Interesting that the subject here is mostly about the accurate measurement of time and that Tycho does not seem to think clocks sufficiently accurate for his purpose. He goes through ideas for using mercury falling through a small hole but notes that it is not very accurate. So how was he keeping accurate time? Terence Tao does not know too much about clocks as he questions the accuracy of Cook's clock which is a silly mistake since Cook's clock was accurate to seconds a day and has been famous ever since. We have four Russian marine chronometers here restored by us and running at a constant minus 3 seconds a day rate. Perhaps many people do not really comprehend exactly what Tycho was doing on his island. Years of accurate records of the position of an object at a given time from a known position. One thing that I like about his style here is the lack of the kind of sneering scientific pomposity that we have to endure form math students ( and doctors) today.
I’m not sure if Cook had Harrison’s clock or what, but I’ve got some reservations about Cpt. Cook’s story in general. However, Harrison’s clocks were a far cry from what was available to Tycho. If you’ll note he’s talking about them being weight driven. So a cord is wound up on a spool. (i think) So the radius of the cord and the spool will shrink as the cord unfurls which would, according to him, have an effect on its accuracy.
But, yes that was the salient feature of the post. How many times do you hear that Tycho was ill equipped and therefore could not make accurate observation? They were close but no cigar!
Which is amazing when you think about it since Tycho’s value for the length of the year is EXACTLY the same as we use today:
AI says Tycho complained that his four clocks were out by 4 seconds a day. I wonder if it knows exactly where that quote came from. Did he really say that. It sounds like him. Land based clocks were much more accurate much earlier than sea clocks. This was because they were heavier, did not move, were adjustable. I am trying to find out if any of his clocks survive. H1 that cook had a copy of was a watch and accurate to a few seconds a day. Tycho could use the stars to get ultra accurate midnight fixes and so know if his clocks were accurate over 24 hours. The usual way this is done is to average four or five clocks. I am inclined to think he must have had very accurate clocks. Buts clocks at that time suffered from temperature changes and less than fully accurate gears and a few other problems with materials and bearings. Reading his work in your posts it is obvious he was highly precise. He obviously wanted to know exactly where a planet or star was at a precise moment over decades. That was the priceless data that he was after. How can we even begin to understand what is going on without accurate observations over time. Good stuff. Thanks for the posts.
Interesting that the subject here is mostly about the accurate measurement of time and that Tycho does not seem to think clocks sufficiently accurate for his purpose. He goes through ideas for using mercury falling through a small hole but notes that it is not very accurate. So how was he keeping accurate time? Terence Tao does not know too much about clocks as he questions the accuracy of Cook's clock which is a silly mistake since Cook's clock was accurate to seconds a day and has been famous ever since. We have four Russian marine chronometers here restored by us and running at a constant minus 3 seconds a day rate. Perhaps many people do not really comprehend exactly what Tycho was doing on his island. Years of accurate records of the position of an object at a given time from a known position. One thing that I like about his style here is the lack of the kind of sneering scientific pomposity that we have to endure form math students ( and doctors) today.
I’m not sure if Cook had Harrison’s clock or what, but I’ve got some reservations about Cpt. Cook’s story in general. However, Harrison’s clocks were a far cry from what was available to Tycho. If you’ll note he’s talking about them being weight driven. So a cord is wound up on a spool. (i think) So the radius of the cord and the spool will shrink as the cord unfurls which would, according to him, have an effect on its accuracy.
But, yes that was the salient feature of the post. How many times do you hear that Tycho was ill equipped and therefore could not make accurate observation? They were close but no cigar!
Which is amazing when you think about it since Tycho’s value for the length of the year is EXACTLY the same as we use today:
365d, 5h, 48m, 45sec.
-circa 1580’s, more than 400yrs ago.
AI says Tycho complained that his four clocks were out by 4 seconds a day. I wonder if it knows exactly where that quote came from. Did he really say that. It sounds like him. Land based clocks were much more accurate much earlier than sea clocks. This was because they were heavier, did not move, were adjustable. I am trying to find out if any of his clocks survive. H1 that cook had a copy of was a watch and accurate to a few seconds a day. Tycho could use the stars to get ultra accurate midnight fixes and so know if his clocks were accurate over 24 hours. The usual way this is done is to average four or five clocks. I am inclined to think he must have had very accurate clocks. Buts clocks at that time suffered from temperature changes and less than fully accurate gears and a few other problems with materials and bearings. Reading his work in your posts it is obvious he was highly precise. He obviously wanted to know exactly where a planet or star was at a precise moment over decades. That was the priceless data that he was after. How can we even begin to understand what is going on without accurate observations over time. Good stuff. Thanks for the posts.
Very readable and much to the point. Thanks for the post.