This was really simple to put together. I started with a rectangle of black felt (190cm x 45cm) and loads of felt remnant's and fat quarters - it cost me less than £10 to buy the black felt and the additional fat quarters I needed.
I started by drawing & cutting 2 circles for each planet from felt and 1 circle from wadding - sizes were: Mercury 2.5cm, Venus 4cm, Earth 4.5cm, moon 1.5cm, mars 2.5cm, Jupiter 21cm, Saturn 16cm, Uranus 14cm, Neptune 13cm - I made these measurements up as I was eyeballing a photo in a Montessori book to judge the sizes, I personally think the Moon, Neptune and Uranus ended up too big but I wasn't about to start all over - it does what I intended by giving them an idea of the relative sizes so if you want to change any of the dimensions feel free : )
I sewed the planets together and then glued embellishments to them (was bored of sewing by this time LOL)
Next I moved onto the Sun - again I eyeballed the picture and tried to create the edge of a circle to show them its immense size in relation to everything else. I stitched the wadding and yellow felt directly to the black felt.
I was going to use velcro dots to mark the positions of the planets but managed to misplace them, It turned out the girls had a general idea of positioning already so they weren't essential.
They did decide however, that the asteroid belt was essential so I gave them some scissors, glue, felt bits and a black arch of felt. They worked for ages so I didn't have the heart to tell them that their asteroids were too big (some are bigger than the moon!) and in reality they are small rocks and dust.
The name labels are handwritten and laminated, I store all the planets and labels in a plastic wallet (so I can easily add other information cards at a later stage) and rolled up the mat.
Would I have done anything differently - yes I would have used double the black felt and folded in half with some wadding in between so it made a nice padded base and would probably have sewn a pocket on the back for the planets etc, but that's in a dream world where I have more time to make things :)