Celestial Navigation on the Spit...

Tuesday, 15 September 2015 

 

I went out on the Spit to try and practice some Star sextant shots prior to the Offshore course in BC. On Tuesday there were some wisps of clouds as the sun was setting and it became evident that this would prevent seeing all the stars that I was targeting to shoot. As it happened I was only able to see and shoot Altair in the observation period before it got too late and the horizon disappeared in the darkness. One star shot is not enough to get a fix.

The wispy clouds do make for a phenomenal sunset.

I could see Altair with the naked eye quite well. Altair came up quickly easily once the altitude had been preset on the sextant.

It made for an challenging exercise as I juggled binoculars, clipboard, compass and sextant. It will be interesting to see how this gets done on a boat out west.

Wednesday, 16 September 2015

This was a clearer evening so I headed to the Spit again - same location and ready to shoot all four stars. It took a while before I got going but after a bit of searching I finally shot all four just as the observation period had ended and the horizon was disappearing in the darkness.

It seemed as if all 4 stars were where they were supposed to be so that was the only assurance that I had properly identified each one. Between lights across the lake and planes coming in, it took a bit of waiting and observing before catching and dropping the right object (star) down to the horizon.

After reducing and plotting the sights, there was no proper fix to be gained with the position lines as compared to the GPS fix of the location. Not sure what was missing - the intercepts were not that great.