Pennsylvania Avenue is roughly aligned with the angle of the Sirius rising as well. So from the direction of the White House Sirius would appear rising behind the Capitol. But the angle is off by about 2 degrees. Not a lot, but not insignificant either. This leads to the next revelation…

Sirius rises 21.2 degrees south of east in DC with atmospheric refraction taken into account (which makes stars visible when slightly below the horizon). This precisely matches the angle of the line going from the “front porch” of the White House (which is the north side facing away from the National Mall) to the center of the “front porch” of the Capitol on the west side (which is actually the back side). A remarkable alignment and one that I don’t think anyone in the general public has noticed before.

Without atmospheric refraction, the rising angle of Sirius in DC would be 21.7 degrees south of east. This one precisely matches the angle of the line connecting the starting point and the destination of the inaugural parade!