We observe Bose-Einstein condensation (BEG) in a dilute atomic gas coo
led below 280 nK. Rb-87 atoms are optically trapped and pre-cooled, lo
aded into a magnetic trap, and then evaporatively cooled through the B
EC phase transition. We present results of quantitative studies of con
densate fraction, interaction strength, and excitations of the condens
ate in this system.