(Adds details on presentation)
CUPERTINO, Calif., Sept 12 (Reuters) - Apple Inc Chief Executive Tim Cook took the stage at the Steve Jobs Auditorium on the new Apple campus on Tuesday for the company's biggest product launch in years, which was expected to include a completely redesigned top-of-the-line iPhone.
Cook opened the event, where the company is also expected to roll out two other new phones, an upgrade to the Apple Watch and a higher-definition Apple TV, with a tribute Jobs, who died in 2011.
The Apple building itself was considered to be Jobs' final product, and Cook spent a few minutes boasting about the design, energy-saving features and public spaces at the new campus, including a flagship Apple Store.
The theater, never before open to the public, features an expansive glass-enclosed lobby, with two massive white stone staircases leading down to the auditorium. Inside, the decor is similar to that of Apple's stores, with hard maple flooring and tan leather seats.
The new products and the holiday shopping season that follows are the most important for Apple in years.
The company has sold more than 1.2 billion iPhones over the past decade and ushered in the era of mobile computing, but last year had a substantial decline in revenue as many consumers rejected the iPhone 7 as being too similar to the iPhone 6.
Apple hopes the new high-end phone, expected to be called the iPhone X, will silence critics who say the company has lost its innovation edge.
The phone features an edge-to-edge display with richer colors and facial recognition to unlock the device without a fingerprint reader or physical home button.
The two other models, expected to be called the iPhone 8 and iPhone 8 Plus, update the iPhone 7 and iPhone 7 Plus. They could also include new features, such as a glass back similar to the iPhone 4 that would facilitate wireless charging.
The phones will likely boast a steep price tag. Bernstein analyst Toni Sacconaghi predicts the top-end model will cost $899, though other analysts expect it to top $1,000. That compares to a top base price of $769 for the iPhone 7 Plus.
Much of that added cost is driven by more expensive parts, like a higher-resolution display, 3D sensors and more memory capacity.
"Some of these components are just darned expensive. There's just no doubt about that," said Brian Blau, Apple analyst at Gartner.
Blau expects Apple to keep several lower-priced models in its lineup.
Shares of Apple, which had been trading slightly lower before the event kicked off, reversed course and were last up 0.15 percent.
Analysts expect the company to reveal an Apple TV that operates at higher resolution than its previous set.
The higher resolution could play into video programming efforts, which have shifted into a higher gear recently with two high-profile executives hired away from Sony Pictures Television.
The company is also expected to reveal more details about the HomePod, its voice-activated home speaker that competes with Amazon.com Inc's Echo devices and the Google Home speaker.
Apple announced the HomePod in June and said it will ship in December.
Lastly, Apple is expected to announce a new version of the Apple Watch. Previous versions had to be tethered to a user's phone in order to send or receive data, but the new version is expected to connect to wireless data networks.
Apple does not say how many Apple Watches it sells. Gene Munster, an analyst with Loup Ventures, believes sales of the watch could double or even triple because of the new connectivity.
But even a huge boom in one product and topping smart watch rivals include Fitbit Inc and Garmin will not move Apple's financials much, since the iPhone accounted for 63 percent of the company's $215 billion in sales last year.
"It's a really big deal for the wearables category for Apple, but it's not a big deal for the company," Munster said. (Reporting by Stephen Nellis; Editing by Jonathan Weber, Mary Milliken and Meredith Mazzilli)