Does anybody know if I can go in October? Like the first 2 weeks for stargazing?

Take a winter coat it gets cold

Yes, it's open year round. The website has lots of information https://www.dcnr.pa.gov/StateParks/FindAPark/CherrySpringsStatePark/Pages/default.aspx

I believe the park is open all year. It is an open field

Take a winter coat

Should I take any heater for camping? Or the jackets are sufficient?. I am planning for first week of October