I understand the basic procedures while using celestial navigation at sea with a sextant. But, I have no idea about the basic practices and procedures of celestial navigation when using a bubble-octant while airborne over an ocean in the 1930s & ’40s. For example: On a ship the sextant is used at dawn and dusk to obtain a site while the natural horizon and celestial object are visible a the same time… does this mean that a bubble-octant site can be made all night long??? Also, I’ve read that the bubble-octant was the worst option for attempting celestial sites while navigating on the land before GPS was invented. If this in true… why? I know that the bubble-octant was limited in usefulness… but how limited was it really??? How was it done on a daily basis? The vintage user manuals aren’t clear about the very basic principles and practices of aeronautical bubble-octant navigating.