Spending a warm summer night under the stars can be one of the most enjoyable, relaxing experiences around for anyone, serious astronomer or not. Unfortunately, the weather is not always conducive to comfortable astronomy, often the exact opposite in the case. As any astronomer who has gone through a full year of observing can say, there's nothing colder than a clear winter night. Herein arises the question: how to keep warm?
The bad part about astronomy is that it is a stationary hobby so, without any movement to build up body heat, you can get cold really quick. As a general rule, seasoned astronomers will always tell a newcomer to dress (or at least have handy) clothing that will suffice if it were actually 10 degrees colder than the forecast low for the night. Bottom line, if it's going to get down to 50 tonight, dress as though it were going to be 40. Another tip: layer up. When layering, your body heat will warm up the air between the layers of clothing, providing for some very effective insulation. As hard as it may be to believe, layering three lightweight coats can actually be as warm as (or warmer) than a single winter coat. Try it and see.