Hi DJDD,
The big one is the Tainai Star Party but I am not sure when it will be held
in 2009. See
http://www.tainai.jp/tainai/indexe.html
This is undoubtedly one of the two you had heard of.
I believe it is typically held in August, so that won't be much use to you.
The National Astronomical Observatory of Japan offers public viewing nights
every month. See
http://www.nao.ac.jp/E/MTK/StarGazing/index.html
With some luck, you might be able to hook-up with some forum members in Japan
that can organize an observing session for you.
Some of our customers observe from part way up Mt. Fuji from time to time
which would be a wonderful setting.
You might want to drop a line to Barry Gooley at Kokusai Kohki down in Kyoto.
See
http://www.kkohki.com/English/visitKokusaiKohki.html
Barry speaks English. If you have been to Japan before, you have undoubtedly
had the opportunity to visit beautiful Kyoto, otherwise it is a 'must-see' destination
when visiting Japan. Only a few hours on the shinkansen from Tokyo.
Be sure to pick up your Japan Rail (JR) pass before you depart from Australia to
make significant savings.
Best Regards
Gary Kopff
Mt. Kuring-Gai