[Solanum]

I have twin girls that are 5 next week and in prep. I find that they are quite interested in astronomy but the biggest difficulty in using the scope is their inability to close one eye and effectively look through the other. So I'd suggest taking an eye patch for each scope and getting them to were those (can add a fun pirate twist as well).

They are much better with binoculars, so if you can get hold of some big binos they would be a worthwhile addition to your evening (bearing in mind the smaller inter-pupilary distance they have of course!). These are especially good for the terminator of the moon as they can see the 'mountains' there.

I agree that the solar system scale is a great idea. I think my girls struggle with scale concepts, but they are very interested in the positioning of the planets and know that the inner ones are hot and the outer ones cold etc. So some basic info like that would be useful.

Finally, as a father of a five-year old yourself I'm sure that you are aware that they will be tired! My kids go to bed at 7:30-8:00, so much later than that and they can get a little fractious....