It may be of interest to note that more members of the Østern family from the present Bærum (then Asker) emigrated on the Zephyr in 1853, where they are all simply listed as Olsen: Gullik Olsen and Karen Engebretsdatter Østern and their daughter (8) Olava Gulliksdatter Østern and Christian Olsen Østern. See Gulliks letter from Lansing, Iowa Feb. 14, 1854.
Sorry to intrude on your topic but I have a particular interest in passenger #56 Olaug Halvorsdatter ae 23 who also took part in the 3 April 1853 voyage of the Zephyr. She may be a person of interest but I would like to find more about her. In your post you list "Gullick's letter" as a source--where does one find this letter? Are any other passengers from the Zephyr mentioned?
Sorry, Olaug Halvorsdatter is unknown to me. When Gullik Olsen Østern wrote his first letter home on Feb. 14 the next year, he did not write about the passage or other passengers, just his own family. The letter is in the first volume of Fra Amerika til Norge (Oslo, 1992). This an edition of immigrant letters I am editing and the fifth volume will be published this year. I believe the first one is out of print. Orm Øverland