Quito in the AM.
Mr Hamilton, all the best to you and your family, sounds like an adventure for all of you in South America. Never been to Ecuador myself, but spent plenty of time in Venezuela and Colombia. Puerto Assis in Colombia was the closest I got to Ecuador, but that was close enough. Bogota was once one of my favorite cities until things started blowing up there with too much regularity.
As for Mason and Dixon, I see the tag line in your signature, and offer this:
I live in the Pacific Northwest (US). Our chances of seeing the sun that day, much less the transit of Venus, are about 50%. During the winter, it is often single digit %.
🙁
Pittsburgh isn't the sunniest place either, but probably not as bad as the PAC NW.
> Pittsburgh isn't the sunniest place either, but probably not as bad as the PAC NW.
Depends on which side of the Cascades you are on. No shortage of sunshine here on the dry side.
