After launching the Iridium-2 mission on June 25, 2017, the first stage of the SpaceX Falcon 9 is seen here coming in for a landing on the “Just Read the Instructions” drone ship that was positioned in the Pacific Ocean. (SpaceX, Flickr/Creative Commons)
An exhibitor shows a skull model with 3D modeled prostheses during the FabCon 3.D and Rapid.Tech international fairs in Erfurt, Germany on June 20, 2017. (AP)
U.S. Vice President Mike Pence is seen here with NASA’s 12 new astronaut candidates at NASA’s Johnson Space Center in Houston, Texas on June 7, 2017. NASA waded through its biggest applicant pool ever to select seven men and five women for its astronaut corps. (NASA via AP)
People visiting the China Beijing International High-Tech Expo in Beijing, June 10, 2017, are seen here looking at a mockup of China’s homegrown Beidou satellite navigation system. (AP)
NASA successfully launched a sounding rocket from its Wallops Island Flight Facility in Virginia on June 29, 2017. NASA says the rocket flew to an altitude of about 191 km when it deployed a canister containing chemicals that will be used in ionosphere or Aurora sounding rocket missions. This photo shows how the chemicals lit up the night skies along the U.S. East Coast (NASA)
Excitement is building in anticipation of a rare event taking place on August 21, 2017. That’s when a total eclipse of the Sun will make its way across the continental United States from Oregon to South Carolina. The last time at least part of the U.S. experienced a total solar eclipse was back in 1979 when one passed over several Northwestern States. Seen in this June 12, 2017, photo, is an advertisement of the astronomical event. (AP)
Researcher Eva-Maria Geigl is seen in this photo dated June 16, 2017, working in her Monod Institute laboratory in Paris. Geigl recently conducted a DNA study, which looked back thousands of years to gain new insight into the domestication of one of the world’s favorite pets, the cat. (AP)
The Belgian Punch Powertrain Solar Team showed off their new solar car “Punch 2” at the Planckendael Zoo in Mechelen, Belgium on June 21, 2017. The team will compete in the Bridgestone World Solar Challenge to be held in Australia in October (AP)
People watch as Indian Space Research Organization’s (ISRO) Polar Satellite Launch Vehicle carrying the 712 kg Cartosat-2 Series Satellite along with 30 co-passenger satellites, blasts off from the Satish Dhawan Space Centre in India, June 23, 2017. (AP)
This is a video screenshot captured on June 8, 2017, of China’s Canbot robot as it performs at the Shanghai CES electronic show in Shanghai, China. (AP)
When James Cook left England his main orders were to get to Tahiti ASAP and calculate his Latitude (which was more important than Longitude). He rounded Cape Horn which would have been no small feat. I think he lost a few men doing it. So he set up on what was to become “Point Venus”. He also had Harrison clocks so he could calculate longitude. The exercise was supposed to be as follows:- There were to be 3 positions on Earth observing the Transit of Venus. “North Cape”,Norway; Tahiti, and somewhere in Canada ? Each observer was to point to Venus ‘hitting’ the rim of the Sun; the moment Venus was fully in the Sun’s rim and the same as when Venus was exiting the Sun.
There were difficulties as various ingoing and outgoing parts of Venus was ‘fuzzy’. They still came up with rough idea of 1 Astronomical Unit, or the average distance from the Earth to the Sun. ## Also, I think Green, the astronomer, must have had astronomical tables for the Moon.
Surely, most of the Stars in the Southern Hemisphere would be unkown to James Cook and his astronomer.
Cont’d from above
The points chosen to sight to Venus were as far apart as possible. Latitudes were the main things required. So the latitude at Tahiti would have made an angle with somewhere in Canada (?) as well as “North Cape”,Norway. Also the latitude of the point in Canada (?) would also have made an angle.
So there were 3 points on Earth pointing to the same spot where Venus just touched the Sun; then wholly inside the rim of the Sun. Then observations would have been made as Venus exited the Sun.
Even though the Earth rotated it didn’t matter as Latitude was the main factor when pointing to the Transit of Venus.
So the main reason that Cook went to Tahiti was for the observation of the Transit of Venus. The Astronomical Unit, AU, was required so distances to the Sun;Venus; and other planets could be calculated.
Cook discovered New Zealand because he saw ‘Large White Clouds’. He chartered most of the coastline. He MUST have had tables on Moon, as most/all the stars above would be unknown. I think Green , the astronomer, must have had tables. After New Zealand, he would have known if he stuck to a certain Latitude he was sure to strike Tasmania or Australia. WA had been already ‘chartered’ for Latitude anyway, as there were many ships wrecked in WA.
Of course, Cook was the first (?) to insist everybody eat sour-krout which stopped scurvy.