At the entrance to the Heichal, the nivreshet was hung. This was a golden lamp, which was a round decoration fashioned of gold and donated by Queen Helene. At sunrise, the rays of sun would strike the nivreshet, giving the appearance that sparks of light were being emitted by the lamp. Everyone in Jerusalem then knew that the time had arrived to recite the morning Shema (Source: Yoma 37). 
The Ulam Interior
Contents:   Part I,    Part II,    Part III,    Part IV,    Part V,    Part VI,    Part VII