Naval Academy reinstates celestial navigation

that is insane, not teaching celestial.

from the article: "In the event that we had to go into a national emergency, we would probably have to shut the GPS down because it can be used by potential enemies,"
that happened many times during dessert storm, and probably many times since than too.

as a former single handed offshore sailor I always kept a sextant and tables aboard... a storm can be very disorienting and you could be on the rocks (or worse, in a shipping channel) in a heartbeat.
I used both Loran and GPS back in 1992... we were very POed when Loran was dropped... Navy boats have become a hazard

ok, desierto

Peter Ehlert, post: 351390, member: 60 wrote: ok, desierto

Desierto, cool. New word for me.

My limited vocabulario would probably have come up with arena caliente.

I have often wondered what modern day surveyors would do if GPS went down. I think many have become so dependent on GPS that they would not know how to observe an azimuth, run a good control net, etc. Be honest...how many could establish an azimuth accurate to 5"?

I also think NGS is wrong to "abandon" existing control established by conventional methods, but that is another issue....they do not adjust older control unless it was observed by GPS, even though there are quite a few stations which were part of a triangulation or traverse net and now have GPS positions.

John Hamilton, post: 351456, member: 640 wrote: how many could establish an azimuth accurate to 5"?

I'd have to crack open some books and do a whole lot of practicing first.

John Hamilton, post: 351456, member: 640 wrote: I have often wondered what modern day surveyors would do if GPS went down. I think many have become so dependent on GPS that they would not know how to observe an azimuth, run a good control net, etc. Be honest...how many could establish an azimuth accurate to 5"?

It wouldn't take long for anyone to learn azimuth by Polaris, so long as you have good crosshair illumination and make sure to get the sign right on the Laplace correction. I ran into trouble with what may be crosshair illumination parallax (?) using an external light.

Solar allows work at more convenient times IF you have a solar filter and maybe a right-angle eyepiece, or a non-EDM theodolite for projection method, but the timing is so critical that it would take a lot of practice to get 5" reliably.

John Hamilton, post: 351456, member: 640 wrote: I also think NGS is wrong to "abandon" existing control established by conventional methods, but that is another issue....they do not adjust older control unless it was observed by GPS, even though there are quite a few stations which were part of a triangulation or traverse net and now have GPS positions.

I've also wondered why they don't readjust the triangulation network using the old observations with new GPS positions where available. It seems like that would increase the usefulness of those other stations. It would take increased funding for NGS, I suppose.

Having a Plan B with more passive control instead of total reliance on GPS would indeed be comforting.

Us greyhairs are one major solar event away from a major promotion;^)

Bill93, post: 351465, member: 87 wrote: I've also wondered why they don't readjust the triangulation network using the old observations with new GPS positions where available.

I wonder if the error estimates for those old observations is so large compared with GPS positions that it's just not worth going to the effort.

Aw heck all you have to do is pull out your K&E Ephemeris and (oh yea what year is this?).

John Hamilton, post: 351456, member: 640 wrote: I have often wondered what modern day surveyors would do if GPS went down.

Northing = 5000.0000
Easting = 5000.0000
Elevation = 100.00

Q.E.D.

James Fleming, post: 351758, member: 136 wrote: Northing = 5000.0000
Easting = 5000.0000
Elevation = 100.00

Q.E.D.

Does "QED" mean, "prove me wrong"?

No, it means you can't. It's Latin for "end of discussion", lol.