Kepler's Laws of planetary motion

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
4 replies · 2K views
Erenjaeger
Messages
141
Reaction score
6
Whose observations did Kepler use to prove that planets do in fact orbit in ellipses ?? Was it Tycho's observations?
Thanks.
 
Astronomy news on Phys.org
Erenjaeger said:
Tycho's observations
You really have to hand it to those early astronomers. Everything was measured using the naked eye and some very crude instruments. No Go-To telescopes available in those days. I guess the only thing on their side would have been No Light Pollution. (Put that candle out!)
Respect.
 
  • Like
Likes   Reactions: russ_watters
I don't think I would use the word "crude" to describe Tycho's Great Equatorial Armillary that he used to gather the observations that Kepler used. See the attached drawing. It was 3 meters in diameter and accurate to approximately 1 minute of arc. Of course we can do much better today, but for the time it was a very well designed and impressive instrument.
 

Attachments

  • tycho_inst6.gif
    tycho_inst6.gif
    99.1 KB · Views: 691
phyzguy said:
I don't think I would use the word "crude" to describe Tycho's Great Equatorial Armillary that he used to gather the observations that Kepler used. See the attached drawing. It was 3 meters in diameter and accurate to approximately 1 minute of arc. Of course we can do much better today, but for the time it was a very well designed and impressive instrument.
The word "crude" was comparative and not intended to offend anyone. I wouldn't mind betting that Keppler himself would have used the word if he could see what we use now.
One minute of arc is, in some respects, a barn door. The accuracy of clocks (time is as important as angle) was not good and I would reckon that accuracy of measuring long baselines would also not be very special.
No.They did a great job with what they had to hand.