Be careful about the shortest path. Of course you and the earth know
that a geodesic arc is the shortest path, cutting nearly a great circle
along the point from A to B. But map distortions give you a different
"view" and when you draw a straight line on a mercator, you have a rhumb
line.
[mailto:sundial-boun...@uni-koeln.de] Namens Brent
Verzonden: donderdag 24 september 2015 22:12
Aan: sundial@uni-koeln.de
Onderwerp: Re: due east photos
I think you can face Mecca from 4 directions:
1. along great circle shortest direction
2. along great circle longest direction
3. along constant compass
Apparently Muslims have a similar problem when determining which way to
pray towards Mecca (Qibla).
This non-scientific website gives a choice of 2 different directions:
https://threesixty360.wordpress.com/2008/09/01/which-direction-is-mecca/
There is more confusion found in the comments at
Well, if you are going to allow compass directions, then that opens the
door to all loxodromes. There are an infnite number of loxodromes that
connect two points on a sphere, if you allow loxodrome paths that travel
more than once around the globe! This gives an infinite number of compass
"an infinite number of compass directions to Mecca"
allahu akbar!
.
On 9/24/2015 2:39 PM, Bill Gottesman wrote:
Well, if you are going to allow compass directions, then that opens
the door to all loxodromes. There are an infnite number of loxodromes
that connect two points on a
I think you can face Mecca from 4 directions:
1. along great circle shortest direction
2. along great circle longest direction
3. along constant compass method shortest direction
4. along constant compass method longest direction
I wonder if it says in Koran to face Mecca in shortest direction?
.
https://www.quora.com/What-is-Richard-Feynmans-sum-over-paths-approach-to-qu
antum-mechanics
Jack
From: sundial [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Brent
Sent: Thursday, September 24, 2015 5:58 PM
To: Bill Gottesman
Cc: Sundials List
Subject: Re: due east photos
'
Subject: RE: due east photos
Maybe it helps to bear in mind that while all triangles on a plane surfaces
contain 180 degrees, this is not true on a sphere. You cannot make a triangle
on a plane surface that has two 90 degree angles because the sides will never
meet.
On a sphere, however
On 17/09/2015 09:31, Fabio nonvedolora wrote:
well said Jack,
flat Earth and similar are unlikely :-)
globe
Fabio
Fabio Savian
fabio.sav...@nonvedolora.it
www.nonvedolora.eu
Paderno Dugnano, Milano, Ita
45° 34' 10'' N, 9° 10' 9'' E, GMT+1 (DST +2)
The comedian Michael Bentine used to have a
Brent--
On Tue, Sep 15, 2015 at 7:47 PM, Brent <bren...@verizon.net> wrote:
> Michael;
>
> Ok, let's make it easier.
>
> On any day I want to stand in my backyard and look due east.
> I don't want to travel anywhere.
>
> Do I look at where the sun will rise on the
Hi Brent--
The paradox involves what you mean by "travel due east'.
If you travel due east, and keep on traveling due east at every point of
your journey, then you will indeed follow a parallel of latitude.
If you were to drive your car in that fashion, always going due east, along
a par
Michael;
Ok, let's make it easier.
On any day I want to stand in my backyard and look due east.
I don't want to travel anywhere.
Do I look at where the sun will rise on the equinox or do I look
slightly to the left of that? (northern hemisphere)
If you tell me to look slightly to the left
> Mark Gingrich wrote:
> Indeed. And here's a curious bit of related trivia: If you
> start due east from *any* latitude and travel a great circle
> route -- i.e. "straight" -- a distance of one quarter of the
> Earth's circumference, you *always* end up on the equator.
At any point on the earth, there is one great circle that
is tangent to your latitude circle. That means that at that
infinitesimally small point, both circles point in the same
direction, i.e due east, but only at that point.
Also note that the plane that cuts the earth at any
latitude
On 15/09/2015 10:34, Brent wrote:
I think we all agree the sun rises (appears to rise) due east on the
equinox.
