Long line of sight

[Scott P]

Last night I found out something interesting. I have been working a lot of hours so all my hikes have either been just after sunset or at night. Last night I hiked up Dome BM which is located NE of the Douglas Pass and NW of Grand Junction. It’s elevation is 9039 and it’s a rather obscure peak that doesn’t stand out much (other than perhaps the man made dome near top-whatever it is).
Although I have been to the same place 19 times, the sunset lighting was such that I noticed something that I hadn’t noticed before. The sky was very clear with little or no haze and when I looked to the SW I got a surprise. I could clearly make out the shapes of Mount Hillers and Mount Pennell in the Henry Mountains of Utah. The shapes of those mountains are unmistakable to me since I have seen them countless times over the decades. This was impressive to me so I took a photograph and decided to calculate the sight distance when I got home. Mount Hillers is near Bullfrog Utah and on the east side of Lake Powell so I knew that it was a long way. Could it contend with the other record site distances that have been photographed in the United States?

For the curious, here’s how the numbers panned out and some of them have to do with a 14er in Colorado.

The longest site distance photographed in the United States is Denali to Mount Sanford with a distance of 223 miles.

In the Lower 48, the record belongs to Mount Rainier to Mount Brunswick (Canada) with 195 miles, followed closely by Mount Whitney to Mount San Gorgonio Mountain with 190 miles.
Next on the list is Uncompahgre Peak (Colorado 14er) to Mount Ellen Utah and Mount Hillers to Navajo Mountain, both at 183 miles.

After doing the calcs, Dome BM to Mount Hillers is 159 miles, but was not enough to contend with any of the above. Still, Dome BM is an obscure 9er that doesn’t stand out so 159 miles is still impressive. There may be a longer line of sight distances on some of the other neighbors to Dome BM.

Here's the photograph. It was taken with my cell phone so isn’t the best (it was clearer in person), but it does show that you can photograph Mt. Hillers and Mt. Pennell from Dome BM in Colorado, something, I never would have suspected.

20221006_190438 - Copy.jpg (55.96 KiB) Viewed 1716 times

[HikerGuy]

However, there is one situation in which objects can be made out at great distances: when they are silhouetted against a bright background, such as the setting Sun, or (just after sunset) a bright twilit sky.

Without resorting to an artificial light source, there's the example of mountains in Corsica, seen repeatedly from Genoa, Italy, at a distance of over 260 km. The best visibility was just before sunrise and just after sunset, when the distant peaks were silhouetted against the bright twilit sky: the lower atmosphere was in the Earth's shadow, while the upper troposphere was still lit by direct sunlight. These observations were extensively discussed by Maraldi four centuries ago.

https://aty.sdsu.edu/explain/atmos_refr/horizon.html

[Scott P]

https://aty.sdsu.edu/explain/atmos_refr/horizon.html

Thanks for the link. It's quite interesting.

[jibler]

yeah i eat this stuff up

I was doing home calculations at home after hikes on what I thought I saw in the distance and comparing that to maps - for several years!

but then people here clued me into peakfinder and caltopo's viewshed thing and it was all ruined a little - even if it is much easier now to have all those calculations done for you.

[lukePlumley]

This is a fun topic. I’ve noticed Ellen several times from the peaks near Douglas Pass and De Beque. I’ve always wondered if there is line of sight to Ellen from the peaks near Dinosaur (Zenobia) or Flaming Gorge (Pine Mtn. Wy) since you are looking straight down the Green River Valley. Plenty of high ground in the way though so you would need just the right line.

[Scott P]

This is a fun topic. I’ve noticed Ellen several times from the peaks near Douglas Pass and De Beque. .

Nice. Do you remember which peaks near De Beque? If you can see Mount Ellen, you might be able to see Hillers as well. Either way De Beque to Ellen would be a really long line of sight.

[lukePlumley]

I mention it in this trip report. These are from Corcoran Wash. I haven’t been to Shale BM yet but that high ridge might have a line north of the La Sals.

[Scott P]

I mention it in this trip report. These are from Corcoran Wash. I haven’t been to Shale BM yet but that high ridge might have a line north of the La Sals.

Nice. I'll have to check it out

[ChrisinAZ]

South Sister to Rainier is 190 miles or so--was lucky enough to get to see that several years back.

The farthest line of sight from Elbert is East Spanish Peak, I want to say 145 miles. Also saw that on a crystal clear winter day...

[Scott P]

OK, here's one for you. I took this photo before work and it is the max zoom off my cellphone looking from the summit of Dome BM (looking slightly south of east). This is from the same Peak at the beginning of the thread that you can see Mt. Hillers and Pennell from.

I'll figure it out when I get home tonight, but wanted to see if someone here could figure it out before that. I haven't noticed this one before since it didn't stand out until it was covered in snow.

What mountain is this? (I'm thinking Sopris, but not sure).

20221031_135203.jpg (43.92 KiB) Viewed 396 times

[docjohn]

My sense is this a picture of Sopris, west summit. Note the biggish cirque.

[Scott P]

My sense is this a picture of Sopris, west summit. Note the biggish cirque.

That's what I'm thinking too. It pretty cool (at least to me) that you can see Sopris, Mt. Hillers (on the west side of Lake Powell), and all the way to Explorer Peak in the western part of the High Uintas Wilderness from the same lowly 9er.