Yerkes Observatory - Explore Scientific Demo Days: We had some crappy weather the first couple of days - a cloudy and rainy Friday, a nice sunny Saturday but a cloudy Saturday night. Sunday was nice after a brief shower BUT Sunday night was extra special being able to look through our scopes on the lawn of the famous Yerkes Observatory. I'd guess we had over 200 people stop by over the weekend and say hi and talk with us about our instruments. Some came as far away as Iowa to see us. We made some new friends and had a great time.