Locating a non continuous shape

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Hi,

I'd like to make an exploration autopilot for a game I love, elite dangerous, in python. Because I'm a python dev, It's fun, and I'll learn a lot about image processing.

I've found many tutorial aimed at locating a shape, however those were "continous" shape, like circles, squares, etc.

I'm looking for this shape (the blue dot can move) :

This compass is used to locate where you need to go, my aim is to extract the direction from it's center and the blue dot.

This compass is always in the lower left corner but not always at the same place, the camera moves a little bit when you move plus the environment can change it's color background.

Example - flying below a star :

Example - regular space flying :

What would you do to locate, extract and read the compass?

Thanks.

Ps : I'm coding in python 2.7