Re: Grand Canyon Web Cam

TOOOO COOOOL!!!

So now I can peek at both my haunts (Yosemite/Grand Canyon) when I am supposed to be working...!

B

Working? Like anybody still has a job these days?

I haven't fired myself yet(self employed)....but.....I AM starting a third career as a bill collector...

B

Bee wrote:

> I AM
> starting a third career as a bill collector...

Just heard a story today about outsourcing collections to India.

The web cam earlier (when the sun was up) said "visibility 223 miles"

Is that possible from the rim? I thought it was pretty good to stand on Lassen and see Mount Rose from over 100 miles away, I hear from Mount Rose on a nice day you can see Mount Shasta, and I guess on a good day from Mount Whitney you can see approaching 200 miles to a peak in central Nevada. But those are peak to peak. What about 223 at Grand Canyon? I'd like to see that! (looking at stars doesn't count)

Vince wrote:

> The web cam earlier (when the sun was up) said "visibility 223
> miles" Is that possible from the rim?



I would guess that it rather depends on what one has been smoking.

From a purely geometrical viewpoint and ignoring any topographic variation between an observer and an object 223 miles distant (i.e., the objects at both locations are on the surface of a sphere; alternatively speaking, both are at the same elevation), one would need a mountain to be ~27.5k feet high in order to be seen. Since the South Rim is around 7k elevation, our mountain 223 miles distant would have to be 34.5k high in order to be visible. (Almost assuredly, we would have noticed this mountain.)

Allowing for reasonable over-the-geometric–horizon refraction (notably the 20% estimated correction factor to the radius of the earth stated in the first link below), one would need an elevation differential of ~22.5k to see a mountain 223 miles distant; this would make our mountain elevation 29.5k to be visible from the South Rim. (Hmmm, still higher than Everest.)
http://en.wikipedia.org/wiki/Horizon
https://www.msu.edu/~ashton/research/pubs/aag_08_viewshed.pdf

The “Distance of the Horizon” calculator in the following link is useful if you don’t want to bother doing the calculations by hand. [Note: this calculator does not apply any refraction correction; either multiply the calculated distance by 1.10 = √1.20 or add 10% to the calculated distance to obtain the refraction-corrected estimate.]
http://www.nga.mil/portal/site/maritime/?epi_menuItemID=eb404b8cc4b240c21b2079106327a759&epi_menuID=0feacf38cf96a8b21b2079106327a759&epi_baseMenuID=e106a3b5e50edce1fec24fd73927a759

If you want to amuse yourself, you can use the calculator to convince yourself that if you were standing on a mountain at the 7k elevation of the South Rim, you would only need the peak at 223 miles to be either ~6.7k high in order to be visible (no refraction) or ~4.5k (refraction-corrected).

I suspect that the Visual Range number quoted in the webcam link is estimated from instrumentation similar to that described here:
http://phoenixvis.net/instrumentation.html
[Lacking all the high tech. equipment, one should be able to arrive at a similar number by measuring the relative intensity of a couple landmarks, provided one knows the distances to them, their relative or absolute albedos, and they are being equally illuminated (equal sunlight or cloud cover). Hey! Photoshop may be useful for something after all.]

Yes, this is how I’ve spent my Sunday afternoon. It’s raining here (Silverado, CA) too and this is my way of avoiding doing any useful work.



Post Edited (02-08-09 16:55)

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THE YOSEMITE POST
Voice of the Rocky Marmot Empire

Vince,

Go get your truck stuck again. You need to get some fresh air.

Jim

eeek:>>Just heard a story today about outsourcing collections to India.<<

I like the personal touch; it keeps the recidivism down to a low roar.

B

Bee,

The two sectors still hiring are the health field and the US Government. There are jobs available as US Revenue Officers collecting taxes. Go for it, Bee.

Jim

Vince: >>I hear from Mount Rose on a nice day you can see Mount Shasta,<<

Sometimes in late winter, there are times when you get atmospheric conditions that magnify the horizon, so you can see Lassen or Shasta from the Northern Sierra foothills. As far as 200 mi vis at Grand Canyon, the best chance of that is after a cold winter storm when the chaser winds blow everything out.

B

tomdisco>>The two sectors still hiring are the health field and the US Government. There are jobs available as US Revenue Officers collecting taxes. Go for it, Bee.<<

So funny -- my best buddy is a retired assistant to the Chief Counsel of the IRS Tax Court, and he was the one who trained me in collections technique!! He said that my record is better than any of his agents (Im at 95% -- I have this one outstanding account that I collected 2/3 yesterday, and I am promised the balance 3/1. I have not even had to use my last ditch line "You KNOW I served in the IDF...!!"

B

Looks like the storm in California finally made it to Grand Canyon.

I cant tell, is that snow in the lower left corner of the image, or is it just the surface color?
B

Bee wrote:

> I cant tell, is that snow in the lower left corner of the
> image, or is it just the surface color?

It's a structure of some type. It was there before the storm hit.

Cool, fresh snow in the canyon this morning.

Looks SO beautiful!

Thanks for adding this little perk to the form

B

Thanks for the above analysis, I figured visibility of 223 miles is a physical impossibility, especially taking into consideration the length of Grand Canyon is 277 miles. Even if you looked west and saw a certain distance, then looked east and saw something, and added them together, you probably couldn't see more than a 50-mile panorama at best.

I notice today (2/10, 10:43 a.m.) the visibility suddenly has dropped to 28 miles. That makes much more sense.

The Grand Canyon has always had that problem of the purplish haze from pollution. It probably comes from a variety of places, but supposedly one source is winds blowing in from Southern California. I've heard claims that they might get three days a year where you might find postcard-perfect conditions for air clarity.

When I used to hike in the East Bay, one of my favorite destinations was Mission Peak (a great place to view raptors and Hang Gliders)

after a winter storm the north winds would blow out all of the smog, etc, you could see the Sierra, Lassen, and Shasta from the 3,000+- peak. (On a rare occasion, you can see Shasta from highway 5 in the Sacramento area)

B