* When does winter start astronomically? This depends on the hemisphere. In the Northern Hemisphere, winter starts on the winter solstice, around December 21st. In the Southern Hemisphere, it starts around June 21st.

* When are the best constellations to see in the winter? This depends on your location, but some popular constellations to see in the Northern Hemisphere winter sky include Orion, Taurus, Gemini, and Ursa Major.

* Are you asking about a specific winter star event? There are many, such as the Geminid meteor shower in December, or the peak of visibility for certain constellations.

Please clarify what you mean by "winter stars" so I can give you a more accurate answer!