If the earth stops and the sun stops and I start walking towards the
sun (on the surface of the earth)
I believe I would be walking a straight line - due east.
Ok, it's sunrise
Roger;
You seem to be saying there are /two/ due easts.
How can that be right? Shouldn't there only be one due east?
brent
On 9/15/2015 9:42 AM, Roger W. Sinnott wrote:
Brent,
The “small circle” route is the one that takes you on a curved path,
always toward due east.
You could also
Roger Sinnott wrote:
> You could also start out going due east on a "great circle" route, and in
> that case, as you note, the path would gradually veer southward.
Indeed. And here's a curious bit of related trivia: If you
start due east from *any* latitude and travel a gr
I think we all agree the sun rises (appears to rise) due east on the
equinox.
If the earth stops and the sun stops and I start walking towards the sun
(on the surface of the earth)
I believe I would be walking a straight line - due east.
And I would not be adjusting my direction each step, I
On 15/09/2015 17:42, Andrew Pettit wrote:
Hello
What fun!
Methinks that the confusion arises because the earth is not a “plane”
but a sphere. Mercator tried to project the sphere on to the plane and
had curved lines of latitude.
Another confusion is that there is more than one Halifax ;-)
If I was in halifax at sunrise on the equinox and the earth stopped
rotating and I walked due east (towards the sun) across the ocean
I would end up in Southern Spain and not on my same latitude which is in
Southern France.
So I conclude that latitude lines are not east-west lines.
Correct
They are east-west lines, but they are not straight. They are circles.
On 2015-09-15 12:30, Brent wrote:
If I was in halifax at sunrise on the equinox and the earth stopped
rotating and I walked due east (towards the sun) across the ocean
I would end up in Southern Spain and not on my same
Brent,
The "small circle" route is the one that takes you on a curved path, always
toward due east.
You could also start out going due east on a "great circle" route, and in
that case, as you note, the path would gradually veer southward.
Both of these routes start
Due east is a right angle from north-south. But the 'line' of latitude is not a great circle (except the equator, which is).
So if you keep walking due east, you are really always curving towards the pole.Suppose you lived 1 meter from the North Pole; then you would walk along a circle of 2
uot;. It's
what you draw on a chart. Sailors call it a "rhumb line".
Frank 55N 1W
On 15/09/2015 15:10, Brent wrote:
I'm confused maybe.
I live in the northern hemishpere and anticipating the equinox on the
23rd.
Supposedly the sun will rise due east.
So if due east is a right an
Due east is a right angle from north-south.
Op 15 september 2015 om 16:10 schreef Brent <bren...@verizon.net>:
I'm confused maybe. I live in the northern hemishpere and anticipating the equinox on the 23rd. Supposedly the sun will rise due east. So if due east is a
See also
Martin Gardner - Mathematical Carnival - Ch. 17
Andrew
From: sundial [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Brent
Sent: 15 September 2015 17:30
To: Frank Evans
Cc: sundial
Subject: Re: due east
If I was in halifax at sunrise on the equinox and the earth stopped
ruler East, then rolling the point of contact will make it cross lines
of latitude as varying angles as you get closer to the equator.
Thus, to walk due East (i.e. perpendicular to a North-South line) on the
Earth, after each step you have to recalculate where East is and make a
minute
m: sundial [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Brent
Sent: 15 September 2015 17:30
To: Frank Evans
Cc: sundial
Subject: Re: due east
If I was in halifax at sunrise on the equinox and the earth stopped rotating
and I walked due east (towards the sun) across the ocean
I would end up in Sout
I'm confused maybe.
I live in the northern hemishpere and anticipating the equinox on the 23rd.
Supposedly the sun will rise due east.
So if due east is a right angle from north south and I traveled due east
I would not follow my line of latitude.
