Re: Angular diameter discrepamcy in Calsky

From: Thierry Legault (legault@club-internet.fr)
Date: Tue Apr 19 2011 - 19:03:35 UTC

  • Next message: Ted Molczan: "RE: Angular diameter discrepamcy in Calsky"

    yes Guiseppe, the angular diameter is wrong when you click on a dot
    on the centerline, but the size given in the main passage and transit page
    is good.
    I doubt that with orbital data deduced from amateur observations, the
    accuracy would be sufficient for a transit! If you got a dark dot on your
    images, you'll have to check that the trajectory and speed of the object
    is consistent with Calsky calculations. So many objects are able to
    make moving dark dots: birds, bats, insects etc.
    
    regards
    
    Thierry Legault
    www.astrophoto.fr
    
    
    At 20:34 19/04/2011, you wrote:
    
    >9h32m48.60s
    >CalSky-Details. 22.Apr.2011 9h32m48.60s: 
    >Lacrosse 3 (25017 1997-064-A) in front of Sun. 
    >Transit-Duration: 1.47s, path width: 15.58km. 
    >Diameter of Lacrosse 3 (25017 1997-064-A): 42.33"
    >
    >
    >
    >
    >
    >The above is obtained by clicking on one spot of 
    >"Centerline". It says angular diameter 42.33"
    >
    >Below is the message from alert manager.
    >
    >Although my location is a couple of Kms far from 
    >the centerline, PA, transit duration and 
    >separation obviously change, but angular 
    >diameter should not (at least not 12fold) . Any hints?
    >
    >       9h32m48.46s Lacrosse 3
    >       (25017 1997-064-A) Crosses the disk of 
    > Sun. Separation=0.246  Position Angle=330.6.  Transit duration=0.55s
    >       Angular diameter=3.5"  cylindrical, 18.0m x 4.5m
    >       Satellite at Azimuth=106.5 ESE  Altitude= 33.0  Distance=1100.1 km
    >       In a clock-face concept, the satellite will seem to move toward  8:30
    >       Angular Velocity=21.8'/s
    >
    >
    >
    >
    >
    >Giuseppe
    >
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    Thierry Legault
    www.astrophoto.fr
    
    
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