Paramount Pictures / 20th Century Fox

Film director James Cameron talks with Leonardo DiCaprio and Kate Winslet during the shooting of a crucial post-sinking scene in "Titanic." The newly released 3-D version of the film will show the sky as it actually appeared that night, thanks to astronomer Neil deGrasse Tyson's goading.

Astrophysicist Neil deGrasse Tyson doesn't mind that "Titanic" film director James Cameron called him a "son of a bitch" for shaming him into correcting the movie's constellations.

"I take it as a frustrated expression of affection," Tyson, director of New York's Hayden Planetarium, told me today. "As in, 'you son of a bitch, you got me there.'"

Thanks to Tyson's persistence, moviegoers who go to "Titanic" in 3-D will see a truer representation of the night sky when Rose (played by Kate Winslet) looks up into the heavens after the ship sinks. "That sky, I would say, was the most important sky in the movie," Tyson said. And in the original 1997 version of the film, it was wrong.

In a widely quoted interview with the British magazine Culture, Cameron said the sky scene was the only shot he fixed for this year's 3-D re-release:

"It's because Neil deGrasse Tyson, who is one of the U.S.' leading astronomers, sent me quite a snarky email saying that, at that time of year, in that position in the Atlantic in 1912, when Rose is lying on the piece of driftwood and staring up at the stars, that is not the star field she would have seen, and with my reputation as a perfectionist, I should have known that and I should have put the right star field in.

"So I said, 'All right, you son of a b**ch, send me the right stars for the exact time, 4:20 a.m. on April 15, 1912, and I'll put it in the movie.' So that's the one shot that has been changed."

The basic problem was that a space-savvy observer would see that the sky in the original version of the movie was unrecognizable, and in fact was produced by mirroring made-up stars on the left and right halves of the screen. Tyson saw that as a needlessly sloppy move, and he made that opinion known to Cameron and his team in a succession of letters, emails and personal encounters. He wrote about the "Titanic" trip-up and other Hollywood missteps in his 2007 book, "Death by Black Hole." You can watch him tell the tale about "Titanic" and other sci-fi movies in this video clip:

When Cameron's people finally asked Tyson to provide a better sky, the astrophysicist used a standard planetarium program to generate the star field for the proper latitude and time of night, captured a high-resolution image and sent it off to the filmmakers.

"The Big Dipper came out nicely," Tyson said.

The sky was initially fixed in the bonus materials for a special DVD version of "Titanic" a few years ago. "I took that as a triumph and let it be," Tyson told me. Now the corrected sky appears in the big-screen version of the film itself, thanks to post-production wizardry.

Tyson said he can understand why it took a big re-release for Cameron to change the sky. "As a director, you don't want to have to rethink all that, and I respect that," he said. Tyson said his respect for Cameron has grown even more now that the right stars will be on display in theaters around the world.

Will Cameron put the space-savvy S.O.B.'s name in the credits for the 3-D movie? Tyson says he doesn't know, and really doesn't care.

"If he does, that's fine," Tyson told me. "I'm a servant of the public interest and the public's appetite for information about the universe. I get these calls all the time. ... The mere fact that an artist cares about getting the science right, and thereby transmitting that science literacy to the consumers of that art — that's enough reward for me."

More about 'Titanic' and Neil deGrasse Tyson

• 10 reasons for the Titanic tragedy
• James Cameron refloats 'Titanic' in 3-D
• Tyson on NASA's need for a budget boost
• From black holes to black history

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Noel Vasquez / Getty Images

Ashton Kutcher, seen here at a Los Angeles Lakers basketball game in February, is the 500th customer to sign up for a Virgin Galactic suborbital spaceflight.

Virgin Galactic says uber-celebrity Ashton Kutcher is the company's 500th customer to sign up for a suborbital trip into outer space.

"I gave Ashton a quick call to congratulate and welcome him," Virgin Galactic's billionaire founder, Richard Branson, said today in a blog post announcing that Kutcher was coming on board. "He is as thrilled as we are at the prospect of being among the first to cross the final frontier (and back!) with us and to experience the magic of space for himself."

Kutcher, who got his start in television on "That '70s Show" and is now one of the stars of the highly rated sitcom "Two and a Half Men," is said to have a net worth of around $140 million. So the $200,000 fare for a ride on Virgin Galactic's SpaceShipTwo rocket plane, also known as the VSS Enterprise, shouldn't break the bank. He's as well-known for his online presence (with 9.8 million Twitter followers) and his gossip-column appeal (due to last year's breakup with Demi Moore) as he is for his filmography.

All this makes him arguably the highest-profile prospective spaceflier confirmed to be on Virgin Galactic's list — although Tom Hanks, Katy Perry, Brad Pitt and Angelina Jolie are reportedly on the list as well. Beyonce and Jay-Z are among other celebs considering a flight. The stars are reportedly all paying their own way, except for physicist Stephen Hawking, who is receiving a free ride courtesy of Branson.

For Stephen Attenborough, Virgin Galactic's commercial director, getting to the 500-passenger point is as big a milestone as getting Ashton Kutcher to sign on. "It's great to get to No. 500," he told me.

It's way too early to put Kutcher's flight on the calendar. SpaceShipTwo is still in the midst of free-glide flight tests, with rocket-powered test flights expected to begin this year. Last year, Branson said he was holding out hope that he and members of his family will be able to take a ride into space as this year's Christmas present. That suggests 2013 could mark the start of commercial service, although Virgin Galactic and its partners at California-based Scaled Composites say the schedule is totally dependent on the outcome of tests at the Mojave Air and Space Port.

The current plan calls for commercial flight operations to be based at Spaceport America in New Mexico. SpaceShipTwo, which is capable of carrying six passengers and two pilots, would be linked up to its wide-winged WhiteKnightTwo carrier airplane and brought up to an altitude of 50,000 feet. At that height, SpaceShipTwo would drop from its mothership and turn on its hybrid rocket engine. The blast would take the craft beyond 62 miles (100 kilometers), the internationally accepted boundary of outer space — a commanding height from which Kutcher and his fellow passengers could see the arc of planet Earth and the dark sky of space above.

There'd be a few minutes of weightlessness, and then the passengers would return to their seats for the descent. After weathering up to 6 G's of acceleration, the fliers would glide down to the landing — and get their astronaut wings back at Spaceport America.

Attenborough said Virgin Galactic is already giving a lot of thought to determining who would fly when. One of the factors in the formula would give priority to customers "roughly in the order that they signed up," he said, but the schedulers also would consider customer preferences and the possibility of achieving firsts in spaceflight (for example, ahem, first prime-time TV star in space). "We're expecting to be able to keep everyone happy," Attenborough told me. 

How long do you think it'll be before Kutcher is clicking his camera on the final frontier? And do you suppose there'll be a deal to document everything for reality TV? Feel free to weigh in with your comments below.

More about celebrity spaceflight:

• Fly Justin Bieber into space, scientist says
• Bunnies in jetpacks? It's Playboy Club in space!
• Director James Cameron targets spaceflight
• Celebrities in space?

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.