Can you see Vancouver BC from the top of Rainier?

I saw Mt. Hood from Hermiston, Oregon once. Don't know how far that is, but I thought it was pretty cool. Where are you getting as the crow flies distances? A good web-site?

I saw Mt. Hood from Hermiston, Oregon once. Don't know how far that is, but I thought it was pretty cool. Where are you getting as the crow flies distances? A good web-site?

<br><br>There are probably several sources... Topo! software, maybe topozone. I use GoogleEarth and the measure tool:<br><br> earth.google.com/

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Sky, interesting topic, and one that I've long been fond of. It's funny that I calculated a table almost identical to yours about 4 years ago. I also wrote a Distance Calculator to the Cascade Volcanoes a couple of years ago, so maybe I should update it to include view distances from each peak (and maybe even peak-to-peak). Thanks for the idea.<br><br>

We could even subtract 15% for refraction and easily get this one.  We don't need no stinking mirage!<br>

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Light travels ever-so-slightly slower in the denser air, which makes its trajectory bend toward the surface of the earth when looking down from a summit. So in reality all the distances should be a little shorter, by about 15%.

<br><br>But I'm not sure why you think that refraction makes sight distances shorter. It's well known that under normal atmospheric conditions, refraction INCREASES the distance at which you can see a mountain (i.e. increases its elevation angle). It's the same reason that one can see the sun a few minutes before it rises above and after it drops below the horizon. The bending of light rays allows one to see beyond the curvature of the earth, it doesn't make the light rays drop down sooner and thus reduce the viewing distance. The "15%" effect of refraction actually increases the viewing distance by about 7.5% given the square-root dependence of height on viewing distance [since sqrt(1.15) - 1 = 0.075 = 7.5%]. For example, Rainier's 147 mile viewing distance actually increases to about 158 miles.<br><br>The links given by Ruxpercnd above provide useful details about this. <br><br>Edited to add: Here's another webpage with nice diagrams .<br><br>

so, what does this have to do with the price of beans in Wisconsin?

It's about time Amar set me straight. <br><br>It's clear that the light ray gets bent toward the normal in the denser air near the surface. I mistakenly thought refraction would decrease the distance because I thought about the initial tangent line getting deflected and hitting the surface sooner. I failed to consider that because of refraction, one can look along a line that would never touch the horizon without the atmosphere's effects, which will get bent to touch the surface over the horizon. Thus refraction EXTENDS the distance on can see. <br><br>So now Sam's observation seems more than reasonable on an ordinary clear day. <br><br>I have to go 180 degrees and say YES, you can see Vancouver from the summit of Mt Rainier.<br><br>I've enjoyed this immensely. Thanks for all the great links, everyone. And now I know why the day is longer than 12 hours on the equinox!<br><br>In the spirit of covering my tracks, I've corrected my misconceptions about refraction on the webpage I made. Here's my nifty new diagram to illustrate how refraction extends the geometric estimate:<br>