Given that the masses on STW can answer anything....

OK....I have a theoretical light positioned shining vertically downwards at a height of 30 metres and the beam angle creates a spot diameter of 6.3 metres.

I need to create an elliptical spot, maintaining 6.3m along the shortest axis and a the longer axis needs to be 7.9m. The distance from the light to the centre of the ellipse needs to remain at 30m.

What's the formula for working out the angle at which the light should be tilted to create this ellipse?

I'm knackered and now my head hurts...

Enlighten me?