It is possible, Ebony as well as all dark woods give me fits when it comes to getting all the sanding marks out.
sand the blanks on the lathe while it is turning, then shut off the lathe and sand with the grain or the length of the barrel until you don't see the marks from sanding while the lathe was running. then move on to your next grit of sandpaper. also wipe the blank clean after each grit as particals left behind can cause new scratches.
good luck