Carnival Cruise Line's 1900-passenger Celebration was recently christened in Miami, and is now sailing seven-day cruises to San Juan, St. Thomas and St. Maarten.

The new vessel completes Carnival's 20-month, three-ship expansion, increasing the line's annual capacity by one-quarter million passengers, according to Mickey Arinson, president of the line.

Carnival reportedly is projecting 525,000 passengers in 1987, and 550,000 in 1988.