Ealiest Comet Halley Sighting

[astroron (Ron)]

This article suggests that Comet Halley could have been seen by the Greeks a couple of Hundred years earlier than the Chinese observations
http://www.bbc.co.uk/news/science-environment-11255168

[renormalised (Carl)]

If they can get back this far (466BC), with some careful calculations and a bit of luck, they should be able to go back further. They just need to look in those records which have been kept and see if anything coincides.

Very interesting

[CraigS]

Until that article, I thought big, close comet orbits (like Halley's) were fairly predictable.

It's tough going back that far in time. It's not like an eclipse, which is really predictable

I learn something new every day.

Thanks, Ron !

Cheers

[renormalised (Carl)]

You have all the possible gravitational perturbations to take into account in the comet's orbit, over time. Makes for some hairy calculations!!!. You can never pin the orbit down with any certainty.

[Outbackmanyep]

Not just gravitational perturbations, you also have non-gravitational perturbations which contribute to a comet's orbital prediction.
It is quite fascinating to dig in the past to find these writings, you'll be quite surprised to know that the Chinese and Arabs kept very good documents relating to celestial events, although i'm not sure what the Australian aboriginals made of comets and i am curious to know!