Post APdkOclDGxH08yHUeW by bthalpin@mastodon.social
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 (DIR) Post #APdkOclDGxH08yHUeW by bthalpin@mastodon.social
       2022-11-15T21:17:27Z
       
       0 likes, 1 repeats
       
       At sunset, how far east of overhead does a satellite need to be to be invisible?#+begin_src emacs-lisp :exports results(defun angle-inv (elev)  (let* ((earth-radius 6371.0))    (/ (* (acos (/ earth-radius    (+ earth-radius elev))) 180) pi)))(defun saywhere (elev)  (format "At %dkms, %1.1f degrees.\n" elev (angle-inv elev)))(mapcar 'saywhere '(408 550))#+end_src#+RESULTS:| At 408kms, 20.0 degrees. || At 550kms, 23.0 degrees. |