celestrial navigation anyone?
 

Really?

http://americanhistory.si.edu/collec...dnumber=451517

Catalogue number:
AF*59057-N
Inscriptions:
"U.S. ARMY AIR CORPS / AIRCRAFT OCTANT / TYPE NO. A-7 SERIAL NO. A0-42-132 /
SPECIFICATION NO. 94-27747A / ORDER NO. AC-17520 / MFR'S ASSY. DWG. NO.
3003-B / BENDIX AVIATION CORPORATION / PIONEER INSTRUMENT DIVISION / BENDIX,
NEW JERSEY, U.S.A." and "MFR'D UNDER ONE OR MORE OF THE /FOLLOWING PATENT
NOS. / 1556994 1674550 1970543 / 2221152 DES. 85912 / BENDIX AVIATION
CORPORATION / PIONEER INSTRUMENT DIVISION / BENDIX, NEW JERSEY, U.S.A."



Another aircraft octant:

http://americanhistory.si.edu/collec...dnumber=123408

There are a number of aircraft octants for sale he

http://www.paxp.com/mac/navtrak/sextants.html#used_m

And another octant:

http://americanhistory.si.edu/collec...dnumber=451519



Are you certain they were really sextants on those naval aircraft? We used
an octant aboard a P-2.

In maritime history octants were the predecessor of sextants. Octants have
several distinct advantages over the sextant for use in aircraft. If you are
experienced in the use of both you can really understand why.

Perhaps your memory is not reliable.

celestrial navigation anyone?
 

"Capt. JG" wrote in message
news:89ydnfGc1fm5XJHVnZ2dnUVZ_vOdnZ2d@bayareasolut ions...
"Dennis Pogson" wrote in message
...

They look great on the mantleshelf. A wow at cocktail parties. Buy
plenty
of Brasso.

Dennis.

I'd like to keep mine aboard... a good talking point for students.

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




Just don't look through it backwards, upside down or leave the lens cap on
it.

http://www.galaksija.com/znakovi/clinton_binoculars.jpg

celestrial navigation anyone?
 

"Roger Helio" wrote in message
...

"Wayne.B" wrote in message
...

It might be possible but I doubt it. There used to be a sextant
designed for aircraft navigation in WW II that used an artificial
horizon of sorts but those guys were happy to know where they were
within 20 miles or so.

That was not a sextant. It was called an octant.

Here's one:

http://www.icarusbooks.com/images/1458.jpg
That is not an octant. It looks like a bubble sextant as used on aircraft..
An octant is exactly the same as a sextant except that is is constructed to
read to 45 degrees against a sextant's 60.
A sextant can therefore measure a wider angle than an octant.
.. I have an octant that my grandfather used. It is made of
ebony and has ivory engraved scale read with a vernier, but in all essential
respects is identical to a sextant.

celestrial navigation anyone?
 

Capt. JG wrote:
"Jeff" wrote in message ...
Capt. JG wrote:
...
The disadvantage is that each position depends upon the previous one, so
that small errors may build up to be large ones.
No, you can go a number of days referencing the last fix.

Don't understand... yes, you can go a number of days, but after that it
seems to me it would start to get way off.

If you start with a fix, you don't accumulate error each day, only when
you change stars. In other words, as long as you can use the same set
of stars, you only have one sight's worth of error. In theory, if you
have a large number of stars, you can go quite a while, since three good
LOPs would count as a new fix.

celestrial navigation anyone?
 

"Jeff" wrote in message ...
If you start with a fix, you don't accumulate error each day, only when
you change stars. In other words, as long as you can use the same set of
stars, you only have one sight's worth of error. In theory, if you have a
large number of stars, you can go quite a while, since three good LOPs
would count as a new fix.


Please don't say "fix" in front of Capt. JG. He might be inclined to suffer
a relapse.

--
Gregory Hall

celestrial navigation anyone?
 

"Jeff" wrote in message ...
Capt. JG wrote:
"Jeff" wrote in message ...
Capt. JG wrote:
...
The disadvantage is that each position depends upon the previous one,
so that small errors may build up to be large ones.
No, you can go a number of days referencing the last fix.

Don't understand... yes, you can go a number of days, but after that it
seems to me it would start to get way off.

If you start with a fix, you don't accumulate error each day, only when
you change stars. In other words, as long as you can use the same set of
stars, you only have one sight's worth of error. In theory, if you have a
large number of stars, you can go quite a while, since three good LOPs
would count as a new fix.


Yes, absolutely. My point was that 1) you're going to have to use multiple
sets and 2) if you're inaccurate in your observation, this will translate
into larger and larger errors later.... well, unless you only make one
error.

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

celestrial navigation anyone?
 

"Edgar" wrote in message
...

"Roger Helio" wrote in message
...

