Hi Dieter.
Thanks for your reply. I am aware that there are two Ascheberg's in Germany. I remember hearing from family members that he also was from Westphalia. With the ships log referencing Ascheberg as his city of origin and hearing that he was from Westphalia, this seemed to be a possibility.
I was able to obtain a naturalization certificate for a Frederick Rau that was issued in South Bend, Indiana dated September of 1870. It referenced a departure city of Bremen, Germany. It also indicated that he gave up his allegiance to "Prince William of Prussia" in order to become a US citizen. I do not know whether this was my GGF, but I have never heard of anyone else with that name in the area, and no information searches have ever turned up anyone else with that name.
Dieter, thanks again for your reply.
Bill Rowe