It is my understanding that the deployment of the MAST tether (31126 / 07012K) was expected to have been completed by now, and efforts to confirm this are underway. Visual observations likely would be of value in determining the degree of success of the deployment, and the tether's initial orientation. MAST's orbit is well placed for evening observation at latitudes north of about 40 N. Heavens-Above has elements. It is expected to appear as a luminous line of a few arc minutes length, visible using binoculars and telescopes. The MAST blog encourages observations, with special interest in images: "We'd welcome receiving copies of any photographs or video captures you might make. Notations on camera orientation and observation time would be especially helpful in aiding with processing of tether dynamics data." http://www.tethers.com/MAST_Blog.html If you obtain images or video, I suggest contacting MAST's owner, Tethers Unlimited, Inc. (TUI) at mast@tethers.com The tether is 1 km in length. Its apparent length will depend on its orientation with the respect to the observer, altitude above the Earth, and elevation above the observer's horizon. The orbit is approximately 644 x 779 km, and observable passes currently occur near apogee, so the following estimates are based on 779 km. If the tether is oriented within the plane normal to the radius between it and the observer, then it will appear longest when directly overhead (90 deg elevation), with an apparent length of about 0.074 deg = 4.41 arc min. At 45 deg elevation its apparent length would be 0.056 deg = 3.33 arc min. Within a few weeks, the tether is expected to assume a gravity gradient orientation, like that of Tips, in which case its maximum apparent length will occurs near 42 deg elevation above the horizon, with an apparent length of about 0.035 deg = 2.08 arc min. The apparent length would not be very sensitive to elevation, remaining within 15 percent of maximum over the range between about 23 deg and 59 deg elevation. Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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