rickc@agora.UUCP (Rick Coates) (03/03/89)
In article <6528@ecsvax.UUCP>, jdmce@ecsvax.UUCP (Duncan McEwen) writes: > > > Does anyone have experience with Rick Coates' planet.exe. It was Thanks. Should I post moon.exe and sun.exe? > posted recently on comp.binaries. I am delighted with the program > but can't get the local time for rising and setting to work right. > The numbers look ok when I default to the west coast, but when I > input my own east coast LONG and LATI, the rising times don't make > sense. > > Supposedly, it is possible to insert an environment variable TZ= > ones local time zone. When I try TZ=EST it still doesn't work. This should be Unix standard... TZ=EST4EDT (I think - I've never had to do it for the East Coast) The middle digit is what is important - it is the number of hours west of GMT. (I've actually never tested it for the east coast - let me know if it doesn't work). You can also use the command line argument to set latitude and longitude. > Any suggestions. > > I would also appreciate it if an astronomer would help me distinguish > between geo and topocentric equatorial positions. (I'm not an astronomer, but...) Not much difference at all for planets - but there will be for the moon program. Geocentric is for an observer at the center of the earth; topocentric is for where you are on the surface of the earth. > > I'm also curious to know what an hour-angle is. Astronomy has all sorts of ways of describing positions. Hour-angle is the angular distance from 'straight up' where and when you are. An hour angle of 0 is straight up. > > One last question. Would someone care to explain how azinmuth is defined. > Azimuth is the angular distance (usually, and in the case of my planet program) from due north clockwise. Elevation is how high in the sky the object is. > Thanks in advance. Please forgive any dumb mistakes I might have made in my explantion. Rick Coates tektronix!reed!percival!agora!rickc
jdmce@ecsvax.UUCP (Duncan McEwen) (03/07/89)
Rick, Thanks for planet.exe. The only other question I have that might be of general interest is this: I notice that for dates before ca. 1980 and after 2030 the program gives planet positions but the rise and set information is no longer available. Are the planet positions still accurate? Would it be easy to modify the program to give rise/set data for a broader range of dates? I sure would appreciate it if you would post moon.exe and sun.exe and I bet others subscribers would too.
rickc@agora.UUCP (Rick Coates) (03/13/89)
In article <6617@ecsvax.UUCP>, jdmce@ecsvax.UUCP (Duncan McEwen) writes: > Rick, > > Thanks for planet.exe. The only other question I have that might be > of general interest is this: I notice that for dates before ca. 1980 > and after 2030 the program gives planet positions but the rise and set > information is no longer available. Are the planet positions still > accurate? Would it be easy to modify the program to give rise/set > data for a broader range of dates? I never tried this, but I bet the answer is: MSDOS has problems with dates before 1980 (I know) and I bet after 2030. I use the Unix like date routines provided by Microsoft C for this. The answer is: recompile on a real system (even then, it would have problems before 1970 and after 1970+2^32 seconds, and, of course, I haven't supplied source). The other option is to re-write localtime(). > > I sure would appreciate it if you would post moon.exe and sun.exe and > I bet others subscribers would too. I doubt I will, at this point, since the total comments have been about two. I am also considering rolling the whole thing into one (planets, sun, moon) program. Rick Coates ...!tektronix!reed!percival!agora!rickc 0133 SW Orchid Ct. Portland, Oregon 97219