At 06:06 am 20-03-05 -0900, Horace wrote: > Actually it would be turning in sidereal time, maintaining fixed > relationship with the stars.
Quite so. But why let an inconvenient mismatch get in the way of a good story. 8^) > A gyroscope very well gimballed in all axes and oriented in the equatorial > plane should work (though not as a pendulum). A nifty thing about that in > the old days is it could have replaced an accurate clock as the means of > determining longitude. A good gyro, combined with an accurate lunar > ephemieris... A case of two eyes being better than one, eh. <G> > ...to be used for periodic gyro calibration, could have been used > to achieve fairly accurate navigation and mapping. The technological > problems then "merely" consist of achieving frictionless bearings and a > nearly perfect vacuum. That would have really taxed Harrison's workmanship; and talking of lunar thingees, it is interesting that the moon is now acting as a slow pendulum with respect to the earth. Is this because its centre of mass and its centre of gravity with respect to the earth are different and so the compound pendulum has an effective length less than infinity - or is it because the moon is lopsided in some way or other. Cheers Frank Grimer
