Relative to the errors in estimating distance:
I have observed six Space Shuttle launches from my community, Albany, GA, USA which is about 350 miles from the flight path as the Solid Rocket Boosters were completing their burn. If I had not known better I would have said they were ten or fifteen miles away and the flickering flames were a thousand feet long. In reality, they subtended about three degrees of arc, which made them close to 20 miles long.