Hi 2010/3/3 [email protected] <[email protected]>
> I think that no comparison can be made between different programs results > without knowing the value of DeltatT that has been used. > I again think that DeltaT is not needed if we calculate apparent places and use UT. Most accurate link capable for that (what I know) is at http://ssd.jpl.nasa.gov/horizons.cgi#results If refraction is not calculated, the link gives azimuth=200.7239 and altitude = 39.1824 (39.2031 if refraction is included) Regards Aimo > Ephemeris tables usually declare the value of DeltaT that was used. > It is also worthy to note that for gnomonic applications all these results > are more than correct :-) > Regards. > Gian > > > > ----Messaggio originale---- > Da: [email protected] > Data: 03/03/2010 20.51 > A: "John Goodman"<[email protected]> > Cc: "Sundial List"<[email protected]> > Ogg: Re: Solar position calculator > > > Hi > I got following results from the link > http://www.roman-britain.org/astronomy/astro.htm# > which I believe is trustworthy > > azimuth=200.7233 (20.7233 if south is the zeropoint) > altitude= 39.1827 > > I also tested the results with my own semi-accurate PcAllakka > with following results > azimuth=200.715 and altitude=39.188 > Anyone interested can load the program from > http://pc-calculator.110mb.com/allakka/ > > or perhaps some of you is curious enough to visit my solar tracking sundial > pages at > http://pc-calculator.110mb.com/tracker/solartracker.html > > Greetings > Aimo Niemi > > > 2010/3/3 John Goodman <[email protected]> > >> If anyone needs to make precise solar position calculations, the following >> software may be useful. There are a few caveats. The software is not a >> stand-alone application, it's a software library. The software library needs >> to be used from the command line and it runs using the Python programming >> language. >> >> >> I'm a Mac user and this is one of those rare occasions when an arcane set >> of requirements actually favors the Mac. While Macintosh users tend to be >> allergic to the command line, it has existed in the OS for the past 10 >> years. Python is there too, lurking under the surface. >> >> I don't know enough about the PC, but clearly the command line is there >> and Python is available too. ( http://www.python.org/download/windows/ ) >> >> With all that preface, here's what the code can do. Once the necessary >> files are installed, you can type the following commands and see the >> following results: >> >> >>> import datetime, solar >> >>> d = datetime.datetime(2010, 3, 3, 18, 0, 0) >> >>> lat = 42.0 >> >>> long = -71 >> >>> solar.GetAltitude(lat, long, d) >> 39.203509044804704 >> >>> solar.GetAzimuth(lat, long, d) >> -20.717667802423591 >> >>> >> >> Someone with an ephemeris can check these results. The format for datetime >> is "yyyy, mm, dd, hh, mm, ss", optionally followed by a number of >> microseconds. The time value entered is for UTC. >> >> There are other functions for calculations that I haven't explored. You >> can read more about the software tools at http://pysolar.org/ Example >> uses are shown at http://wiki.github.com/pingswept/pysolar/examples The >> software itself is at http://github.com/pingswept/pysolar/downloads >> >> All of this software is the work of Brandon Stafford, who has generously >> offered his code free of charge to anyone who may find it useful. I have >> little experience with this software but, as much as I can, I'll be happy to >> help anyone trying to use it. >> >> If there are any questions, I can pass them on to Brandon. I hope this is >> helpful to some. >> >> --------------------------------------------------- >> https://lists.uni-koeln.de/mailman/listinfo/sundial >> >> > > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > >
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