celestrial navigation anyone?
 

Can you navigate (lat and long) at night with a sextant and a compass, but
without a nautical almanac, sight reduction tables, the time of day, and
without knowing the names of the stars? The sextant has an error, but you
don't know what it is, just that it's off. You can keep your modern watch,
but you just replaced the battery and the time is wrong.

Does someone own a sextant? What model? I'm thinking about picking one up.

--
"j" ganz @@
www.sailnow.com

celestrial (celestrial? How about celestial?) navigation anyone?
 

IDIOT!!!

celestrial navigation anyone?
 

Dutton wrote in message ...
On Sun, 20 Apr 2008 11:26:00 -0700, "Capt. JG"
wrote:

Can you navigate (lat and long) at night with a sextant and a compass, but
without a nautical almanac, sight reduction tables, the time of day, and
without knowing the names of the stars? The sextant has an error, but you
don't know what it is, just that it's off. You can keep your modern watch,
but you just replaced the battery and the time is wrong.

Are you talking about finding one location with one measurement or by
taking several measurements over a period of time? What degree of
error is acceptable? What a screwball question - do you even
understand what you are asking?

Get a cheap one, you probably will never master it as an instrument
and never understand the mathematics behind it.

http://www.jbs.org/node/163

Dutton


You're another sockpuppet asshole, given the link you posted.... nothing to
say, with a lot of time on your hands. You're quite pathetic.

Keep changing identities if it makes you feel more like a man.

--
"j" ganz @@
www.sailnow.com

celestrial navigation anyone?
 

On Sun, 20 Apr 2008 11:26:00 -0700, "Capt. JG"
wrote:

Can you navigate (lat and long) at night with a sextant and a compass, but
without a nautical almanac, sight reduction tables, the time of day, and
without knowing the names of the stars? The sextant has an error, but you
don't know what it is, just that it's off. You can keep your modern watch,
but you just replaced the battery and the time is wrong.

I assume this is a quiz? You can use a sextant to measure horizontal
angles and take relative shore bearings, other than that I think
you're out of luck. You can not take star sights at night (no
horizon), only at twilight.


Does someone own a sextant? What model? I'm thinking about picking one up.

I've owned this one for years and people have crossed oceans with it:

http://tinyurl.com/6fdkfr

It works but I prefer my GPS chartplotter.

celestrial navigation anyone?
 

On Sun, 20 Apr 2008 13:12:44 -0600, Dutton wrote:

Get a cheap one, you probably will never master it as an instrument
and never understand the mathematics behind it.

http://www.jbs.org/node/163

Dutton

Dutton relied on Bowditch.

celestrial navigation anyone?
 

"Capt. JG" wrote:

Does someone own a sextant? What model? I'm thinking about picking
one up.

I still have a new Davis MK 15 for sale.

Lew

celestrial navigation anyone?
 

"Wayne.B" wrote in message
...
On Sun, 20 Apr 2008 11:26:00 -0700, "Capt. JG"
wrote:

Can you navigate (lat and long) at night with a sextant and a compass, but
without a nautical almanac, sight reduction tables, the time of day, and
without knowing the names of the stars? The sextant has an error, but you
don't know what it is, just that it's off. You can keep your modern watch,
but you just replaced the battery and the time is wrong.

I assume this is a quiz? You can use a sextant to measure horizontal
angles and take relative shore bearings, other than that I think
you're out of luck. You can not take star sights at night (no
horizon), only at twilight.


Does someone own a sextant? What model? I'm thinking about picking one up.

I've owned this one for years and people have crossed oceans with it:

http://tinyurl.com/6fdkfr

It works but I prefer my GPS chartplotter.



Yes, it's a quiz and it's possible...

Not sure what you mean about not being able to use it at night... What about
the artificial horizon common on modern sextants?

http://en.wikipedia.org/wiki/Sextant

I'm somewhat familiar with the Davis models... thinking about playing around
with the 25.


--
"j" ganz @@
www.sailnow.com

celestrial navigation anyone?
 

"Lew Hodgett" wrote in message
news:z3NOj.3364$aq4.2434@trnddc02...

"Capt. JG" wrote:

Does someone own a sextant? What model? I'm thinking about picking one
up.

I still have a new Davis MK 15 for sale.

Lew




Hey Lew... haven't forgot... I think I'm going to get one as a gift, so....

--
"j" ganz @@
www.sailnow.com

celestrial navigation anyone?
 

"Capt. JG" wrote:

Hey Lew... haven't forgot... I think I'm going to get one as a gift,
so....

Send the 'giver' my way.

Everybody makes out.

Lew

celestrial navigation anyone?
 

"Capt. JG" wrote in message
news:J8ednTRMl5onF5bVnZ2dnUVZ_gqdnZ2d@bayareasolut ions...
Can you navigate (lat and long) at night with a sextant and a compass, but
without a nautical almanac, sight reduction tables, the time of day, and
without knowing the names of the stars? The sextant has an error, but you
don't know what it is, just that it's off. You can keep your modern watch,
but you just replaced the battery and the time is wrong.

I say that you cannot.
Firstly because at night you probably cannot see exactly where the horizon
is.Even if you got an aeronautical sextant with a bubble level they are very
hard to read on a boat if it is at all rough
Secondly because you cannot derive longitude without an accurate watch.


Does someone own a sextant? What model? I'm thinking about picking one up.

You do not say what you want it for. For use aboard or just as a talking
point at home?.
You can get various plastic sextants that do a good enough job for use on a
small boat where pinpoint accuracy is hard to achieve.
But a proper sextant is a thing of beauty and mine is a Kelvin Hughes dating
from 1959 which is in pristine condition in its box with all accessories. I
take the odd reading with it from time to time to keep my hand in in case
both my chartplotter and my DR on paper charts fail me. Mine is a
micrometer type but retains the silver engraved scale which is somewhat
overkill for a micrometer since you only need to use the scale to read whole
degrees. But it is very nice to look at an inlaid silver scale.
Vernier sextants are older and are collectable antiques now and regrettably
mostly end up in museums or hanging on someone's wall.
There are a lot of authentic looking but purely decorative ones about which
are not suitable for navigation. Make sure yours comes with an authentic
test certificate.