I just purchased this book for the coming school year. In the Intro it tells you that the lessons are in-depth and should be broken up depending on your child’s age and attention span.
There are 14 lessons which can be divided into 2-week segments. Read the text and do notebook assignments the first week; work on activities and projects the second week.
According to the Apologia Astronomy book if you do science 2 or 3 days a week, you can read 4-6 pages a day to finish a lesson and begin the activities. This gives you 28 weeks for the entire book…allowing for vacations or emergencies…and lessons 2 & 13 will probably take longer than 2 weeks because they contain more info.
On another note, this book looks really interesting and I’m excited to start reading it with my kids. 🙂