Location: '34 South' Young Hilltops LGA, Australia
Posts: 1,481
Just tried to observe the 20:02-20:06 pass from west outskirts of Canberra. Supposed to be mag 3.8. I couldn't see anything naked eye. Try again at 2130.
I'm just keeping tabs on the Heavens Above site, nothing there on predictions just the height and location but I guess when that starts dropping low it will be close to re entry time. http://www.heavens-above.com/GroundTrack.aspx
Just tried to observe the 20:02-20:06 pass from west outskirts of Canberra. Supposed to be mag 3.8. I couldn't see anything naked eye. Try again at 2130.
Joe
Likewise I saw nothing in the time around 8pm when it was predicted to pass near Melbourne. (Cloudy with some clear patches.)
Location: '34 South' Young Hilltops LGA, Australia
Posts: 1,481
The altitude has been around 180-190km for the past day and decaying very slowly. I think it needs to decay to around 150-160km before it really starts the rapid dive.
I guess the big question is how much notice will we get before re entry actually starts. I'm sure there are a few of us that would like to be outside looking up in case we are lucky enough to catch it burning up on one of the Aust passes.
Location: '34 South' Young Hilltops LGA, Australia
Posts: 1,481
Rick,
Chances of getting the exact time of burn up is very unlikely due to the uncertainties in atmospheric density and dynamics.
Given that each pass is only 5-10 minutes, and only a few are visible each day, I'm covering as many as I can.
Even when I add in a 5 minute each way drive to a semi dark sky lookout on the edge of the city, each attempt is only taking 20 minutes. Given the near full Moon a fully dark sky is unnecessary.
Starting to drop rapidly now. I went outside just before as it passed over but couldn't see it. Not sure if it's naked eye visible - especially with the Moon helping to wash everything out?
Is the up and down yo-yo-ing an effect of the atmosphere? Like a stone skipping on the water before it finally sinks into the pond?
Markus
More like an elliptical orbit I would think.
Our atmosphere only extends to 90Km in height, according to the attached diagram. The heavens above website says that re-entry will not occur until Tiangong reaches 100Km in height.
I just watched the last orbit cycle and its highest was 170Km midway between Cape Town and Perth, and its lowest was 153Km in the Nth Pacific at 20°N.
Seems to be losing 100m every 25 seconds now... not long. Pity, looks like it's just gonna make it past northern China. Nothing wrong with recycling eh :p
EDIT.. approaching the Western Chinese border, gaining 100m every 10 secs. How convenient...
Last edited by AndyG; 02-04-2018 at 09:36 AM.
Reason: adjusting my tinfoil hat.
