10-15-2020, 03:04 PM
An extract from Calculate OSCAR Orbits, … with your HP-25 calculator, 73 amateur radio, NOV 1977, #206, pgs. 80-81
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Last year I developed an interest in OSCAR activity after having read a back issue of 73 that was entirely devoted to this subject. When I sat down to work out the orbital times to look for 06 and 07 in my area, I decided very quickly t here had to be a better way. The calculation of orbit #5, for example, on any given day can be a time consuming effort at best, and, if you want the most likely times for communication via this mode on a daily basis throughout the month, these calculations could be a down right nuisance unless you have access to a complete list of tables for this purpose.
Since my HP-25 was sitting idle and I was still trying to justify its purchase price, I decided that it was about time it should start doing more than calculating debits from my savings account.
This program is not very complicated in the sense that it doesn't work out any heavy math problems, but it does do the job of working out the orbits of either 06 or 07 between the times listed each month in 73. The program will update the orbital number, the equatorial crossing and time of crossing for each successive pass from the first pass listed for each day. If you wish, subtracting the number of hours you are from GMT on the first entry will result in a local time readout for the equatorial crossing.
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BEST!
SlideRule
"
Last year I developed an interest in OSCAR activity after having read a back issue of 73 that was entirely devoted to this subject. When I sat down to work out the orbital times to look for 06 and 07 in my area, I decided very quickly t here had to be a better way. The calculation of orbit #5, for example, on any given day can be a time consuming effort at best, and, if you want the most likely times for communication via this mode on a daily basis throughout the month, these calculations could be a down right nuisance unless you have access to a complete list of tables for this purpose.
Since my HP-25 was sitting idle and I was still trying to justify its purchase price, I decided that it was about time it should start doing more than calculating debits from my savings account.
This program is not very complicated in the sense that it doesn't work out any heavy math problems, but it does do the job of working out the orbits of either 06 or 07 between the times listed each month in 73. The program will update the orbital number, the equatorial crossing and time of crossing for each successive pass from the first pass listed for each day. If you wish, subtracting the number of hours you are from GMT on the first entry will result in a local time readout for the equatorial crossing.
"
BEST!
SlideRule