One minute of Longitude--at your Latitude?
 

Bart Senior wrote:
How long is a minute of Longitude--at your Latitude?

And what is the formula to calcuate it?

OZ, although your posts are mostly negative, for you it
would not be a negative number.
..

Sorry, I misunderstood the question. But in the process met an online
community of sailors! So I am happy.

Some of you wanted to know more about where I sail. I and my wife sail
in Chennai (formerly known as Madras) on the south eastern coast of
India. We have two sailing clubs here. One is the Royal Madras Yacht
Club (94 years old!) and one is the Tamilnadu Sailing Association (4
years old). We are members of both the clubs and sail from either.
Anyway both clubs are adjacent to each other.

We sail outside the harbour in the Bay of Bengal. General conditions
are 10 to 15 Ks of wind this time of the year. In another fortnight it
will go up to between 20 and 25 and we will be in for a season of
squalls. We will be having good swells too. About 2 to 3 metres. Not
much of tides though. We get to sail 365 days in a year! Temperatures
soar to a 112 F in the peak of summers and winters are a pleasant 80 to
85!

We have about 25 to 30 boats on the water on the weekends. And that
includes a clutch of Optis, Enterprises, Lasers and the couple of
Yachts (Maxi 77) I had mentioned. Will load up some pics this week and
let you all know.

Any one of you ever visits this part of the world? for work or
pleasure? Welcome all anyway!

Ravi

One minute of Longitude--at your Latitude?
 

One minute of Longitude--at your Latitude?
 

h. We get to sail 365 days in a year! Temperatures
soar to a 112 F in the peak of summers and winters are a pleasant 80 to
85!

We have about 25 to 30 boats on the water on the weekends. And that
includes a clutch of Optis, Enterprises, Lasers and the couple of
Yachts (Maxi 77) I had mentioned. Will load up some pics this week and
let you all know.

Any one of you ever visits this part of the world? for work or
pleasure? Welcome all anyway!

Ravi

Welcome Ravi,

Your weather and sailing sounds allot like Texas.
we have many lasers, stars, ect...here as well

Welcome to ASA..if your ever in Texas on business or even pleasure you
are two most welcome, with your wife to.

Is it true that there is two Indias, Hindu and Muslim?

Joe

One minute of Longitude--at your Latitude?
 

Making things overly complex is half the fun! Don't you find it interesting
that the oblateness is something you can observe?

But I'll admit I don't throw in an oblateness correction while doing
chartwork.



wrote in message
oups.com...

Using your figures it still works out to less than 1%
difference. Certainly close enough to approximate as
a sphere and avoid making the problem overly complex.

Jeff wrote:
You're being a bit free and easy with the math. Although the
curvature is small, the length of a minute of latitude varies from
1842.9 meters at the equator and 1861.57 at the poles. For the
nautical mile, many countries had their own version, the current
convention is 1852 meters. This is not enough of a discrepancy
(usually) to ruin your day, but with a GPS is should be easily
noticeable.

wrote:
Bart Senior wrote:
How long is a minute of Longitude--at your Latitude?
And what is the formula to calcuate it?


One minute of arc is 1 nautical mile where ever you are. The earth is
not a sphere, there is about a 1% difference between the values at the
poles. Close enough for us to call in a sphere.

One minute of Longitude--at your Latitude?
 

"Joe" wrote
| Is it true that there is two Indias, Hindu and Muslim?



Dumb question, Joe. Let's talk about sailing. Not politics or religion. What does religion matter when it comes to sailing?


Cheers,
Ellen

One minute of Longitude--at your Latitude?
 

Hi Ravi! I was so pleased to read your post.
So it is still the 'Royal' Madras YC.- that is nice because now that you
guys are independent I thought you would have done away with the 'Royal'
prefix!
I visited the Royal Madras YC in 1946 as an engineering officer on the 10000
ton cruiser HMS Glasgow which at the time was engaged in 'showing the flag'
around British territories around the Indian Ocean, following the end of the
war.
We would arrive and lay on a party aboard for local dignitaries and their
families. All took place on the quarterdeck under the shadow of the 6" guns.
The Royal Marine band would be playing during the evening.
.. The stern windlass was converted into a roundabout for the kids.
Our ship was very smart because as soon as the war in the Far East was
over we got rid off the grey and repainted her in the pre-war East Indies
fleet colours, white hull and yellow funnels. We floodlit her at night too.
Looked really good.
I have a photo of myself and a friend sitting on a jetty in Madras watching
a turtle swimming in the water.
We were based in Trincomalee and that is another place I would love to
return to, but sadly it is a war zone at present
Regards
Edgar


wrote in message
oups.com...
Sorry, I misunderstood the question. But in the process met an online
community of sailors! So I am happy.

