In 1837 he was named officer - in - charge of the depot and began an extensive series of observations of the moon and stars for the purpose of longitude determination .
Gilliss proved himself to be an excellent astronomical observer .
In 1837 Gilliss was named officer - in - charge of the depot and began an extensive series of observations of the moon and stars for the purpose of longitude determination .
Gilliss proved himself to be an excellent astronomical observer .