Oh Yes, it can be done. Two years ago on a 30day South Pacific cruise on HAL they had the "star lady". She is a professional astronamer and a guest lecturer. At night she would hold classes on deck where she would point out the constellations and the Southern Cross.
It was socool. I have been told that now she does this on HAL all the time. We are taking the same cruise again in Jan maybe she will be there again.