toadatrix May 27, 2004
--- In guide-user@yahoogroups.com, "wcappwca" <wcapp@h...> wrote:
> --- In guide-user@yahoogroups.com, Bill J Gray <pluto@p...> wrote:
> > What I'd suggest doing is to tell Guide that, for dates
from
> 2004
> > on, Delta-T is increasing linearly at its current slow rate.
That
> > means hitting Alt-J and entering the following:
> >
> > DELTA_T=2004,2100:64.574,18.62,0
> >
>
> I tried this and noticed a small point:
>
> since T=(y-2000)/100 the above is equivalent to
> 64.574 + (y-2000)*0.1862; for 2004 this is 65.3118
>
> since the value for 2004 should be 64.574, I believe the constant
> should be changed to 64.574 - (4*0.1862) = 63.8292
> 63.8292 + (y-2000)*0.1862; for 2004 this is 64.574
>
> Also, my copy of Guide apparently doesn't have the table entry for
> 2004 yet so I changed the 2004 to 2002 and my final formula was
>
> DELTA_T=2002,2100:63.829,18.62,0
>
> Bill A.