Longest line of sight (UK)

Dai Corner

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Dunno, but there will be a whole load of Tory MP's queuing to jump off the cliff-edge :E
And a load of Labour MPs watching them while rehearsing their soundbites for the election campaign,as well as SNP MSPs rehearsing theirs for the next independence referendum!

Apologies for going off topic. Back to the subject.
 
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Howardh

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I think it can see from Beachy Head from Worthing, perhaps 25 to 30 miles away. Please can somebody confirm this.
27 miles. Yes I would think so, especially as you can see the Great Orme from 40+ miles standing at sea level. May be able to see Beachy Head from Bognor, 40 miles away.
 

Howardh

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That would depend on atmospheric conditions, or on being somewhat above sea level.
With normal atmospheric conditions, I calculate that a height of 160 metres should be visible from about 34 miles away.
https://en.wikipedia.org/wiki/Horizon#Effect_of_atmospheric_refraction
Sea level is a difficult concept when dealing with line of sight. If you were genuinelly at sea level (ie a fish popping his head out of the water) you'd see next-to-nothing! Mean sea level - as in the OS maps, is (I believe) the point between low and high tides, so standing on the shore at high tide could mean your head is a good 5m above MSL and you will see a lot further! add to that the chances are a viewer (as I was at Lytham) will be on a promenade above the beach, so add another 2 - 5m so in old money you already have a 25-30' start!!
Those few metres could make an enormous difference, I have no idea of the formula used (help!!) but I'd love to do if from MSL, high tide level and promenade level.
 

tony_mac

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I have no idea of the formula used (help!!) but I'd love to do if from MSL, high tide level and promenade level.
Taking the height you are viewing from, and the target height you are viewing to, both in metres, then you can get the maximum visible distance, in km, with
3.86 * (square root of viewing height + square root of target height).
That's just an approximation, given 'normal' atmospheric conditions, but it should be reasonably accurate.

I guess if you are viewing over water, then whatever height the current tide is should be the measure - as that's roughly how high the sea between the two will be.
 

Howardh

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Taking the height you are viewing from, and the target height you are viewing to, both in metres, then you can get the maximum visible distance, in km, with
3.86 * (square root of viewing height + square root of target height).
That's just an approximation, given 'normal' atmospheric conditions, but it should be reasonably accurate.

I guess if you are viewing over water, then whatever height the current tide is should be the measure - as that's roughly how high the sea between the two will be.
Nice one. So if you are 20' (6m) above high tide level you should be able to see beyond 45 miles on a clear day and see a hill of only 250' (c70m) high, as indeed my photo of the Great Orme shows.
The only fly in the ointment is "Lancashire" and "clear day".
 

tony_mac

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Nice one. So if you are 20' (6m) above high tide level you should be able to see beyond 45 miles on a clear day and see a hill of only 250' (c70m) high, as indeed my photo of the Great Orme shows.
That's not what I get - if Great Orme is 200m high, the top would normally only be visible (from 6m height) for about 40 miles (64km). For a 70m hill, it would only be 26 miles.
 

Teflon Lettuce

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Sorry if this is off topic, but all this debate about line of sight has sparked a memory of something I was told by a teacher at school... He said that if you stood at the Ivinghoe Beacon viewing point and looked east there was nothing higher until you reached the Urals in Russia... my question is though how high would you actually have to be to actually see the Urals from Ivinghoe Beacon?

ps Ivinghoe Beacon is on the Beds/ Bucks border between Dunstable and Tring
 

cuccir

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Interesting thread.

I grew up in Barrow-in-Furness, and there's some very extensive views in the right locations. On a really clear day - once or twice a year - it's possible to see some land well to the west of Blackpool Tower, which I've always presumed was the Great Orme though my Dad has always reckoned it's more likely to be the hills of Snowdonia (on a tangent, our TVs always picked up S4C by default rather than channel 4 which is what convinced us it must be Wales) - anyone got any ideas which it would be? From the south coast of Walney Island it's possible to see the Isle of Man, Wales, the hills of Lancashire, Yorkshire, and of course the Lake District. That must be one of the most extensive views from sea level!
 

tony_mac

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anyone got any ideas which it would be?
Snowdonia. Great Orme isn't nearly high enough to be seen from there. It's 200m high and 60 miles away, but Foel-fras, for example, is 70 miles away, in almost exactly the same direction, but over 900m high.

my question is though how high would you actually have to be to actually see the Urals from Ivinghoe Beacon?
Pretty much in space! (i.e., something like 50 miles up)
 

Groningen

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On a dutch physicssite there is a formula of: (horizon in km * horizon in km) / 0,0784 = height in meters.

