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Accurate position of the Sun
Greetings all,
I am looking for the most accurate way to determine the position of the sun with respect to an orbiting satellite. I've searched on the web and received conflicting information from our astronomy department on whether the JPL solar ephemeris data is suitable. The problem with using HORIZON is that I need the solar position relative to an orbiting satellite and in reading the documentation, it isn't particularly obvious how to do this. Moreover, I need to be able to calculate the position accurately until 2005. Any ideas or advice would be greatly appreciated! Cheers, Graham |
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Accurate position of the Sun
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Accurate position of the Sun
"Graham" wrote in message
om... Greetings all, I am looking for the most accurate way to determine the position of the sun with respect to an orbiting satellite. Orbiting what? Presumably the Earth... I've searched on the web and received conflicting information from our astronomy department on whether the JPL solar ephemeris data is suitable. The problem with using HORIZON is that I need the solar position relative to an orbiting satellite and in reading the documentation, it isn't particularly obvious how to do this. Moreover, I need to be able to calculate the position accurately until 2005. Any ideas or advice would be greatly appreciated! Whoever owns the satellite should be able to provide accurate ephemerides for it, presumably in an Earth-centered frame of reference. The Sun's position in an Earth-centered frame can be had from HORIZONS. MICA 1.5 has been released. It covers the time period to 2005: http://aa.usno.navy.mil/software/mica/micainfo.html The rest is just vector addition. |
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Accurate position of the Sun
On Mon, 8 Mar 2004 13:34:33 -0500, "Greg Neill"
wrote: "Graham" wrote in message . com... Greetings all, I am looking for the most accurate way to determine the position of the sun with respect to an orbiting satellite. Orbiting what? Presumably the Earth... I've searched on the web and received conflicting information from our astronomy department on whether the JPL solar ephemeris data is suitable. The problem with using HORIZON is that I need the solar position relative to an orbiting satellite and in reading the documentation, it isn't particularly obvious how to do this. Moreover, I need to be able to calculate the position accurately until 2005. Any ideas or advice would be greatly appreciated! Whoever owns the satellite should be able to provide accurate ephemerides for it, presumably in an Earth-centered frame of reference. But bear in mind that the satellite may have orbit under conditions that make long term prediction of it's position impossible, or may be subject to orbital adjustments. You may not be able to get a reliable ephemeris for the satellite as far out as 2005. Al Moore |
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Accurate position of the Sun
"Alan Moore" wrote in message
... But bear in mind that the satellite may have orbit under conditions that make long term prediction of it's position impossible, or may be subject to orbital adjustments. You may not be able to get a reliable ephemeris for the satellite as far out as 2005. True enough. And many satellites do station keeping and adjust their orbits dynamically to maintain nominal orbit for their mission. From now to 2005 is now less than a year. Surely the owners of a satellite would have a handle on its position for its working life? |
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