Subject: What is the lunar-distance method of calculating longitude?

I have spent hours searching the internet, trying to find out about the 
lunar-distance method of determining longitude.  Apparently it involves 
measuring the moon's altitude, and the angular distance between the moon 
and the sun or a star.  I canot find information about exactly how this is 
done and if it can be done today( I know the technique was used 100 years 
ago)  I need information about the method, and reference for further 
reading. Thank you

Re: What is the lunar-distance method of calculating longitude?