Re: forwarded moon transit movie

From: Ed Cannon (ecannon@mail.utexas.edu)
Date: Sat Jan 27 2001 - 18:11:30 PST

  • Next message: Bjoern Gimle: "Re: Iridium 51 orbit adjustment"

    Maybe a large bird at a very long range could qualify as 
    the object in the lunar-transit movie.  SeeSatters wrote:
    
    >> ... at 60 degrees, 3.33 km.  I think these altitudes 
    >>are too high for a small bird.  What about a larger bird?
    >
    >I've seen very small birds ... at cloud base around 1 to 
    >1.5 km .... Whether the small birds would do it at night 
    >is another question ....  Perhaps during migration?
    
    FWIW, migrating bar-headed geese fly over the Himalayas 
    twice per year, and it's claimed they've been seen flying
    over Mount Everest and other high peaks:
    
     http://magazine.audubon.org/birds/birds0011.html
    
    At night?  Here's a quote from the above article:
    
    ] One evening during a Himalayan expedition, he was 
    ] startled by the honking of night-flying bar-headed geese
    ] passing directly over Mount Makalu's 27,824-foot summit.
    
    Bar-headed geese are about 75 cm (30 inches) long or tall.
    Probably their wingspan would be about twice that (?).  The 
    other day I wrote:
    
    > At 1/1000 lunar distance (about 385 km), it's 7 meters in 
    > diameter (satellite size).
    
    So, at 1/10000 l.d. (about 38.5 km), "it" would be .7 meters 
    in diameter (goose size).  Based on information I received 
    in a private message, at a range of about 40 km, 0.5 degree 
    in 24 seconds would be roughly 400 meters, or 1000 m/minute, 
    or 60 km/hour.  (Hope my math is correct!) Bar-headed geese 
    fly at a "cruising speed" of up to 80 km/hour.  
    
    So, if I've done the math correctly, it seems that a large 
    bird at a surprising range could a candidate for the movie.  
    By the way, the Audobon article says, "The highest-flying 
    bird ever recorded was a Ruppell's griffon, a vulture with a 
    wingspan of about 10 feet; on November 29, 1975, [one] was 
    sucked into a jet engine 37,900 feet..." (about 11500 meters).
    
    I haven't checked the reports in the above article for urban
    (or rural?) legend status....
    
    Lovely weather we are NOT having....
    
    Ed Cannon - ecannon@mail.utexas.edu - Austin, Texas, USA
    
    -----------------------------------------------------------------
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org
    http://www2.satellite.eu.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Sat Jan 27 2001 - 18:13:10 PST