Why is the moon distorted at low angles

We had the pleasure of watching the moon rise tonight, something I have to admit I have never seen before. I wondered why is it distorted at low angles (just above the horizon).

It was kind of an oval shape and the colour was orangy/yellow.

I hypothesise that because of the low angle the light is passing through more of the atmosphere and that distorts the shape.

Thanks!

Your hypothesis is correct, but their are other factors in play, such at atmospheric pollution (orange colour) and a rather mysterious optical illusion known as "the Moon illusion."

Atmospheric refraction makes things close to the horizon look a little higher than they are, and the effect is greater the lower the object is. Since the bottom of the moon (as seen by the viewer) is lower than the top, its position is refracted upwards more, and so the circular moon appears squashed into an oval.

Part of the reason the moon seems oval at times is that you are used to seeing a full circle of moon, and yet, when the sun is in certain positions, part of the lighted face is where we can't see it, so it looks odd. I was playing with ellipse once, and figured this out. Yes, it was kind of odd-looking, but I don't think the moon's being low in the sky had anything to do with it.

The optical curvature of the atmosphere is greater when you look through it at 'low angles'.