Using the US Naval Observatory " Sun or Moon Rise / Set Table for One Year " calculator, sunrise on the morning of 28 August 1859 sunrise was 05 : 06GMT . The Kew Observatory was still 21 minutes from sunrise and the Solar Flare Effect would not have been registered by the self-recording magnetographs at the Kew Observatory.
22.
The splitting effect is antisymmetric along the line-of-sight, but symmetric transverse to the line of sight, so the transverse component of the field can only be measured up to a factor of-1 : there is a "'180?ambiguity "'in vector magnetograph measurements of portion of the magnetic field that is perpendicular to the line of sight of the instrument.
23.
In 1859 a self-recording magnetometer of United States manufacture, based on the designed of Charles Brooke, was built by the Coast Survey and the Smithsonian Institution at a magnetic observatory on the grounds of the Smithsonian Institution in Washington DC . The Smithsonian report also noted that the Toronto Magnetic and Meteorological Observatory had a self-registering magnetograph in 1850, which was described by General John Henry Lefroy, in Silliman's Journal, May, 1850.
