No. The N900 would need a compass for that. It can be "done" via a number of logical workarounds, including using the GPS and making the user walk in the direction they are facing until the direction is determined, or forcing teh user to initialize and reinitialize which direction is north. Neither of these workarounds would promote a positive user experience.
Have an initialization process: the soft shows you first a bright star or object (the moon...), you point it to the object and press a button to initialize. Just as it is done on computer-controlled scopes (except than only one star is needed). And be blessed that there is no compass, that is the biggest source of errors in the skyscout.