Is this correct

Is it correct that a star that is overhead at the equator will show a red
shift in its spectral lines when viewed from the retreating position and a
corresponding blue shift from the advancing position.

Thank you from Paul

"Paulps" wrote in message
...
Is it correct that a star that is overhead at the equator will show a red
shift in its spectral lines when viewed from the retreating position and a
corresponding blue shift from the advancing position.

Yes, but the speeds are so slow that the shift will be too tiny to notice.

Clear Skies

Chuck Taylor
Do you observe the moon?
Try http://groups.yahoo.com/group/lunar-observing/

Are you interested in understanding optics?
Try http://groups.yahoo.com/group/ATM_Optics_Software/

************************************

Wasn't it CLT who wrote:
"Paulps" wrote in message
...
Is it correct that a star that is overhead at the equator will show a red
shift in its spectral lines when viewed from the retreating position and a
corresponding blue shift from the advancing position.

Yes, but the speeds are so slow that the shift will be too tiny to notice.

It's a very significant factor if you're looking for things like star
wobble caused by extrasolar planets.

Extrasolar planet spotters are often looking for changes in star motions
that are of the order of 10 metres per second, whereas the Earth moves
along its orbit at over 30 kilometres per second. They have to allow for
the red and blue shifts caused by the Earth's orbit and also for the
shifts caused by the motion of the observatory as the Earth rotates at
about 400 meters per second.

--
Mike Williams
Gentleman of Leisure

Sorry, but I am a bit confused by the two replies from the same person ?
a) yes, but the shifts will be to tiny to notice.
b) yes, its very significant to extrasolar planet spotters.
So I guess the answer is yes?
Thanks paul

Wasn't it CLT who wrote:
"Paul" wrote in message
...
Is it correct that a star that is overhead at the equator will show a
red
shift in its spectral lines when viewed from the retreating position
and a
corresponding blue shift from the advancing position.

Yes, but the speeds are so slow that the shift will be too tiny to
notice.

It's a very significant factor if you're looking for things like star
wobble caused by extrasolar planets.

Extrasolar planet spotters are often looking for changes in star motions
that are of the order of 10 metres per second, whereas the Earth moves
along its orbit at over 30 kilometres per second. They have to allow for
the red and blue shifts caused by the Earth's orbit and also for the
shifts caused by the motion of the observatory as the Earth rotates at
about 400 meters per second.

--
Mike Williams
Gentleman of Leisure

"Paulps" wrote in message
...
Sorry, but I am a bit confused by the two replies from the same person ?
a) yes, but the shifts will be to tiny to notice.
b) yes, its very significant to extrasolar planet spotters.
So I guess the answer is yes?
Thanks paul

Mike is correct. I was thinking of most observers not noticing it. It is
noticable, but only if you go to more effort than most.

Clear Skies

Chuck Taylor
Do you observe the moon?
Try http://groups.yahoo.com/group/lunar-observing/

Are you interested in understanding optics?
Try http://groups.yahoo.com/group/ATM_Optics_Software/

************************************

Wasn't it CLT who wrote:
"Paul" wrote in message
...
Is it correct that a star that is overhead at the equator will show a
red
shift in its spectral lines when viewed from the retreating position
and a
corresponding blue shift from the advancing position.

Yes, but the speeds are so slow that the shift will be too tiny to
notice.

It's a very significant factor if you're looking for things like star
wobble caused by extrasolar planets.

Extrasolar planet spotters are often looking for changes in star motions
that are of the order of 10 metres per second, whereas the Earth moves
along its orbit at over 30 kilometres per second. They have to allow for
the red and blue shifts caused by the Earth's orbit and also for the
shifts caused by the motion of the observatory as the Earth rotates at
about 400 meters per second.

--
Mike Williams
Gentleman of Leisure