A little check please

Hi guys. Well first of all, I have to say that after years of thinking that
I know one of the most common things, I just found out that I actually don't
so that's why I am freaked out and require a check just to see if I am right
for these basic astronomy questions. All this time I knew that the lines of
longitude stretch from N to S and lines of latitude stretch from E to W.
Then I just discovered that when latitude is measured, it's measured in a
way that I thought that longitude was measured, meaning the measurement of
altitude would be like 20* N and for longitude it would be like 64* E. It
still doesn't make sense to me, why do you have these lines to go from N to
S yet they measure coordinates in E and W. Anyhow here is my assignment, so
can someone tell me if I am right or not. Thanks.

Given resources: It's spring equinox, the Sun is on my meridian at 75* in
the S, my UT clock says it 22:00
What is my longitude, latitude and where should I go in order to go to some
land mass, instead of ice.

2. It's spring equinox meaning that the Sun's ecliptic will cross with the
celestial equator on the celestial sphere. Since I have a watch, both my
day and my night will last 12 hours each equally on this day, and today's
date is most likely to be March 21. The Sun is on my meridian at altitude
of 75* south, meaning that it's noon (12 p.m.) where I am standing at, and
my latitude is 75* south. My watch, which is set to universal time, says it
's 22:00 meaning it's 10 p.m., so I must be behind 10 hours. This means that
my longitude is 10hr times 15*/hr = 150* west of the prime meridian in
Greenwich. My altitude is 75* south, meaning that my latitude is 75* south
as well. Since I have a little map beside me, and since I have to sail to
the nearest land, I should set sail northeast to Venezuela in South America.

Thank you.

For the land part, I meant Chile not Venezuela.

For the land part, I meant Chile not Venezuela.

"Zarkovic" wrote in news:y3Keb.2484$9l5.730@pd7tw2no:

Hi guys. Well first of all, I have to say that after years of thinking
that I know one of the most common things, I just found out that I
actually don't so that's why I am freaked out and require a check just
to see if I am right for these basic astronomy questions. All this
time I knew that the lines of longitude stretch from N to S and lines
of latitude stretch from E to W. Then I just discovered that when
latitude is measured, it's measured in a way that I thought that
longitude was measured, meaning the measurement of altitude would be
like 20* N and for longitude it would be like 64* E.

Altitude is the angular measurement from your local horizon towards your
local zenith. Azimuth is the compass bearing around your local horizon.

The celestial equivalent to latitude and longitude are declination and
right ascension. Declination is equivalent to latitude. i.e it is expressed
in degrees north or south of the celestial equator, versus degress north or
south of the Earth's equator. (The celestial equator is just the Earth's
equator projected into the sky). Right ascension is similar to longitude
but it is measured in time rather than degrees. I.e 24 hours versus 180
degrees east or west of Greenwich.

The other difference is the start position (zero hours) is not measured
from a point on the Earth's surface but from a point in the sky. In
particular RA = 0, Dec = 0 is taken as the point on the celestial equator
that the Sun crosses at the moment of the Vernal equinox (i.e marks the
Northern hemisphere spring equinox). This point is sometimes just referred
to as the Vernal Equinox but is also called "The first point of Aries".
This is a historic definition as the Vernal Equinox is currently in Pisces
due to the precession that has occurred since Ptolemy's day. It takes about
26,000 years for the Vernal Equinox to do a complete circuit. This is why
the RA and DEC of a star are always only valid for a specific epoch. If you
know what epoch (date) the RA and DEC were specified for, you can adjust
(precess) the coordinates for the current date. Most planetarium programs
do that automatically.

Have a go at your homework question yourself :-).

Llanzlan.

SNIP

"Zarkovic" wrote in news:y3Keb.2484$9l5.730@pd7tw2no:

Hi guys. Well first of all, I have to say that after years of thinking
that I know one of the most common things, I just found out that I
actually don't so that's why I am freaked out and require a check just
to see if I am right for these basic astronomy questions. All this
time I knew that the lines of longitude stretch from N to S and lines
of latitude stretch from E to W. Then I just discovered that when
latitude is measured, it's measured in a way that I thought that
longitude was measured, meaning the measurement of altitude would be
like 20* N and for longitude it would be like 64* E.

Altitude is the angular measurement from your local horizon towards your
local zenith. Azimuth is the compass bearing around your local horizon.

The celestial equivalent to latitude and longitude are declination and
right ascension. Declination is equivalent to latitude. i.e it is expressed
in degrees north or south of the celestial equator, versus degress north or
south of the Earth's equator. (The celestial equator is just the Earth's
equator projected into the sky). Right ascension is similar to longitude
but it is measured in time rather than degrees. I.e 24 hours versus 180
degrees east or west of Greenwich.

