Irangate colonel straight up? (5)

I believe the answer is:

north

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'straight up?' is the definition.
(I've seen this in another clue)

I can't explain the rest of the clue.

(Other definitions for north that I've seen before include "usually featured at the top of the charts?" , "A 24 [STAR]" , "Compass point at 0 or 360 degrees" , "Magnetic or true?" , "Top of most maps" .)

I've seen this clue in the Sydney Morning Herald.

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