The important day of the observation was now approaching, and everything was in readiness.  In order to diminish the risk of disappointment through local atmospheric disturbance, Cook sent a party to Eimeo (York Island), and a second one to the south-east of Otaheite, as far to the east of Point Venus as possible.  The first party consisted of Lieutenant Gore, Banks, Sporing, and Monkhouse, and the second of Lieutenant Hicks, Clerke, Pickersgill, and Saunders, Mr. Green providing the necessary instruments.  At Fort Venus everything was in good working order.  The astronomical clock was set up in the large tent, being placed in a strong frame made for the purpose at Greenwich, and was then planted in the ground as firmly as possible and fenced round to prevent accidental disturbance.  Twelve feet away the observatory was placed, comprising the telescopes on their stands, the quadrant securely fixed on the top of a cask of wet sand firmly set in the ground, and the journeyman clock.  The telescopes used by Cook and Green were two reflecting ones made by Mr. J. Short.

“The 3rd of June proved as favourable to our purposes as we could wish.  Not a cloud to be seen the whole day and the air was perfectly clear, so that we had every advantage we could desire in observing the whole passage of the Planet Venus over the Sun’s Disk.  We very distinctly saw the atmosphere or Dusky Shade round the body of the planet, which very much disturbed the time of contact, particularly the two internal ones.  Dr. Solander observed as well as Mr. Green and myself, and we differ’d from one another in observing the times of contact much more than could be expected.  Mr. Green’s telescope and mine were of the same magnifying power, but that of the Doctor was greater than ours.  It was nearly calm the whole day, and the thermometer exposed to the sun about the middle of the day rose to a degree of heat we have not before met with.”

In the report published in the Philosophical Transactions he also refers to the heat: 

“Every wished-for favourable circumstance attended the whole of the day, without one single impediment excepting the heat, which was intolerable; the thermometer which hung by the clock and was exposed to the sun, as we were, was one time as high as 119 degrees.”

This report is accompanied by diagrams illustrating the different contacts and the effects of the penumbra, which Cook believed was better seen by Solander than by himself or Green.  It was estimated at about seven-eighths of the diameter of the planet, and was visible to Cook throughout the whole Transit.

The times taken by Green were: 

The first external contact:  9 hours 25 minutes 42 seconds A.M. 
The first internal contact:  9 hours 44 minutes 4 seconds A.M. 
The second internal contact:  3 hours 14 minutes 8 seconds P.M. 
The second external contact:  3 hours 22 minutes 10 seconds P.M.

The other two parties were equally successful, and at times Banks was able to employ himself in trading with the natives, with whom he soon got on friendly terms; in fact, he had to decline further purchases as he had as much as they could take away with them.  He was also successful in his botanical enquiries, obtaining several plants he had not seen in Otaheite.