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Airliner

PostPosted: Thu Mar 31, 2011 5:08 am
by Aviator
Found what I think is A321 on Google Earth. It is not very often you get to see a cruising airliner from above... from waaaaay above :shock:
airliner and its ghost.jpg
airliner and its ghost.jpg (223.3 KiB) Viewed 2321 times

Re: Airliner

PostPosted: Wed May 11, 2011 6:41 am
by disco stu
Thats pretty cool actually. Its got its angel with it :D :roll: Must be a reflection in the sensor or something I imagine

Re: Airliner

PostPosted: Thu May 19, 2011 4:27 am
by Aviator
disco stu wrote:Thats pretty cool actually. Its got its angel with it :D :roll: Must be a reflection in the sensor or something I imagine


I was wondering myself what would that be. It doesn't quite line up with the ground based shadows... but then again, the plane is probably cruising 10 kilometres above the ground.
A reflection in the sensor is an interesting thought... but why would only the flying plane make a reflection?

Re: Airliner

PostPosted: Tue Jun 07, 2011 1:21 am
by disco stu
I'm running very late here, sorry.

Thats a good point about only the plane making a reflection and nothing else. I did notice that the plane seems to be in black and white, and the "angel/reflection" seems to be in colour. Leads me to think that maybe there are 2 sensors sitting fairly seperate that are aligned for ground level and the plane being somewhere above it means that the 2 images don't line up???? Maybe????

Re: Airliner

PostPosted: Tue Jun 07, 2011 5:16 am
by Aviator
Let's try some math. Those images are little bit more than a wing span apart (34.1m). Lets estimate that the plane and its shadow are 36.0m apart. Lets assume that the plane is cruising at 10 km and the satellite is at 200km. 36:10 000=X:200 000 X=720 This is a very rough estimate, but I think it gives us an idea. That means that two sensors would have to be 720 meters apart in order to have the surface in focus, and have the plane and its shadow 36 meters apart.

I do remember seeing grey shadows of contrails from the ground. There would have to be a layer of something at high altitude (a haze of some sort - most likely pollution) Would it be possible that from space those shadows would appear as blueish?
This is a closeup of it

airliner A321-200 and its ghost2.jpg
airliner A321-200 and its ghost2.jpg (148.02 KiB) Viewed 2220 times

Re: Airliner

PostPosted: Thu Jun 09, 2011 5:28 am
by disco stu
I asked around at work, and one guy who is well versed on things was talking about how if you watch your shadow when in a plane from take off, it will be a shadow that gets smaller and smaller, then it will turn into a white/light dot that will get bigger and bigger as you go up in altitude. He can't remember what its called, but its from the light bending around the object, in that case an aircraft. Not sure if its refraction or what. I assume it is then seen on cloud or certain layer depending on atmospheric conditions, as he said he has seen it happen in helicopters at only a few thousand feet.

In this case it would seem, if this is the explanation, that the sun is on a fairly close angle to the sensor hence the "refracted" image is fairly close.

Best I can come up with, but thought you may like to look into that one a bit more