Aspen Technology on Tuesday announced 2FQ11 results showing that its transition from a perpetual to subscription model continues to gain momentum. AspenTech’s total revenue of $50 million up 17% over last year, including a 983% (no typo: 983%) increase in subscription revenue, from $1.2 million last year to nearly $12 million in 2FQ11.

The details:
• AspenTech’s total revenue of $49.8 million increased 17% from $42.7 million in the second quarter of the prior year.

• Subscription revenue was $11.8 million, up from $1.2 million a year ago.

• Software revenue, which includes term-based and perpetual licenses, was $13.5 million in the second quarter of fiscal 2011, up from $9 million in the year ago period.

• Professional services, maintenance and other revenue was $24.5 million, down from $32.5 million a year ago.

• All of this led the company to report a loss from operations of $9.3 million and a net loss of $10.3 million for the quarter ended December 31, 2010.

• AspenTech closed 24 bookings valued at over $1 million during the second quarter, up from 18 a year ago, and 54 bookings between $250,000 and $1 million, compared to 57 in the second quarter of fiscal 2010.

• The average deal size for bookings over $100,000 was roughly $653,000 in the second quarter, down from about $778,000 in the second quarter of fiscal 2010.

These trends become more visible when we compare the first six months of fiscal 2010 and fiscal 2011. Subscription revenue jumped from $1.2 million to $21.5 million, non-subscription software revenue from $20 million to nearly $23 million — or a doubling of total software revenue to $44.3 million. As a result, AspenTech believes it is “well positioned to achieve [its] full year goal of upper single digit to double digit growth for the full year.”