**Previous message:**Anthony Ayiomamitis: "Re: ISS & STS"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]

> > > > If you are using the calculator within Windows, for example, you > will see a > > button for COS and also another for INV. If you want the arccos, ie. the > inverse of > > the cosine, enter your value, hit the INV box to check it off and then hit > COS. > > > Mathematically, arccos returns a value in radians = 180 degrees / PI() = > 57.29578 > The formula given assumes it is returned in degrees, which is the default in > Windows' Calc, but not in Excel and other programming systems - be careful > about that (also you should select menu View / Scientific to SEE the > functions - in Standard cos and arccos can be used by TYPING o and io) Bjoern, Thanks for pointing out that the calculator must be in "View/Scientific" mode as I forgot to mention that bit of trivia. I always have it in that mode and it is something that I inadvertently took for granted. > Anthony also asked 'at what altitude is the object '- this formula is for 0 > degrees, on (see-level) horizon. I am not the one who asked but the reply and content are what really matter .... :-) Anthony. > To find the ground range for another value, use the same formula for another > Earth radius, then subtract the distance corresponding to the elevation you > want (a). > With R=6371 km and a in degrees: > > DIST = R * {arccos[cos(a)*R/(R+HEIGHT)] / 57.29578} - a * R / 57.29578 > > assuming your calculator works completely in degrees. If using radians, use > DIST = R * arccos[cos(a / 57.29578)*R/(R+HEIGHT)] - a * R / 57.29578 > > With HEIGHT = 200 km, this gives for > a=0 DIST=1576 > a=5 DIST =1113 > a=10 DIST = 810 ... > a=85 DIST = 17 > > ----------------------------------------------------------------- > 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 ----------------------------------------------------------------- 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

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: Tue May 01 2001 - 03:18:43 PDT
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