Elevation and Observations

[sderamus]

Does anyone have a table or formula one can use to calculate the effect of one's elevation above sea level on observing stars? I recall seeing something once upon a time showing how much of an increase in magnitude one gets the higher one goes. But then I recently read that the atmospheric effect is minimal until one gets up above like 50,000 feet or something.

The reason I ask is that I have a choice of observing sites - one is at sea level, but fairly isolated from light pollution. The other is on top of a mountain approximately 3,400 feet above sea level, but there are towns in the valley that add to light pollution (it is green on the North American Light Pollution Map for those of you familiar with that). Which would be a better observing site?

Thanks!

Sterling

 

[Chronos]

The loss due to atmospheric absorption is less of an issue than light pollution.