You should also look into Tom Tursi's MDschool.com where he wrote his own book on celestial navigation. He offers this course via his MDschool.com program run out of Rock Hall, MD.
(ps: I built the MDschool web site a long time ago)
mdschool.com/courseDe.htm
I sailed to Bermuda in 2000 aboard IP45 Halimeda with Tom Tursi as captain and he was teaching his celestial navigation course as well. Taking sightings offshore on a moving yacht is a real challenge! Tom allowed us to also plot our own tries at this, as long as we did not mess with his celestial plots. We had a hard time plotting ourselves onto the paper which was 600 miles x 600 miles! Tom's plots would be right next to our GPS digital plots.
The exciting aspect was having Bermuda come over the horizon right were Tom projected it to be using only a sextant. To see that at sea was a real treat.
So if you get a chance to work with Tom Tursi of the MDschool.com, I would take that course first.
Hayden