AN ACCURATE GALACTIC N-H MAP OF THE NORTH ECLIPTIC POLE

The Galactic HI column density was measured at 21' angular resolution over an 8 degrees x 9 degrees region centered on the north ecliptic po le. Over the region N-H varies smoothly between 3 x 10(20) atoms cm(-2 ) and 8 x 10(20) atoms cm(-2); some structure is seen over most of the map on an 0.5-1 degrees scale. There are other possible sources of in terstellar opacity in this direction which may add an equivalent 10(20 ) cm(-2) of HI. We evaluate the effect of uncertainties in the HI colu mn density on implied X-ray fluxes of extragalactic objects.