Ashtanga was developed by Sri K. Pattabhi Jois. It is a vinyasa form of yoga that follows a set sequence of asanas. As with vinyasa you move from one asana to another using a single breath. This makes ashtanga a very powerful and strong practice.
There are 6 sequences in an Ashtanga flow: Primary, Intermediate and four Advanced Series. Each of the sequences start with sun Salutations 5 of Surya Namaskara A and 5 of Surya Namaskara B followed by a standing sequence. They all end with the same final sequence with the middle sequence begin different for each of the series.
Even though a typical class moves quite quickly, most Ashtanga studios offer Mysore-style classes, which allow students to work at their own pace and to be assessed by senior instructors.