Is there a closing time and if what is it? I am interested in star gazing and looking for a spot to do that.

Try going out to hopkins middle very few lights all country and not from Columbia

By City statute, unless otherwise posted, public parks close at sunset or 9 PM, whichever is earlier. However, people tend to come and go in that park throughout the night and unless something "less than savory" draws the attention of law enforcement, they generally leave the park-goers alone.

I think it's at dusk but they have lights down there but they do close at night for safety

Can anyone recommend a place within a radius of say 25-40m in Columbia or Irmo where less lights are found and good for stargazing?

There are too many lights at the park for effectively watching the stars. If find somewhere a little more secluded and away from downtown...