What's a Two Line Element Set (TLE)?
A two line element set (TLE) is a group of numbers provided in two lines and separated by spaces, that specify the orbital parameters (elements) for a satellite, spent booster rocket, or other man-made satellites.
A Typical TLE, and what the numbers are:
ISS (ZARYA) 1 25544U 98067A 02166.25000000 .00022749 00000-0 30765-3 0 5637 2 25544 51.6332 62.6174 0006804 238.6710 31.2451 15.57611327203721
NAME 1 [IDXXXU] [Int Desig] [Epoch] [FTD MM] [STD MM] [drag] [Eph T] [Ele #] 2 [IDXXXX] [Inc] [RA AN] [Ecc] [AOP] [MA] [Revs]+[ON]
Note: Not all these numbers are needed for programming your Autostar manually. Downloadable TLE's can be imported into the Autostar using the Meade #505 cable or equivalent, and the Autostar update software.
ISS (Zarya) - International Space Station, (Zarya Module)
1 25544U 98067A 02166.25000000 .00022749 00000-0 30765-3 0 5637
1 [IDXXXU] [Int Desig] [Epoch] [FTD MM] [STD MM] [drag] [Eph T] [Ele #]
ID = Satellite Number - 25544U (U=unclassified)
Int Desig = International Designation (date lauched, launch number of year, section) - 98067A
Epoch = Year (last two digits) , day of year, and fractional day - 2002, day 166.25000000
FTD MM= First Time Derivative of Mean Motion - .00022749
STD MM= Second Time Derivative of Mean Motion - 00000-0
drag = BSTAR drag term (decimal assumed) - 30765-3
Eph T = Ephemeris Type - 0
Ele # = Element Number - 5637
2 25544 51.6332 62.6174 0006804 238.6710 31.2451 15.57611327203721
2 [IDXXXX] [Inc] [RA AN] [Ecc] [AOP] [MA] [Revs]+[ON]
ID = Satellite Number - 25544
Inc = Inclination (degrees) - 51.6332
RA AN = Right Ascension of Ascending Node (degrees) - 62.6174
Ecc = Eccentricity (decimal assumed) - .0006804
AOP = Argument of Perigree (degrees) - 238.6710
MA = Mean Anomaly (degrees) - 31.2451
Revs = Revolutions per day - 15.57611327
ON = Orbit Number at Epoch - 20372(.)1
That's "Aquisition of Signal", or when and where the Autostar will first "see" the satellite above the horizon. Newer firmware (from 25.Ea forward) allows you to edit the AOS horizon (if you have trees or other obstructions in the way) or older firmware with Dick Seymour's Autostar patches.
|| Back to Contents || Wedge adapter || Focuser || Azimuth adjuster || Weight Set || Dovetail ||
|| Compass || Polar || Pinouts || Tours/Ephemerides || LED Markers || Balance || Focuser Bearings ||