Some of you wanted to know more about where I sail. I and my wife sail
in Chennai (formerly known as Madras) on the south eastern coast of
India. We have two sailing clubs here. One is the Royal Madras Yacht
Club (94 years old!) and one is the Tamilnadu Sailing Association (4
years old). We are members of both the clubs and sail from either.
Anyway both clubs are adjacent to each other.

We sail outside the harbour in the Bay of Bengal. General conditions
are 10 to 15 Ks of wind this time of the year. In another fortnight it
will go up to between 20 and 25 and we will be in for a season of
squalls. We will be having good swells too. About 2 to 3 metres. Not
much of tides though. We get to sail 365 days in a year! Temperatures
soar to a 112 F in the peak of summers and winters are a pleasant 80 to
85!

We have about 25 to 30 boats on the water on the weekends. And that
includes a clutch of Optis, Enterprises, Lasers and the couple of
Yachts (Maxi 77) I had mentioned. Will load up some pics this week and
let you all know.

Any one of you ever visits this part of the world? for work or
pleasure? Welcome all anyway!

Ravi

One minute of Longitude--at your Latitude?
 

"Dave" wrote
| I think you got that backward, Bart. A minute of Longitude is always 1 NM.
| That's why you always measure distance by going to the side of the chart
| rather than the top or bottom. It's the length of a minute of latitude that
| varies with what latitude you're at, getting shorter as your latitude
| increases from the equator.


You know, I was thinking the same thing. But then I realized I might not know.
They call them parallels of latitude because they stay the same distance apart.
But the longitude lines get closer and closer together the closer to the north and
south pole they get. At the very north and south pole there's no miles at all between
them. So if that's true then the miles are different on each latitude. They're only
one mile long at the equator. That's why I haven't said a word till now. It's all very
confusing.


Cheers,
Ellen

One minute of Longitude--at your Latitude?
 

A minute of longitude is measured East West, and read off
the top or bottom a typical chart.

"Dave" wrote

said:

For longitude lines which converge at the poles things are different.
At the poles a minute of longitude is impossibly short and approaches
zero as you approach the pole.

On second thought, I'll accept your formulation, Bart. When I say one
minute
of longitude, I'm thinking one minute on a longitude line. But I think
you're correct that a minute "of" longitude should properly be regarded as
a
minute measured along a parallel of latitude.

One minute of Longitude--at your Latitude?
 

I can think of two ways God enters into religion.

First, God sails an Ericson.

Second, anyone who has crossed an ocean and seen how
insignificant humans are on the scale of an ocean, will come
to believe in God.

and Third. Joe's question is not without interest.

"Ellen MacArthur" wrote

"Joe" wrote
| Is it true that there is two Indias, Hindu and Muslim?

Dumb question, Joe. Let's talk about sailing. Not politics or religion.
What does religion matter when it comes to sailing?
Cheers,
Ellen

One minute of Longitude--at your Latitude?
 

Ellen has it right. Latitude is measured from the equator.
Lines can there for be parallel and equally spaced. One
minute of longitude will vary by the distance to the equator.

However, if you follow a line of latitude around the earth
the length is a function of latitude. i.e. at 60 deg South it
is quicker than at the equator.

Longitude lines are all the same lenght and converge.

"Dave" wrote

"Bart Senior" .@. said:
How long is a minute of Longitude--at your Latitude?
And what is the formula to calcuate it?

I think you got that backward, Bart. A minute of Longitude is always 1 NM.
That's why you always measure distance by going to the side of the chart
rather than the top or bottom. It's the length of a minute of latitude
that
varies with what latitude you're at, getting shorter as your latitude
increases from the equator.