The other difference is the start position (zero hours) is not measured
from a point on the Earth's surface but from a point in the sky. In
particular RA = 0, Dec = 0 is taken as the point on the celestial equator
that the Sun crosses at the moment of the Vernal equinox (i.e marks the
Northern hemisphere spring equinox). This point is sometimes just referred
to as the Vernal Equinox but is also called "The first point of Aries".
This is a historic definition as the Vernal Equinox is currently in Pisces
due to the precession that has occurred since Ptolemy's day. It takes about
26,000 years for the Vernal Equinox to do a complete circuit. This is why
the RA and DEC of a star are always only valid for a specific epoch. If you
know what epoch (date) the RA and DEC were specified for, you can adjust
(precess) the coordinates for the current date. Most planetarium programs
do that automatically.

Have a go at your homework question yourself :-).

Llanzlan.

SNIP

Only one line of latitude is a great circle, meaning that its center
coincides with the center of the earth, and that is the zero degree line, or
the equator. Every line of longitude is, however, a great circle, again
with its center coincident with the center of the earth.

Latitude varies from 90 deg N, through 0 deg at the equator, to 90 deg S.
These lines form a locus of points that coincide with the earth's axis.

Longitude varies from Greenwich, 0 deg, to 180 deg at the International Date
Line, back to 0 deg.

Hope this helped, although it didn't assist with the homework. . .

Neal
"Zarkovic" wrote in message
news:y3Keb.2484$9l5.730@pd7tw2no...
Hi guys. Well first of all, I have to say that after years of thinking
that
I know one of the most common things, I just found out that I actually
don't
so that's why I am freaked out and require a check just to see if I am
right
for these basic astronomy questions. All this time I knew that the lines
of
longitude stretch from N to S and lines of latitude stretch from E to W.
Then I just discovered that when latitude is measured, it's measured in a
way that I thought that longitude was measured, meaning the measurement of
altitude would be like 20* N and for longitude it would be like 64* E. It
still doesn't make sense to me, why do you have these lines to go from N
to
S yet they measure coordinates in E and W. Anyhow here is my assignment,
so
can someone tell me if I am right or not. Thanks.

Given resources: It's spring equinox, the Sun is on my meridian at 75* in
the S, my UT clock says it 22:00
What is my longitude, latitude and where should I go in order to go to
some
land mass, instead of ice.

2. It's spring equinox meaning that the Sun's ecliptic will cross with the
celestial equator on the celestial sphere. Since I have a watch, both my
day and my night will last 12 hours each equally on this day, and today's
date is most likely to be March 21. The Sun is on my meridian at altitude
of 75* south, meaning that it's noon (12 p.m.) where I am standing at, and
my latitude is 75* south. My watch, which is set to universal time, says
it
's 22:00 meaning it's 10 p.m., so I must be behind 10 hours. This means
that
my longitude is 10hr times 15*/hr = 150* west of the prime meridian in
Greenwich. My altitude is 75* south, meaning that my latitude is 75* south
as well. Since I have a little map beside me, and since I have to sail to
the nearest land, I should set sail northeast to Venezuela in South
America.

Thank you.

Only one line of latitude is a great circle, meaning that its center
coincides with the center of the earth, and that is the zero degree line, or
the equator. Every line of longitude is, however, a great circle, again
with its center coincident with the center of the earth.

Latitude varies from 90 deg N, through 0 deg at the equator, to 90 deg S.
These lines form a locus of points that coincide with the earth's axis.

Longitude varies from Greenwich, 0 deg, to 180 deg at the International Date
Line, back to 0 deg.

Hope this helped, although it didn't assist with the homework. . .

Neal
"Zarkovic" wrote in message
news:y3Keb.2484$9l5.730@pd7tw2no...
Hi guys. Well first of all, I have to say that after years of thinking
that
I know one of the most common things, I just found out that I actually
don't
so that's why I am freaked out and require a check just to see if I am
right
for these basic astronomy questions. All this time I knew that the lines
of
longitude stretch from N to S and lines of latitude stretch from E to W.
Then I just discovered that when latitude is measured, it's measured in a
way that I thought that longitude was measured, meaning the measurement of
altitude would be like 20* N and for longitude it would be like 64* E. It
still doesn't make sense to me, why do you have these lines to go from N
to
S yet they measure coordinates in E and W. Anyhow here is my assignment,
so
can someone tell me if I am right or not. Thanks.

Given resources: It's spring equinox, the Sun is on my meridian at 75* in
the S, my UT clock says it 22:00
What is my longitude, latitude and where should I go in order to go to
some
land mass, instead of ice.