Whether is is true?! I do not know.

Our Dutch Wikipedia gives height in meters, there square root it * 3,57 kilometers. So 100 meters in height becomes 10 * 3,57 = 35,7 kilometers to the horizon, but it also depends where you stand on the earth.
 

Howardh

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Reckon that's the BT tower south of macclesfield taken from Matchmoor Lane Bolton - a tad over 1000'. Can anyone confirm - not very clear on a zoom lens!!
 

route101

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Reckon that's the BT tower south of macclesfield taken from Matchmoor Lane Bolton - a tad over 1000'. Can anyone confirm - not very clear on a zoom lens!!
Looks like the M60 in Centre of Pic , crane top right at Manchester Airport ?
 

Howardh

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M60, yes, although the fact that traffic isn't standing could confuse! Many Airport, 99% yes, needs conformation. It's the crane on the far right if the photo is expanded. On very clear days you can planes approaching to land with binoculars.
 

Altrincham

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Reckon that's the BT tower south of macclesfield taken from Matchmoor Lane Bolton - a tad over 1000'. Can anyone confirm - not very clear on a zoom lens!!
Fabulous photo. Definitely the mast at Bosley, south of Macclesfield. The big building left of centre with the sloping roof is the ski slope at the Trafford Centre. The low-lying ridge seen centre-right, behind the airport buildings and the crane, is Alderley Edge.
 

route101

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I was on the WCML north of London and compared to where i stay in Scotland , you do get good views in that part of England where you see quite far .
 

Foggy Dewhirst

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Oh yes, can only be as there's nothing else in the way. My main issue was - was the lump at the end either of the Orme's and if so, which one? Looking at maps and that landscape view then I would bet it's the Great Orme, now I'd like a photo taken from there towards the Fylde coast to see how far beyond one can see - as it's higher up than I was! A quick search turns up the Isle of Man from the Great Orme, impressive!
https://llandudnopictures.files.wordpress.com/2010/11/isle-of-man-from-the-great-orme.jpg
I remember years ago looking at Blackpool Tower from the Great Orme, through binoculars. I also picked out both Cathedrals in Liverpool.
 

175mph

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When traveling up the A1077 on the 350 bus out of Scunthorpe, on a clear day just before getting to Winterton, the Humber Bridge can be clearly seen.
 

Bald Rick

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I remember years ago looking at Blackpool Tower from the Great Orme, through binoculars. I also picked out both Cathedrals in Liverpool.
You can see the Great Orme quite clearly from St Anne’s on Sea, just south of Blackpool (on a clear day). You can also see the mountains of Snowdonia behind, which is a good deal further.
 

tony_mac

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You can see the Great Orme quite clearly from St Anne’s on Sea, just south of Blackpool (on a clear day). You can also see the mountains of Snowdonia behind, which is a good deal further.
A couple of people have said that - but I'm not sure it's accurate. It's not particularly big, so you shouldn't be able to see it at all from 40+ miles away (unless there are weird atmospheric conditions, or the earth is flat).

5 miles further on, in very nearly the same direction, there are much bigger hills that you would be able to see (e.g., Moelfre Uchaf)

btw - this site looks interesting...
https://peakvisor.com/panorama.html...191&alt=12&yaw=-136.76&pitch=-1.27&hfov=60.00
 

Bald Rick

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A couple of people have said that - but I'm not sure it's accurate. It's not particularly big, so you shouldn't be able to see it at all from 40+ miles away (unless there are weird atmospheric conditions, or the earth is flat).

5 miles further on, in very nearly the same direction, there are much bigger hills that you would be able to see (e.g., Moelfre Uchaf)

btw - this site looks interesting...
https://peakvisor.com/panorama.html...191&alt=12&yaw=-136.76&pitch=-1.27&hfov=60.00
Oh it’s definitely true, because I’ve seen it with my own eyes. One thing to my advantage is that I’m observing from a 4th floor sea front flat.
 

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