"Wayne.B" wrote in message
...

It might be possible but I doubt it. There used to be a sextant
designed for aircraft navigation in WW II that used an artificial
horizon of sorts but those guys were happy to know where they were
within 20 miles or so.

That was not a sextant. It was called an octant.

Here's one:

http://www.icarusbooks.com/images/1458.jpg
That is not an octant. It looks like a bubble sextant as used on
aircraft..
An octant is exactly the same as a sextant except that is is constructed
to
read to 45 degrees against a sextant's 60.
A sextant can therefore measure a wider angle than an octant.
. I have an octant that my grandfather used. It is made of
ebony and has ivory engraved scale read with a vernier, but in all
essential
respects is identical to a sextant.



It came from this page:

http://www.icarusbooks.com/nonpaper.htm

Click on the link CS1458 "Aircraft octant".

Here's one on sale at eBay:

http://cgi.ebay.com/WWII-NAVY-OCTANT...QQcmdZViewItem

Here's a US Navy manual on them:

http://cgi.ebay.com/SEXTANT-OCTANT-M...2em118Q2el1247

Here's another manual:

http://cgi.ebay.com/Link-Bubble-Sext...2em118Q2el1247

Amelia Earhardt used an octant.

Eddie Rickenbacker used one on his B-17. Octants were standard issue on
B-17s.

All US military aviation navigators used octants.


What type of navigation uses a radiant? A radiant is an "octant" that covers
360 degrees. That will certainly stump all of you since no one even knew of
the existence of an octant. (Hint: octants are top secret, only I know about
them!). The term "sextant" was used for these devices so as not to confuse
those of minimal mental capacity, apparently for good reason.

celestrial navigation anyone?
 

wrote in message
...
On Mon, 21 Apr 2008 14:10:51 -0700, "Capt. JG"
wrote:

"Jeff" wrote in message ...
Capt. JG wrote:
"Jeff" wrote in message ...
Capt. JG wrote:
...
The disadvantage is that each position depends upon the previous one,
so that small errors may build up to be large ones.
No, you can go a number of days referencing the last fix.

Don't understand... yes, you can go a number of days, but after that it
seems to me it would start to get way off.

If you start with a fix, you don't accumulate error each day, only when
you change stars. In other words, as long as you can use the same set
of
stars, you only have one sight's worth of error. In theory, if you have
a
large number of stars, you can go quite a while, since three good LOPs
would count as a new fix.


Yes, absolutely. My point was that 1) you're going to have to use multiple
sets and 2) if you're inaccurate in your observation, this will translate
into larger and larger errors later.... well, unless you only make one
error.

I think the typo in the subject line is making more and more sense. :')

Heh... and apparently no one else noticed it.

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

celestrial navigation anyone?
 

"Capt. JG" wrote in message
news:6bmdnauSu96riJDVnZ2dnUVZ_hmtnZ2d@bayareasolut ions...
wrote in message
...
On Mon, 21 Apr 2008 14:10:51 -0700, "Capt. JG"
wrote:

"Jeff" wrote in message ...
Capt. JG wrote:
"Jeff" wrote in message ...
Capt. JG wrote:
...
The disadvantage is that each position depends upon the previous
one,
so that small errors may build up to be large ones.
No, you can go a number of days referencing the last fix.

Don't understand... yes, you can go a number of days, but after that
it
seems to me it would start to get way off.

If you start with a fix, you don't accumulate error each day, only when
you change stars. In other words, as long as you can use the same set
of
stars, you only have one sight's worth of error. In theory, if you
have a
large number of stars, you can go quite a while, since three good LOPs
would count as a new fix.


Yes, absolutely. My point was that 1) you're going to have to use
multiple
sets and 2) if you're inaccurate in your observation, this will translate
into larger and larger errors later.... well, unless you only make one
error.

I think the typo in the subject line is making more and more sense. :')

Heh... and apparently no one else noticed it.



What a twit!

Only those with self-imposed blinders in the form of kill files didn't
notice where I picked up on it and called you an idiot on day one.

Wilbur Hubbard

celestrial navigation anyone?
 

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.

I have a Carl Zeiss "Yachtmaster" which does not have any artificial
horizon and have yet to see a marine sextant that does. Bought it
second hand in its wooden box 20 years ago for NZ$450.

For sight reduction tables for sun, moon and stars I now use my O2
phone/PDA with a neat little programme (Bruce, please note the CORRECT
and civilised spelling of "programme"). Yes, I know, a lightning
strike could take that out too but I throw it in the oven with the
some of the other gear when lightning gets too close. Anyway, there is
always the backup of donning knee pads and grovelling to God.

About once a year I get the urge to keep up my skills in case of such
as a lightning strike, turn off all instruments for a few days and
take sights.

Peter