Alpha Centauri's Declination is -60d 50m. So, let's round that to -61 for simplicity and that means that at a northern latitude of +29 degrees, Alpha Cen would be right on the horizon. Its that "must add up to 90 degrees" thing. When I am at one of my best Arizona sites (+34), it is only down 5 degrees.
Clear skies; Steve Coe
-------------------- 150mm 6" f/8 Celestron Refractor on Sirius Mount
80mmED 3" f/7.5 Orion Refractor
Author "Deep Sky Observing" Springer-Verlag
Author "Nebulae and How to Observe Them" Springer
New Canon Xt astrocamera with Hutech modification