Sea visible from London??

[davew]

Hi, I'm quite new to Celestia but have been having a lot of fun looking for bigger and bigger Earth textures

I recently discovered the "goto surface" command, and tried it with my home city of London. However, at roughly 300m off the ground (about the height of the Empire State Building, I'm told) I can see both the curvature of the earth and the sea. Surely something not right there?



Regards
Dave

[Guest]

OK - I tried this with a higher-resolution texture

http://exp.arc.nasa.gov/downloads/celestia/extras/)
(Blue Marble VT, DDS format)

..and as you can see it's pretty much the same.



I conceed in this shot the viewpoint is a bit higher (500m) but I didn't seem to be able to get the camera any lower this time round. Either way, the curvature of the earth is quite pronounced and I can see right out past the humber estuary clear to Flamborough and Bridlington in East Yorkshire, a distance of approx 295 kilometers!

Surely this can't be right? the top of the Petronas Towers in Kuala Lumpur is at about 500m....

Regards
Dave

[selden]

Dave,

What version of Celestia are you using?

I get a similar curvature of the surface at an altitude of about 20 KM, not 500 M.

Is there any chance the radius for the Earth has been damaged in your solarsys.ssc? It should be

Radius 6378.140 # equatorial

[Matt McIrvin]

Could this have to do with the Earth's oblateness? Ever since oblate atmospheres got fixed, it's been possible to give Earth a correct nonzero oblateness in solarsys.ssc (though it might still be turned off by default). But altitude calculations aren't right for oblate planets yet, unless you're at the equator, which London definitely is not!...

[granthutchison]

Oblateness is still commented out for the Earth (Chris tells me it was producing VT problems), so that shouldn't be a problem unless the ssc has been edited or damaged.

Dave, I can't reproduce your problem - when I'm 500m from London I get an appropriately limited view of the surrounding territory.
As well as telling us what version you're using, can you let us know the exact key sequence you use to get to the position in your screenshot, and if you have any Locations add-ons installed (like Fridger's big locations file).

Grant

[Guest]

Aha - the oblateness might indeed be the key. I uncommented it, can't recall why. I have put it back the way it should be, and all seems well with the horizon again. The view distance does seem to be improved too.

Thanks!
Dave