Hi, Bianchi's in Celeste are nice. Sorry I can't help you but I thought I'd reply anyway.
It it was a racing bike frame I would suggest measuring the width of the bottom bracket. If it was Italian it would have an Italian bottom bracket of 70mm width. Japanese frame were built with British threaded bottom brackets which measure 68mm wide.
There is a website that does have copies of some Bike Catalogues. the website is:
http://bulgier.net/pics/bike/Catalogs/
You might be lucky and find a Bianchi catalogue from the late 80's - your bike may be illustrated there.