Very simple radio telescope

[selden]

Here's an Addon which provides very simple 3D model of a radio telescope based on the telescopes used in the VLA.

http://www.lepp.cornell.edu/~seb/celestia/vla.html

[Verz Veraldi]

Hmm... that's pretty similar to the paper model you've created recently... Is it on Earth? There's no atmosphere...

Edit:
Errm.. I've tried it but..

2010-12-24_081132.jpg

It's flying... Or is it?

Edit once more (sorry):
There's more, I've got a screenshot here, showing the reflector, but....

2010-12-24_083658.jpg

It's still flying, but the reflector seems to tilt and the feet goes through the disk..

[Cham]

This is a very nice model, Selden. Thanks a lot for this addon . I may use it a bit in my astronomy classes, as a demonstration about how radiotelescopes are working.

Too bad the dish is rotating through its base, though (wrong intersection during the night phase).

Can you make a version without any motion ? Or a motion for which the dish never overlap its base ?

Also, a version with several radiotelescopes would be nice (array of radiotelescopes)...

Merry Christmas, by the way.

[selden]

Cham and Verz,

As stated in the readme, it seems to be floating because there's no DEM included to provide the actual ground level. The SSC file places it at the correct altitude which is quite a bit above the nominal surface provided by the sphere that Celestia uses to represent the Earth.

To eliminate the telescope's movement, you can edit its SSC file to delete the reflector's Modify section.

Here's vla01.ssc which takes care of both issues:

Code: Select all

# vla telescope model -- simplified version
# modified to place the telescope on the surface of Celestia's sphere
# and to have a fixed orientation.

# Copyright (c) 2010 s.ball

# location of VLA taken from
# http://www.vla.nrao.edu/genpub/overview/
# Location: Plains of San Agustin, west of Socorro, New Mexico.
# latitude = 34°04'43.497" north = 34.0787492
# longitude = 107°37'03.819" west = 107.6177275
# elevation = 2124 m (6970 ft)
# Size:
#    Each antenna: 25 m (82 ft) in diameter, 230 tons.

# the position of the telescope

SurfaceObject "vla-01" "Sol/Earth"
{
   Class "invisible"
   Radius   0.0125

    FixedPosition { Planetographic [ -107.6177  34.0787  0.011]}
   FixedRotation {}
}


# the telescope dish
"vla-01-reflector" "Sol/Earth/vla-01"
{
   Class "component"

   Mesh "vla-dish.cmod"
   Radius   0.013

   NormalizeMesh false
   MeshScale 0.000055

   OrbitFrame { BodyFixed { Center "Sol/Earth/vla-01"}}
   FixedPosition [ 0 0 0 ]

   BodyFrame { BodyFixed { Center "Sol/Earth/vla-01"}}
   FixedRotation {Inclination 45}
}

# the yoke carrying the dish

"vla-01-yoke" "Sol/Earth/vla-01"
{
   Class "component"

   Mesh "vla-yoke.cmod"
   Radius   0.0125

   NormalizeMesh false
   MeshScale 0.000055 # arbitrary paper size

   OrbitFrame { BodyFixed { Center "Sol/Earth/vla-01"}}
   FixedPosition [ 0 0 0 ]

   BodyFrame { BodyFixed { Center "Sol/Earth/vla-01"}}
   FixedRotation {}
}

# the pedestal supporting the yoke

"vla-01-base" "Sol/Earth"
{
   Class "component"

   Mesh "vla-base.cmod"
   Radius   0.0125

   NormalizeMesh false
   MeshScale 0.000055 # arbitrary paper size

   OrbitFrame { BodyFixed { Center "Sol/Earth/vla-01"}}
   FixedPosition [ 0 0  0 ]

   BodyFrame { BodyFixed { Center "Sol/Earth/vla-01"}}
   FixedRotation {}
}


Here's a URL for a nearby viewpoint with this ssc:

cel://Follow/Sol:Earth:vla-01/2010-12-2 ... rc=0&ver=3

The region is a featureless, brown, desert area. Since Celestia does not (yet?) cast shadows in this situation, it's essentially impossible for it to look like it's sitting on the Earth's surface.

[Cham]

Thanks Selden. It's working great !

Could you make a full array (with fixed dishes) ?

Also, I suggest that you add a bit more details inside the dish, especialy on the four beams so they look like metalic supports. Currently, they aren't at the same level of details as the base.

[selden]

Cham,

Feel free to make an expanded SSC. I don't expect to work on it for a few weeks. I'm currently working on a detailed model of one of the VLA telescopes which probably will keep me occupied for a month or two -- assuming I don't finish it over the holiday

[Verz Veraldi]

It works! The disk doesn't move anymore. It's still flying anyway.. Maybe I'll try to fix it sometimes..