As well as the sunshine and the cold (which plays hell with the telescopes) there are other factors. The only thing to look at in the summer is the sun, as it is up pretty much all day. So you could look at this.From the north pole you are looking at the sun (for a solar observation) through the thickest possibl chunk of atmosphere, leading to a lousy picture. add to this the fact that at the north pole there is nothing stable to stick your telesscope on, as it is a frozen ocean not solid ground, and it all becomes a bit of a waste of time.