Although we missed Castle Geyser the night before, I was aiming to see it in the morning. Castle Geyser erupts roughly every 14 hours. Based on the prediction time from the night before, I knew it would be erupting some time in the early morning. I didn't want to miss it so got up when it was still dark to wait it out (and also try for some full moon shoots). I had no idea when Old Faithful was supposed to go off and as luck would have it, just as I walked by it erupted. Good timing, but also a little unfortunate as I didn't have any of my camera gear out. I had some focus issues and missed the actual eruption, but caught some of the steam afterwards. It was pretty cool (and a little eerie) to be the sole visitor watching Old Faithful erupt in the early morning. I'm so glad we were staying nearby!