Paul Schlyter Jun 21, 2000
> Hi Guiders.There are different ways to compute the size of the Earht's shadow.
>
> I found little mystery about lunar eclipse of 16 July.
>
> Astronomical Ephemeris tells as :
> Prnumbra enterd : 10h46m4 (UT)
> Umbra entered : 11h57m0
> Totality begins : 13h01m8
>
> Guide's [Tables] -> [Lunar eclipses] tells as :
> Prnumbra enterd : 10h47m (UT)
> Umbra entered : 11h56m
> Totality begins : 13h01m
>
> I displayed lunar eclipse on Guide Lebel-12, animating 5-sec steps.
> Prnumbra enterd : 10h51m20s (UT)
> Umbra entered : 12h00m20s
> Totality begins : 13h04m50s
>
> It seems Earth's shadow is little small.
> I turned lunar displaying 'Bitmap' to 'Shaded' .
> I found Guide has 8 steps Penumbra.
> And no--8 Penumbra is edge of Umbra Astronomical Ephemeris use to
> calculate.