[HN Gopher] The Carte du Ciel attempted to map the sky without c...
       ___________________________________________________________________
        
       The Carte du Ciel attempted to map the sky without computers
        
       Author : kergonath
       Score  : 28 points
       Date   : 2022-09-12 11:38 UTC (1 days ago)
        
 (HTM) web link (arstechnica.com)
 (TXT) w3m dump (arstechnica.com)
        
       | [deleted]
        
       | ortusdux wrote:
       | "The Memory Palace", one of my favorite podcasts, does a touching
       | ode to the women behind this operation.
       | 
       | https://thememorypalace.us/400000-stars/
        
         | eesmith wrote:
         | That's a different project. The podcast episode concerns
         | Pickering and his group at the Harvard College Observatory, in
         | the US.
         | 
         | This operation was the Carte du Ciel. As the article says:
         | 
         | > Although Pickering from Harvard was at the meeting, no
         | American observatory chose to participate in the survey. The
         | Americans thought a shallower, faster survey might be good
         | enough, rather than the monumental work proposed in Paris, and
         | they were suspicious of large, centrally organized projects.
        
       | londons_explore wrote:
       | Why was it important to measure the positions of the stars and
       | write them all down?
       | 
       | Surely just keeping the plate is sufficient information... If you
       | ever need to see what a star looked like, you can still look back
       | at the plate. And plates could also be reproduced in books and
       | papers.
        
         | tejtm wrote:
         | "plates" at that scale are/were non portable, too much glass to
         | move. everyone would have to take themselves to the plates
        
         | Someone wrote:
         | On these plates, I would think stars effectively are point
         | light sources (https://en.wikipedia.org/wiki/Point_source#Visib
         | le_electroma...)
         | 
         | If so, there's not much more to see on these plates than
         | position and brightness (I assume these were black and white
         | plates, as color photography still was fairly experimental in
         | 1870)
         | 
         | Also they didn't make the map to look at individual stars (they
         | wouldn't use _"pictures of an enormous 3x2 degrees of the sky"_
         | for that), but to answer questions such as whether the
         | distribution of stars is uniform or whether stars move
         | relatively to each other in the sky. For both, you need
         | positions.
        
         | kergonath wrote:
         | I suppose it was easier to share books with tables of positions
         | than photographic plates. Easier to copy as well, and it does
         | not degrade quite as much with time.
        
       ___________________________________________________________________
       (page generated 2022-09-13 23:01 UTC)