WASHINGTON D. C. ASTRONOMY
Washington D.C. and many of it's buildings and monuments are laid out according to the cardinal directions with the streets running due NS and EW. In the map of Washington D.C. below, due east is up and the star chart shows the constellation of Orion rising due east over Washington D.C., as it has done every day for the past two hundred years. Orion's belt points towards Sirius, the brightest star in the sky, and while Orion is rising and low on the eastern horizon, Orion's belt is vertical, pointing to Sirius below. In the diagram, Sirius is the bright star below Orion near the upper edge of the map of Washington D.C. The bright star above Orion is Aldebran, the alpha star in the constellation of Taurus.
The axis of the ancient Egyptian temple of Isis at Dendera was oriented to the rising point of Sirius on the eastern horizon. The angle of Pennsylvania Avenue from the White House to the Capitol building has pointed to the rising point of Sirius at the latitude of Washington D.C. since the avenue was laid out over 200 years ago. Looking southeast down Pennsylvania Avenue, Sirius rises directly over the Capitol building. Higher in the sky, Orion is also above Sirius and above the Capitol building from the viewpoint of Pennsylvania Avenue as Sirius rises over the horizon.
The diagram above also shows the sun below the horizon on the left side of the diagram. In relation to the fixed stars, the sun rises later each day due to the rotation of the earth around the sun. The sun rises just after Sirius at the latitude of Washington D.C. on August 15. This is known as the heliacal rising of Sirius. Prior to this time of year, the sun is above or too close to the horizon for the rising of the star to be visible. Ancient Egyptians based their calendar on the heliacal rising of Sirius, which signaled the onset of the annual flooding of the Nile. Christians celebrate the Assumption of the Virgin Mary on August 15, linking the Assumption to the first appearance of Sirius/Isis in the sky just before dawn.
The star spangled headdress on the statue on top of the Capitol dome suggests a stellar symbolism consistent with the alignment of Pennsylvania Avenue targeting the rising point of Sirius above the Capitol building. The picture below is a close up of the statue while it was down for restorations in 1993.
Orion has also set due west at the latitude of Washington D.C. for the past two hundred years. From the viewpoint of the Capitol building, Orion sets right behind the Washington Monument. Setting in the west, Orion's belt is horizontal, pointing to Sirius setting south of due west. From the viewpoint of the Capitol building, Sirius sets over the Potomac River, on the alignment of Maryland Avenue. From the viewpoint of the Capitol building, Aldebran sets over the White House, on the alignment of Pennsylvania Avenue.