R.A direction?

Can someone enlighten me please?

I seem unable to find the answer to the following question.

Where do you 'point' the R.A Drive when the Setting Circle is set to Zero?

I have read it should point East to Aries and also due South.

I know how to use the R.A but am stumped by the setting up. I have an EQ5
mount with a polar alignment scope.

TIA

Clear skies

Martin A

--
Remove star to reply

Right Ascension corresponds to longitude on the Earth (east-west
measurement), with 0 hours R.A. being a _line_ that extends from the
celestial poles through the point in Aries where the ecliptic crosses the
equator. (It's like the 0° longitude line that was arbitrarily chosen to
pass through Greenwich, England.)

http://skyandtelescope.com/howto/bas...icle_562_1.asp

When setting up an equatorially mounted telescope, the best procedure is to
polar align it (get the scope's polar axis parallel to the Earth's), set the
declination to +90 while the scope is still pointing toward Polaris, then
point it at a bright star of known R.A. and Dec. and calibrate the other
circle there.



"Stargazer" wrote in message
...
Can someone enlighten me please?

I seem unable to find the answer to the following question.

Where do you 'point' the R.A Drive when the Setting Circle is set to Zero?

I have read it should point East to Aries and also due South.

I know how to use the R.A but am stumped by the setting up. I have an EQ5
mount with a polar alignment scope.

TIA

Clear skies

Martin A

--
Remove star to reply

Right Ascension corresponds to longitude on the Earth (east-west
measurement), with 0 hours R.A. being a _line_ that extends from the
celestial poles through the point in Aries where the ecliptic crosses the
equator. (It's like the 0° longitude line that was arbitrarily chosen to
pass through Greenwich, England.)

http://skyandtelescope.com/howto/bas...icle_562_1.asp

When setting up an equatorially mounted telescope, the best procedure is to
polar align it (get the scope's polar axis parallel to the Earth's), set the
declination to +90 while the scope is still pointing toward Polaris, then
point it at a bright star of known R.A. and Dec. and calibrate the other
circle there.



"Stargazer" wrote in message
...
Can someone enlighten me please?

I seem unable to find the answer to the following question.

Where do you 'point' the R.A Drive when the Setting Circle is set to Zero?

I have read it should point East to Aries and also due South.

I know how to use the R.A but am stumped by the setting up. I have an EQ5
mount with a polar alignment scope.

TIA

Clear skies

Martin A

--
Remove star to reply

Correction: the ecliptic crosses the celestial equator in Pisces now
instead of Aries, due to precession. So that's really the starting point
for R.A.



"Bill Nunnelee" wrote in message
hlink.net...
Right Ascension corresponds to longitude on the Earth (east-west
measurement), with 0 hours R.A. being a _line_ that extends from the
celestial poles through the point in Aries where the ecliptic crosses the
equator. (It's like the 0° longitude line that was arbitrarily chosen to
pass through Greenwich, England.)

http://skyandtelescope.com/howto/bas...icle_562_1.asp

When setting up an equatorially mounted telescope, the best procedure is
to
polar align it (get the scope's polar axis parallel to the Earth's), set
the
declination to +90 while the scope is still pointing toward Polaris, then
point it at a bright star of known R.A. and Dec. and calibrate the other
circle there.



"Stargazer" wrote in message
...
Can someone enlighten me please?

I seem unable to find the answer to the following question.

Where do you 'point' the R.A Drive when the Setting Circle is set to
Zero?

I have read it should point East to Aries and also due South.

I know how to use the R.A but am stumped by the setting up. I have an
EQ5
mount with a polar alignment scope.

TIA

Clear skies

Martin A

--
Remove star to reply

Correction: the ecliptic crosses the celestial equator in Pisces now
instead of Aries, due to precession. So that's really the starting point
for R.A.



"Bill Nunnelee" wrote in message
hlink.net...
Right Ascension corresponds to longitude on the Earth (east-west
measurement), with 0 hours R.A. being a _line_ that extends from the
celestial poles through the point in Aries where the ecliptic crosses the
equator. (It's like the 0° longitude line that was arbitrarily chosen to
pass through Greenwich, England.)

http://skyandtelescope.com/howto/bas...icle_562_1.asp

When setting up an equatorially mounted telescope, the best procedure is
to
polar align it (get the scope's polar axis parallel to the Earth's), set
the
declination to +90 while the scope is still pointing toward Polaris, then
point it at a bright star of known R.A. and Dec. and calibrate the other
circle there.



