Sentence:  It does not concern men who are asleep in their beds, but it is very important to the traveller, whether the moon shines brightly or is obscured. It is not easy to realize the serene joy of all the earth, when she commences to shine <WSD>unobstructedly</WSD>, unless you have often been abroad alone in moonlight nights. 
Meaning of the word marked with <WSD> tags:  Without being obstructed; without being hidden or blocked.