Re: [guide-user] "Star" of Bethlehem

Paul Schlyter Apr 5, 2001

From: "Chris Marriott" <chris@...>

>> Perhaps the TT-UT correction used by Guide isn't accurate as
>> far back as 6 BC?
>
> Highly improbable that this would result in an error of hours. The
> uncertainty in "delta T" for 2000 years ago is a few minutes - it's
> certainly not hours!
>
> Presumably Guide can tell you what the "delta T" value is for a given map
> date. For 17th April 6BC my "SkyMap Pro" program uses a delta T value of
> +9117.5 seconds - what does "Guide" use for this date?

Probably a value not very different from yours. But the interesting
part was the deviation of Guide's delta-T from the real delta-T, not
from SkyMap's delta-T :-)

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