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Re: (meteorobs) Re; Lunar impacts
Sturat,
I am not guessing. I teach this stuff to future NASA types. It takes three
gyros if they are all orthongonal in their orientation.
>Terry Richardson wrote:
>
>> >David & all,
>> >> Surely the HST could watch the moon for impacts. Although it is
>> down to two gyros from six, two should be enough for the
>> >Hubble to get a fix on the moon.
>>
>> Actually it is three. To fix a point in space you need 3 coordinates, x, y,
>> z and hence three gyros.
>> The Hubble is defunct without repair.
>
>Terry,
> Are you guessing, like me?
>
> If you have two co-ordinates, you have the third, as the perpendicular of
>the plane formed by the two you have.
>
> It may be that the two remaining gyros are the same axis, which would mean
>no second co-ordinate, hence no third co-ordinate.
>
> On further thought, I think a good telescope (eg HST) might be able to
>pick up lunar impacts on the lit side of the moon, but perhaps more by
>observing the shadow of the dust cloud than the impact itself. This would be
>more obvious with long shadows near the terminator.
>
> Stuart
>
> In Astronomy Veritas
> (shaddup, and pass the Vino!)
>
>
>
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