I would get further and further south of my
Hello David and all of you east-west seekers,
With Tony Moss's 24 Hr (EoT adjusted) equatorially positioned clock, the hour
hand would be in the meridian of the sun only; but due to its declination, the
sun would usually pass due east and west before or after the hour hand,
depending
Hi David,
The equation you quoted is correct. Cos t = Tan Dec / tan Lat. It is easier to
calculate than it looks with a simple scientific calculator. As simple
program or spreadsheet could easily add the add the equation of time and
longitude to provide a table of clock times for each day of
-Bill Gottesman
n a message dated 9/19/2005 11:44:42 AM Eastern Standard Time, [EMAIL PROTECTED] writes:
Hi David,
The equation you quoted is correct. Cos t = Tan Dec / tan Lat. It is easier to
calculate than it looks with a simple scientific calculator. As simple
program or spreadsheet
-
From: Alexei Pace [EMAIL PROTECTED]
To: sundial@rrz.uni-koeln.de
Sent: Saturday, September 17, 2005 8:05 AM
Subject: RE: Is it possible to determine when the sun is due East West?
On another topic, does anyone have a photo gallery of any new sundials ,
preferably something ���innovative
] Im Auftrag von Roger Bailey
Gesendet: Samstag, 17. September 2005 07:28
An: David Lawrence; sundial@rrz.uni-koeln.de
Betreff: RE: Is it possible to determine when the sun is due East West?
Hello David,
This doesn't answer your original question, the times that the sun is due
east
First of all, my thanks to those people who took the time to reply to
my cry for help on this - and my apologies for a slight delay in
responding, but I had to 'clarify' a few things with the Muslim group.
The following are (I think!) the criteria that they wish to fulfill:
(1) They are not
. It was interesting
to see the evolution of time keeping on this set of dials. Pictures
available on request.
This doesn't answer your original question, the times that the sun is due
east or west. The east west line is easily established with primitive
methods like Indian or Hindu Circles
David,
If this group has religious duties to pray due East or due West then that
religion must halso have the means to determine that direction, you see
that in any culture in the world. So I wonder how they found those
directions before.
It is more or less the same question I had earlier
of
sundial..
Regards,
alex
From:
[EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Th. Taudin Chabot
Sent: Is-Sibt, 17 ta' Settembru
2005 07:58
To: sundial@rrz.uni-koeln.de
Subject: Re: Is it possible to
determine when the sun is due East West?
David,
If this group has religious
Friends,
David Lawrence started with the thread about
finding east or west for the Muslims.
I should say: use a magnetic compass.
I think this also was done in practice aswas
done with portable sundials.
But isn't the direction to Mecca of more
importance? (Qibla)
Then use e.g. a "Mecca
Re: Is it possible to determine when the sun is due
East West?
I wanted to answer to this thread and I needed a
figure.My e-mail to the sundial list didn't pass so I offer my answer for
download at:
http://www.de-zonnewijzerkring.nl/test/mekka.htm
Together with a second figure the file
, and (knowing of my hobby-level
interest in Amateur Astronomy) - I was recently asked if it would
be possible to tell the exact time when the sun is DUE EAST WEST.
There is a local group of Muslim 'asylum-seekers', who have been
moved here from mainland Britain - and (as part of their religious
-Bill
In a message dated 9/16/2005 5:01:34 AM Eastern Standard Time, [EMAIL PROTECTED] writes:
Subj: Is it possible to determine when the sun is due East West?
Date:9/16/2005 5:01:34 AM Eastern Standard Time
From:[EMAIL PROTECTED]
To:sundial@rrz.uni-koeln.de
Received from Internet
you to build this device at the following address:
www.mysundial.ca/sdu/sdu_dialling_buddy.html
Once you have built the device all you have to do is set the arrow to the
latitude where it will be used. The times when the sun is due east and west
is indicated at the Vertical Wall. The day
Hello David,
In no way am I belittling your problem, or the religious group
involved, but I can't help wondering how they determined the exact
times when the sun was due east and west at their previous location.
Or, their locations before that.
Best wishes,
Mac
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