🚀 go-pugleaf

Lowell,

  Your satellite project from the early days might well be a super on-line
project for current physics teachers and their students.  With the current
prediction software and daily keplarian elements updates available also
on-line from NASA, observations could be made from a good portion of the
US, weather permitting, and reported through this listserv.  Could be
interesting.

-Phil Kline,
 Chemistry/Physics Teacher
 Mohawk HS
 Sycamore, OH 44882
 email: pkline@nike.heidelberg.edu


 On Tue, 28 Feb 1995, Lowell Herr wrote:

> > >
> > > Lowell
> > >
> >  You are right about the value of G=6.67 x 10^-11, It was my typo. I did
> >  try to look up a couple of Physics books, but did not get any info. How
> >  accurate can the data be if such a technique(timing the moon(s) of
> >  Mars) to calculate the mass is used. So does that mean that the timing
> >  of the planets can be used to calculate the mass of the sun. Thanks for
> >  your reply....
>
> Yes.  The mass of the Sun can accurately be measure by knowing the orbital
> time and mean radius.  The mass of the Earth was accurately measured back
> in the late '50's and early '60's using satellites.  I forget the name of
> the project but can get it as my brother worked on it.  I was part of a
> team that helped to determine orbits of the early satellites.  It is much
> too long to explain here but readers would sure get a kick out of how it
> was done.
>
> Briefly, we would sit out at night looking up at the sky until we would
> spot a satellite.  Remember, there were very few objects moving around the
> earth in 1958!  Once we spotted a satellite we would look into a monicular
> scope - all 16 spotters looking into scopes as we formed a line of
> viewers, eight on each side of a large metal cross.  When the satellite
> came into view we would press on a buzzer that was connected to a tape
> that recorded WWV time.  If and when the satellite crossed behind the
> large cross we would release the buzzer and then depress it again as the
> satellite emerged from behind the cross.
>
> Knowing the latitude and longitude of our position and the time the
> satellite crossed the position, plus the viewers position in the straight
> line (difficult to explain without a diagram), the tape was sent to the
> Smithsonian as I recall.  Using triangulation with other sites, the orbit
> of the satellite could be determined.  That is the crux of what it was
> like in the early days.
>
> It was a lot of fun.
>
> Lowell
>