Art Carlson
Wrote:
(snip)..
>Given the key word
>"heliacal rising", I have been able to find the definition and some
>discussions on the Net. I find it surprising that this could be, as
>John Sheperd said, "pinned down to a single day". Wouldn't this
>depend on the brightness of the star and the viewing conditions and
>God knows what?
Yes it depends on the brightness and the observers latitude. But as Art
says it is reproducible for a given star provided the observing conditions
are good. It was probably used by many peoples over the years including
Native Americans. The 1 degree difference per day translates into 4 minutes
longer visibility per day. This is long enough to know if you missed the
heliacal rising by a day.
Cheers,
John
