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Well, the 1D X would appear to be the camera, but the hard part is lenses.
If the end comes from far above and appears as a point that expands as in gets closer you will want an 800 L, extenders, then a 600 L, then a 400 L then the 70 - 200 L II and finally the 24 - 70 L II.
On the other hand, if we just all go floating off into space you will probably want the same lenses just in reverse order.
Then, if the end comes all at once all across the sky you will only need the 24 - 70.
No matter what, shoot in RAW so you can bring out the best in post processing.