retrograde motion

Isn't mars going to retrograde in motion as earth overtakes it in August?

"bwhiting" wrote in message
...
Mick,
of course.....all the outer planets retrograde (move westward
across the backdrop of stars) during opposition.
Mars began retrograding on July 30 and becomes stationary
in RA on Sept 29 at 14 hr UT. And resumes direct motion.

[So its moved from 22 hr 56 min on July 30 to a point
22hr 16 min on Sept 29.]
Clear Skies,
Tom W.


Ok..why doesn't become stationary at opposition on Aug 27 when earth is
parallel?

"bwhiting" wrote in message
...
Mick,
of course.....all the outer planets retrograde (move westward
across the backdrop of stars) during opposition.
Mars began retrograding on July 30 and becomes stationary
in RA on Sept 29 at 14 hr UT. And resumes direct motion.

[So its moved from 22 hr 56 min on July 30 to a point
22hr 16 min on Sept 29.]
Clear Skies,
Tom W.


Ok..why doesn't become stationary at opposition on Aug 27 when earth is
parallel?

Mick wrote:

Ok..why doesn't become stationary at opposition on Aug 27 when earth is
parallel?

At opposition the Earth is passing by Mars so the red planet appears to
be going "backwards". In fact, since we're on parallel paths the
retrograde motion is maximized. And because it's closer to us then it
seems to be backing up even faster than when the distance is greater.
So Aug. 27 is roughly when it's in the middle of its retrograde loop and
losing ground the fastest. Not until we're moving more in a line away
from it rather than passing it by will it resume its apparent direct
motion.

Mike Simmons

Mick wrote:

Ok..why doesn't become stationary at opposition on Aug 27 when earth is
parallel?

At opposition the Earth is passing by Mars so the red planet appears to
be going "backwards". In fact, since we're on parallel paths the
retrograde motion is maximized. And because it's closer to us then it
seems to be backing up even faster than when the distance is greater.
So Aug. 27 is roughly when it's in the middle of its retrograde loop and
losing ground the fastest. Not until we're moving more in a line away
from it rather than passing it by will it resume its apparent direct
motion.

Mike Simmons

So, Claudius, have you forgotten to explain your epicycles?

;^)

"Mike Simmons" wrote

At opposition the Earth is passing by Mars so the red planet appears to
be going "backwards". In fact, since we're on parallel paths the
retrograde motion is maximized. And because it's closer to us then it
seems to be backing up even faster than when the distance is greater.
So Aug. 27 is roughly when it's in the middle of its retrograde loop and
losing ground the fastest. Not until we're moving more in a line away
from it rather than passing it by will it resume its apparent direct
motion.

Mike Simmons

So, Claudius, have you forgotten to explain your epicycles?

;^)

"Mike Simmons" wrote

At opposition the Earth is passing by Mars so the red planet appears to
be going "backwards". In fact, since we're on parallel paths the
retrograde motion is maximized. And because it's closer to us then it
seems to be backing up even faster than when the distance is greater.
So Aug. 27 is roughly when it's in the middle of its retrograde loop and
losing ground the fastest. Not until we're moving more in a line away
from it rather than passing it by will it resume its apparent direct
motion.

Mike Simmons