[bkm2304 (Richard Brown)]

OK,

If we do a bit of trig the following falls out of the sky!

Plato makes a nice comparator on the moon. The image is fairly well focussed so we can deduce that Plato at 109Km diameter and the moon at 397,900 Km during mid - eclipse gives Plato an angle of .94 Arc minutes. Comparing the shape when it is actually crossing the moon is a better estimate than the flare it takes on when against the darker sky. I estimated the shape "solid" at about 0.8 diameters of Plato giving an angular size of approx. 0.75 Arc mins.



Applying trig to these values we get the following table (Note this is DISTANCE from observer NOT Height ABOVE the surface):

Object Size Distance
.1m (bat, Owl) 450m

1m (Flying Black Swan) 4.5km

10m (Light Aircraft) 45km

50m (Commercial Airliner) 228km

100m (ISS or similar) 456km

Given the moon was at 45 degrees altitude mid eclipse (ish) then we need to adjust for this. I will leave it to the true geometers to do the correct adjustment from the surface of the earth above the object at different distances from the viewer.

But adjusting for the altitude angle using more trig we get:

Object Size Corrected Distance(Height)

.1m (Bat, owl) 320m

1m (Flying Black Swan) 3.2km

10m (Light Aircraft) 32km

50m (Commercial Airliner) 161km

100m (ISS or similar) 318km

Bats and swans don't fly at 320 and 3,200m respectively. Cessna 4 seaters don't ever get to triple the height of Mt Everest. Airbuses certainly don't go to lower Earth Orbit. So, on the size of it, that leaves a rather largish satellite. It is NOT the ISS as it was set, nor was it the Hubble which is too small anyway. It may be a satellite with panels out but I have no idea which one it is.

Based on these calcs a satellite in low earth orbit fits the bill.

Cheers,

Euclid ....er sorry, .... Richard.