Re: Geo local altitude

From: Bjorn Gimle \(TietoEnator\) (bjorn.gimle@tietotech.se)
Date: Tue Nov 27 2001 - 05:04:54 EST

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    Compute the position of the geostationary in your equatorial plane:
    X=(35790+6370)*COS(dLong)-6370*COS(Lat)
    Y=(35790+6370)*SIN(dLong)
    Z=-6370*SIN(Lat)
    
    And the distance to the geostationary:
    D=SQRT(X*X+Y*Y+Z*Z)
    
    Then the altitude of the geostationary is
    Alt = ASIN((X*COS(Lat)+Z*SIN(Lat))/D)
    
    With dLong = 101-80.14 = 20.86
    and Lat = 42.07
    I get Alt = 36.99 degrees
    
    You will have Alt>10 for 64.6 degrees, i.e. Long = [-15.52,-144.76]
    And Alt>0 for Long = [-1.89,-158.39]
    
    > Does anyone have a formula (other than star charting software) for
    > calculating a geosat's apparent altitude given its final parking
    longitude?
    >
    > For instance tonight's DirecTV launch is destined for 101 degrees West.
    
    Excel spreadsheet sent to Bill.
    
    -- bjorn.gimle@tietotech.se (office)                         --
    -- b_gimle@algonet.se (home)  http://www.algonet.se/~b_gimle --
    -- COSPAR 5919, MALMA,    59.2576 N, 18.6172 E, 23 m         --
    -- COSPAR 5918, HAMMARBY, 59.2985 N, 18.1045 E, 44 m         --
    
    
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