Chr. Eckhardt Hansen, San Francisco 1905

In october 1905 Constance Marie Hansen left Kristiania (Oslo)by SS Hellige Olav. She was going to her husband Chr. Eckhardt Hansen, 1505 Leavenworth street, San Francisco, Ca. I am unable to find them in any census so I need some help. Constance Marie's emmigration protocol can be found at this links: http://digitalarkivet.uib.no/cgi-win/webcens.exe?slag=visbase&filnamn=EMIOSLO&gardpostnr=175309&merk=175309#ovre Her arrival at Ellis Island can also be found in that database. According to Norwegian census of 1900 they was both using the name "Aarstad" as surename but they probably both had been living at a farm named Aarstad for a while. Chr(ristian)'s fathers name was probably Hansen, but why he has taken the name Eckhardt Hansen has no explanation.