# Homework Help: Solid Angle

1. Mar 5, 2006

### stunner5000pt

This isnt so much an astronomy question as one would think
A perfectly black satellite is in orbit around the earth at a height of 2000 km
What solid angle does the earth subtend when viewed from teh satellite?

$$\cos \theta = \frac{6370km}{8370km}$$
WEll if we look at hte diagram the angle theta is 40.4 degrees or 0.705 radians

we want the solid angle which is defined as
$$\Omega = \int_{0}^{2 \pi} \int_{0}^{0.705} \sin \theta' d \theta' d \phi$$

is this fine?

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2. Mar 6, 2006

### Meir Achuz

Isn't that sin theta.? Remember Sohcahtoa.