I really enjoy using the resource Stellarium, mainly because once it is downloaded you don’t need the internet. It is amazing that this resource can show a realistic sky in 3D, just like what you might see with the naked eye or a telescope. In our school we may an iPad trolley so the children can use the iPad for their own exploration of Stellarium. I have the Stellarium app on my interactive whiteboard, allowing me quick access without internet issues.
Another online resource that I hope to use in September is Astronomy Picture of the Day (APOD). This online tool can be used with infants and a colleague used it every day last year as a warmup activity. On APOD, you can show a bring and encourage children to make observations for a few minutes. This can lead nicely to a whole class discussion or pair discussion. I have heard the language can be tricky for younger students so I would change the language to suit the children’s abilities.