There appear to be two vessels named OMEGA who came to Adelaide in 1851.
1. OMEGA from Liverpool 5 - 04 1851 via Plymouth 19/4/1851 - Captain S. Potter, arrived Port Adelaide on 28-07-1851
2. OMEGA from Bourbon arrived Port Adelaide 26 08 1851 R (no passengers ?)
The following is a combined list - from the SA REGISTER, from Rob Janmaat's list on The Shiplist
and from transcription of both the Certificate of Final Departure and Nominal List of Emigrants held in the Mortlock Library in Adelaide SA.