The following table gives the theoretical apparent angular length of the TiPS tether based on 1) a tether length of 4.0 km. 2) circular orbit of height 550 nautical miles (1019 km) 3) tether pointing vertically down Elev. Length Elev. Length Elev. Length deg arcmin deg arcmin deg arcmin 0.0 3.16 30.0 5.93 60.0 5.15 5.0 3.65 35.0 6.15 65.0 4.52 10.0 4.17 40.0 6.24 70.0 3.77 15.0 4.68 45.0 6.19 75.0 2.92 20.0 5.17 50.0 5.99 80.0 1.99 25.0 5.59 55.0 5.64 85.0 1.01 90.0 0.00 The maximum apparent length is 6'.25 (0.104 deg) at an elevation of 41 degrees. Note that the apparent length near the horizon is still substantial despite the greatly increased distance. Being site independent, one only need note the predicted elevation to derive the length. Paul Maley noted a length of 0.12 deg at 31 deg elevation, close to the prediction above of 0.10 deg. However Paul's maximum length of 0.17 deg is much longer than the maximum predicted (0.104 deg). I don't believe I have made any error in the calculations (but someone may like to check), which would imply one or more of the initial assumptions are in error. Certainly, if the tether were perpendicular to the line of sight when overhead, it would subtend 0.42 deg, so a moderate tilt could happily accomodate Paul's observation. Cheers, Rob McNaught aaocbn2.aao.gov.au