How does one determine the age of the keps in a computer?
73 Bob W7LRD
On 2/19/2011 8:09 PM, Bob- W7LRD wrote:
How does one determine the age of the keps in a computer?
I guess that depends on what you are trying to look with. I use Nova for windows and it will tell how old the keps are for the selected satellite by selecting AutoTracking > Summary. That resulted in:
Satellite name : OSCAR 10 Catalog number : 14129 Keps age : 1174d,03hr Next AOS : Location : Glendora, CA Latitude : 34° 07' 00" N Longitude : 117° 51' 00" W Algorigthm : G3RUH AutoTracking : Disabled
The 3rd line shows the age of the keps. Yes, those really are 3 1/2 years old...
If you look at a TLE file, the epoch time is the 3rd element in a 2 digit year followed by the 3 digits before the decimal and a bunch after the decimal point. So in the TLE below, the epoch time was 32.75507474 days into 2006. AO-07 1 07530U 74089B 06032.75507474 -.00000028 00000-0 10000-3 0 05556 2 07530 101.5919 078.9684 0012116 149.1255 211.0532 12.53571784428419
Here is a web site that explains it. http://www.satobs.org/element.html
Open the keps file and look at the first line of data for a given satellite. The 3rd number group (the first one with a decimal point in it) is the "epoch time" - the date & time when the orbital parameters were calculated. The first 2 digits are the year, the next 3 are the Julian date (day # out of 365), and the decimal portion is the time, expressed as a fraction of a day.
Looking at the current 2-line set on the AMSAT website, all of the satellites have an epoch time of either 11047.xxxxx or 11048.xxxxx, meaning they were calculated on day 47 or 48 of this year.
George, KA3HSW
----- Original Message ----- From: "Bob- W7LRD" w7lrd@comcast.net To: amsat-bb@amsat.org Sent: Saturday, February 19, 2011 10:09 PM Subject: [amsat-bb] keps age
How does one determine the age of the keps in a computer?
73 Bob W7LRD
participants (3)
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Bob- W7LRD -
George Henry -
Jim Walls