Hi Sharon
There are lots of Spanish inland areas where you may be able to find a property that is remote but would probably not have mains water and electricity - easy enough to live with that!
I have a little fishing house in the middle of Tarragona on the river Ebro, this is a beatifull area, very sparsley inhabited and property is ver cheap.
Driving around the country roads I see lots of old houses, little traffic on the roads and very few lights at night.
Whilst fishing at night we try not to use torches in order to preserve our night vision and, even without a moon, there is enough light from the stars, if the sky is clear, to walk around without falling in the river

The shooting stars are amazing - something the "townies" miss out on.
Don't forget what I said about being careful over the legality of rural houses.
A friend of mine bought an old building in the town (Riba Roja d'Ebre) to convert in 6 apartments and, along with the package, was a plot of 45,000 M2 about 2 Klms from the town. It is planted with old almond & olive trees and it is not worth his while to harvest the crop because he has a business down here in Costa Blanca as well.
Something like this might be perfect for you. Buy the land, start harvesting the crop and earn a few bob. Get permission to build a store on it (your observatory as well) and put in "camping" cooking and folding beds for your night sessions - and live happily ever after!

The land is just right for you because there is a high hill between there and the town which blocks all the light.
Buy one of Brian's flats in the town, which he will renovate to your requirements, for when you want to return to the civilised world.
You'll get the whole lot for well under 100,000 as long as you don't go crackers with the apartment refurbishment.
Being 2 Klms outside of town, it will be a long, long time before the town spreads its PGOU out that far but, you never know, you could eventually be sitting on some vary valuable building land.
I must apologise about all that - I just can't control my estate agent instincts!

However, something like that in a rural area could be the ideal solution for you.
If you want to discuss the idea further, I have to say (as a forum moderator) that it would not be appropriate for us to discuss this on the public forum - so send me a Private Message!
I bet my fellow moderators are going to give me hell for that one!
Homefinder