Hi Lawrence,

That 3200 +/- 1800 figure came from the initial Hipparcos reductions.
With the more recent (2007) reduction of Hipparcos data, the distance
estimate changed to 1410 +/- 200 light-years.

If you want "new" Hipparcos data to appear in Guide, you have two
choices. One is to wait for Guide 9 (more info to appear on the Web site
shortly; I've received user manuals, am awaiting the replicated DVDs,
and hope to post a page on the Web site describing what's in it today or
tomorrow, and to be shipping copies once the DVDs actually get here.)

If you're less patient, take a look here...

http://www.projectpluto.com/update8e.htm#new_hipp

...which describes how to download the new Hipparcos data; Guide 8
will then automatically use it when showing 'more info'.

-- Bill

Lawrence wrote:

> By chance I looked up the distance of Deneb shown by Guide: 3200+-1800
> light years.
> The same star is quoted on a web site as being 1425 LY away.
>
> I wonder which datum is correct?
>
> Lawrence Harris