What is the difference between Auto/partial correlation

I have attached a file that displays both the autocorrelation and partial correlation of two time series of 1500 seconds with 3000 points each. The original time series measures the change in area of a shape over time. I calculated both correlations with a lag of 60 points. I would like to know if 1: If I have chosen a lag value that is too large, and 2: What do both these graphs represent.

I am assuming that the autocorrelation displayed reveals that areas displayed with a lag of 30seconds (i.e. 60 points) aren't as well related to points closer to the initial time point.