The conjunction of Sirius and the Sun does not occur at the same time in all latitudes, and is not constant in the same region for a long period, hence the variation in calendars regarding the limits of the Dog Days. Some say the period of the dog days lasts 20 days before and after the conjunction of Sirius and the Sun.
In 2011 in the Pacific Time Zone, Sirius rises before the Sun on the last day of July, but remains hidden in its glare. When Sirius rises above the eastern horizon at an altitude of 7 degrees it can be seen. This heliacal rising of Sirius occurs August 7, 2011 in San Francisco.
... the heliacal rising: the first visible, though brief, appearance of a star on the eastern horizon before sunrise. On the previous morning, sunlight made the star invisible. When the rising of a star is spoken of, it is usually the heliacal rising that is meant. In ancient Egypt, the helical rising of Sirius coincided with the annual rising of the Nile at Memphis. Index to Time and Calendars / Rising and Setting of StarsSirius at an altitude of less 7 degrees [above the horizon] is hidden from our view by the Sun’s light. Heliacal Rising & Setting of Sirius
The heliacal setting of Sirius (last visible setting of Sirius) in San Francisco occurred May 23, 2011 hence, Sirius is hidden from view for 75 days in San Francisco during 2011.
On the first day of Sirius' reappearance the ancient Egyptians expected an abundant harvest, if the star appeared bright and clear. If Sirius appeared dull and red, a poor harvest would result. What color will Sirius be at its reappearance this year? When will you first see Sirius in the morning sky? Let me know!
