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samtx / passpredict

Predict upcoming satellite overpasses over a point on Earth.
MIT License
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Compute satellite visibility #4

Closed samtx closed 4 years ago

samtx commented 4 years ago

Compute the visibility of a satellite during an overpass event.

samtx commented 4 years ago

To compute apparent magnitude, refer to this equation from http://www.satobs.org/seesat/Apr-2001/0313.html:

Mag = Std. Mag - 15 + 5LOG(Range) - 2.5LOG(SIN(B) + (pi-B)*COS(B))

where Range is in km, and B is in radians and measures the angle from the sun to the satellite to the observer. At full phase, B is 0; at new phase, B is pi (i.e. satellite transiting the sun).

I want to emphasize that this is the correct equation for a spherical satellite with a perfectly Lambertian surface. Of course, few satellites are spherical, and none have perfectly Lambertian surfaces. Still, it is a good approximation when you don't know the orientation of a satellite.

And from this stackexchange post: https://astronomy.stackexchange.com/questions/28744/calculating-the-apparent-magnitude-of-a-satellite

samtx commented 4 years ago

Created initial implementation of brightness magnitude in commit 90cee6c596dba7ae052f2d11e9b0b52052763426