"Stargazer" wrote in message
...
Can someone enlighten me please?

I seem unable to find the answer to the following question.

Where do you 'point' the R.A Drive when the Setting Circle is set to
Zero?

I have read it should point East to Aries and also due South.

I know how to use the R.A but am stumped by the setting up. I have an
EQ5
mount with a polar alignment scope.

TIA

Clear skies

Martin A

--
Remove star to reply

Thanks Bill

Now i understand a lot more. Funny how you spend ages wondering about
something and then WHAM!! the understanding sinks in :-)

Clear skies

Martin A
"Bill Nunnelee" wrote in message
hlink.net...
Correction: the ecliptic crosses the celestial equator in Pisces now
instead of Aries, due to precession. So that's really the starting point
for R.A.



"Bill Nunnelee" wrote in message
hlink.net...
Right Ascension corresponds to longitude on the Earth (east-west
measurement), with 0 hours R.A. being a _line_ that extends from the
celestial poles through the point in Aries where the ecliptic crosses
the
equator. (It's like the 0° longitude line that was arbitrarily chosen
to
pass through Greenwich, England.)

http://skyandtelescope.com/howto/bas...icle_562_1.asp

When setting up an equatorially mounted telescope, the best procedure is
to
polar align it (get the scope's polar axis parallel to the Earth's), set
the
declination to +90 while the scope is still pointing toward Polaris,
then
point it at a bright star of known R.A. and Dec. and calibrate the other
circle there.



"Stargazer" wrote in message
...
Can someone enlighten me please?

I seem unable to find the answer to the following question.

Where do you 'point' the R.A Drive when the Setting Circle is set to
Zero?

I have read it should point East to Aries and also due South.

I know how to use the R.A but am stumped by the setting up. I have an
EQ5
mount with a polar alignment scope.

TIA

Clear skies

Martin A

--
Remove star to reply

Thanks Bill

Now i understand a lot more. Funny how you spend ages wondering about
something and then WHAM!! the understanding sinks in :-)

Clear skies

Martin A
"Bill Nunnelee" wrote in message
hlink.net...
Correction: the ecliptic crosses the celestial equator in Pisces now
instead of Aries, due to precession. So that's really the starting point
for R.A.



"Bill Nunnelee" wrote in message
hlink.net...
Right Ascension corresponds to longitude on the Earth (east-west
measurement), with 0 hours R.A. being a _line_ that extends from the
celestial poles through the point in Aries where the ecliptic crosses
the
equator. (It's like the 0° longitude line that was arbitrarily chosen
to
pass through Greenwich, England.)

http://skyandtelescope.com/howto/bas...icle_562_1.asp

When setting up an equatorially mounted telescope, the best procedure is
to
polar align it (get the scope's polar axis parallel to the Earth's), set
the
declination to +90 while the scope is still pointing toward Polaris,
then
point it at a bright star of known R.A. and Dec. and calibrate the other
circle there.



"Stargazer" wrote in message
...
Can someone enlighten me please?

I seem unable to find the answer to the following question.

Where do you 'point' the R.A Drive when the Setting Circle is set to
Zero?

I have read it should point East to Aries and also due South.

I know how to use the R.A but am stumped by the setting up. I have an
EQ5
mount with a polar alignment scope.

TIA

Clear skies

Martin A

--
Remove star to reply

Bill Nunnelee wrote:

Correction: the ecliptic crosses the celestial equator in Pisces now
instead of Aries, due to precession. So that's really the starting point
for R.A.

The vernal equinox is often called the "first point of Aries",
though, also marking the starting point for the "tropical zodiac" and
serving as the reference for positions in "ecliptic longitude".

--
Odysseus

Bill Nunnelee wrote:

Correction: the ecliptic crosses the celestial equator in Pisces now
instead of Aries, due to precession. So that's really the starting point
for R.A.

The vernal equinox is often called the "first point of Aries",
though, also marking the starting point for the "tropical zodiac" and
serving as the reference for positions in "ecliptic longitude".

--
Odysseus