NavList:

I made it to Southampton, UK !

Thank you very much Frank for your comments and additional information. It looks like I need to learn much more about Lunars, so I am looking forward to attending your next course available.

Just as final comments about the Atlantic crossing, I would like to add the following:

When practicing celestial navigation, sometimes we tend to focus too much on the final results accuracy. Although high accuracy is always a rewarding experience, during this crossing I also focused on other aspects of sailing where celestial navigation can help.

Every night, when the ship calculated position, speed and heading I calculated the next day’s sunrise time and azimuth.  Later, with the estimated LHA at sunrise (actually at nautical twilight) I checked the optimal starts to observe from table 249 vol 1.

The morning after I checked the time of sunrise and also checked with the manual compass the local magnetic variation with the sunrise azimuth calculated the previous night. Both the sunrise time and azimuth tests worked pretty well, but because of weather I could not see all the stars available from table 249. 

Using the magnetic compass was a challenge of this big metal ship, because depending on what part of the ship I was, the compass error (considering true GPS heading and magnetic variation) could go from a few degrees at the ship’s stern to up to 25 degrees from my room balcony in the middle of the ship.

During the morning, based on the estimated position, speed and heading I calculated the meridian passage time, and this also worked well.

In the afternoon, I repeated the same exercise to calculate the sunset time and azimuth. 

In celestial navigation we talk a lot about great circle distances, so I also brought onboard two charts of the north Atlantic, one with a Mercator projection and one with a Gnomonic projection. Every 12 hours I plotted the actual ship’s GPS position on both charts. The objective of this exercise what to visually see how on a Mercator chart the ship course was a curved line and on a Gnomonic chart it was close to a direct line.

Finally, I did at least a couple of manual sight reductions of the sun, moon, planets and stars by using the nautical almanac, table 249 and universal plotting sheet without using a calculator. The objective here was to remain proficient with this technique.

Thanks everyone again for all your comments.