2. It's spring equinox meaning that the Sun's ecliptic will cross with the
celestial equator on the celestial sphere. Since I have a watch, both my
day and my night will last 12 hours each equally on this day, and today's
date is most likely to be March 21. The Sun is on my meridian at altitude
of 75* south, meaning that it's noon (12 p.m.) where I am standing at, and
my latitude is 75* south. My watch, which is set to universal time, says
it
's 22:00 meaning it's 10 p.m., so I must be behind 10 hours. This means
that
my longitude is 10hr times 15*/hr = 150* west of the prime meridian in
Greenwich. My altitude is 75* south, meaning that my latitude is 75* south
as well. Since I have a little map beside me, and since I have to sail to
the nearest land, I should set sail northeast to Venezuela in South
America.

Thank you.

"Zarkovic" wrote in news:y3Keb.2484$9l5.730@pd7tw2no:

Hi guys. Well first of all, I have to say that after years of thinking
that I know one of the most common things, I just found out that I
actually don't so that's why I am freaked out and require a check just
to see if I am right for these basic astronomy questions. All this
time I knew that the lines of longitude stretch from N to S and lines
of latitude stretch from E to W. Then I just discovered that when
latitude is measured, it's measured in a way that I thought that
longitude was measured, meaning the measurement of altitude would be
like 20* N and for longitude it would be like 64* E. It still doesn't
make sense to me, why do you have these lines to go from N to S yet
they measure coordinates in E and W. Anyhow here is my assignment, so
can someone tell me if I am right or not. Thanks.

Given resources: It's spring equinox, the Sun is on my meridian at 75*
in the S, my UT clock says it 22:00
What is my longitude, latitude and where should I go in order to go to
some land mass, instead of ice.

2. It's spring equinox meaning that the Sun's ecliptic will cross with
the celestial equator on the celestial sphere. Since I have a watch,
both my day and my night will last 12 hours each equally on this day,
and today's date is most likely to be March 21. The Sun is on my
meridian at altitude of 75* south, meaning that it's noon (12 p.m.)
where I am standing at, and my latitude is 75* south. My watch, which
is set to universal time, says it 's 22:00 meaning it's 10 p.m., so I
must be behind 10 hours. This means that my longitude is 10hr times
15*/hr = 150* west of the prime meridian in Greenwich. My altitude is
75* south, meaning that my latitude is 75* south as well. Since I have
a little map beside me, and since I have to sail to the nearest land,
I should set sail northeast to Venezuela in South America.

Thank you.



Yes. You are 150W 75S. Head NW (to Chile as you say).

Martin Lewicki

"Zarkovic" wrote in news:y3Keb.2484$9l5.730@pd7tw2no:

Hi guys. Well first of all, I have to say that after years of thinking
that I know one of the most common things, I just found out that I
actually don't so that's why I am freaked out and require a check just
to see if I am right for these basic astronomy questions. All this
time I knew that the lines of longitude stretch from N to S and lines
of latitude stretch from E to W. Then I just discovered that when
latitude is measured, it's measured in a way that I thought that
longitude was measured, meaning the measurement of altitude would be
like 20* N and for longitude it would be like 64* E. It still doesn't
make sense to me, why do you have these lines to go from N to S yet
they measure coordinates in E and W. Anyhow here is my assignment, so
can someone tell me if I am right or not. Thanks.

Given resources: It's spring equinox, the Sun is on my meridian at 75*
in the S, my UT clock says it 22:00
What is my longitude, latitude and where should I go in order to go to
some land mass, instead of ice.

2. It's spring equinox meaning that the Sun's ecliptic will cross with
the celestial equator on the celestial sphere. Since I have a watch,
both my day and my night will last 12 hours each equally on this day,
and today's date is most likely to be March 21. The Sun is on my
meridian at altitude of 75* south, meaning that it's noon (12 p.m.)
where I am standing at, and my latitude is 75* south. My watch, which
is set to universal time, says it 's 22:00 meaning it's 10 p.m., so I
must be behind 10 hours. This means that my longitude is 10hr times
15*/hr = 150* west of the prime meridian in Greenwich. My altitude is
75* south, meaning that my latitude is 75* south as well. Since I have
a little map beside me, and since I have to sail to the nearest land,
I should set sail northeast to Venezuela in South America.

Thank you.



Yes. You are 150W 75S. Head NW (to Chile as you say).

Martin Lewicki

Llanzlan Klazmon The 15th wrote:

Altitude is the angular measurement from your local horizon towards your
local zenith. Azimuth is the compass bearing around your local horizon.

Quibble: A compass bearing is measured from magnetic north, while
azimuth is measured from geographic/celestial north, i.e. the point
where the meridian crosses the horizon. A compass bearing must be
corrected for "variation" (and also "deviation" caused by local
magnetic fields) in order to derive the "true" bearing.

--
Odysseus