Updated from 7:21 a.m. ESTApple ( AAPL) says the calendar is partly to blame for earnings guidance that left Wall Street underwhelmed Thursday. The company reported a record December quarter late Wednesday, saying earnings rose 92% from a year ago on better-than-expected sales. But Apple also issued earnings guidance that was well short of estimates, sending the stock down $1.49, or 1.8%, to $81 in early Thursday trading. A number of factors contributed to that near-term outlook, CFO Peter Oppenheimer said on a conference call, including an expected seasonal decline in sales of the company's iPod digital music players. Oppenheimer also noted that the company's new Intel ( INTC)-based notebook computer won't ship until next month, and that the current second quarter will have one fewer week than the holiday period. Still, Oppenheimer stressed that the company expects its current period to be the second-best quarter in its history, trailing only its just-completed one. "We remain very enthusiastic about our product pipeline," he said. "We are confident about our strategy." Setting aside its outlook, the company had a lot to cheer about from the holiday period. In its quarter ended Dec. 31, Apple earned $565 million, or 65 cents a share. That was up from the year-ago period, in which the company earned $295 million, or 35 cents a share. Sales jumped 65% year over year to $5.75 billion. Excluding options costs, the iPod maker would have earned $595 million, or 68 cents a share. On this basis, analysts had predicted the company would earn 61 cents a share in the quarter, according to Thomson First Call. The company predicted in October that it would earn 46 cents a share, or 49 cents a share excluding stock options costs.