We present the photometry and theoretical models for a Galactic bulge microlensing event OGLE-2000-BUL-43 .
The event is very bright with I = 13.54 mag , and has a very long time scale , t _ { E } = 156 days .
The long time scale and its light curve deviation from the standard shape strongly suggest that it may be affected by the parallax effect .
We show that OGLE-2000-BUL-43 is the first discovered microlensing event , in which the parallax distortion is observed over a period of 2 years .
Difference Image Analysis ( DIA ) using the PSF matching algorithm of Alard & Lupton enabled photometry accurate to 0.5 % .
All photometry obtained with DIA is available electronically .
Our analysis indicates that the viewing condition from a location near Jupiter will be optimal and can lead to magnifications \sim 50 around January 31 , 2001 .
These features offer a great promise for resolving the source ( a K giant ) and breaking the degeneracy between the lens parameters including the mass of the lens , if the event is observed with the imaging camera on the Cassini space probe .