Re: precession of mercury

On Wed, 24 Dec 2008 01:54:01 -0800 (PST), Jerry
<Cephalobus_alienus@xxxxxxxxxxx> wrote:

On Dec 24, 12:42 am, hw@..(Dr. Henri Wilson) wrote:

Did you find anything about the orbit, Jerry?

(sigh)
As I have repeated AGAIN AND AGAIN, Hipparcos was stuck in
a highly elliptic geostationary transfer orbit because of
failure of the apogee boost engine. The original intent
was for a geostationary orbit "which would have kept the
satellite in a fixed position with respect to a single
ground station. From this orbit, as opposed to low-Earth
orbits, the Earth obscures only a small portion of the
celestial sphere being scanned."
http://www.rssd.esa.int/SA/HIPPARCOS/docs/vol2_all.pdf

The operational orbit was a far cry from what was intended:
? perigee height: 526 km
? apogee height: 35 900 km
? orbital period: 640 min
? eccentricity: 0.72
? inclination: 6.8 deg
? ascending node: 105 deg
? argument of perigee: 214 deg

In short, the whole thing was a complete stuff up.
You didn't mention that it eclipses every orbit.

During the operational lifespan of the satellite, its orbit
decayed from due to repeated passages through the atmosphere
at perigee. This complicated the analysis considerably.
Repeated passage through the Van Allen belts was hard on the
equipment and the solar panels. The high speeds required
much greater precision in orbit determination because of the
fast changing aberration at perigee.

Now will you SNAP OUT OF YOUR FANTASYLAND WANDERINGS and
start paying attention to actual facts as opposed to your
imaginings?

The whole process could be simplified if the thing was sent into a circular
orbit in the ecliptic plane. However as long as the axis of precession of the
axis of rotation is perpendicular to that plane, a small tilt in the orbit
plane wont cause much of a problem or error.

Obvoiusly neither you nor Paul can get it into your head that aberration can be
virtually eliminated from parallax measurements if the telescope used does not
rotate around its own axis. If it is pointed at a particular star all year, the
positions of other stars in the vicinity change according to their relative
distances from the central star. Light speed shold not affect the outcome.

I am aware that Hipparcos does not operate like this directly because of its
scanning method...but the principle still exists.

The more I read about the Hipparcos mission, the less faith I have in its
published figures.

Jerry



Henri Wilson. ASTC,BSc,DSc(T)

www.users.bigpond.com/hewn/index.htm.

......
.

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