MountainViews
Welcome to MountainViews
If you want to use the website often please enrol (quick and free) at top right.

General Whatever you want to say that doesn't fit under the comments about places or another forum.
Sort by >

More controls

<< Prev page 1 .. 189 190 191 192 193 194 .. 391 Next page >>
Post details Post   (Contract pics)
Hello Simon,My nam.. by simon3   (Show all posts)
THIS SATURDAY AUGU.. by Bleck Cra   (Show all posts)
I'm speaking at a .. by ahendroff   (Show all posts)
Interesting accoun.. by khkk   (Show all posts)
Mountain Rescue Te.. by simon3   (Show all posts)
Thought I'd post s.. by paulca   (Show all posts)
found the explanat.. by jackill   (Show all posts)
Can give no assist.. by Conor74   (Show all posts)
simon3
2011-08-16 13:17:29
"Laser Beam" from simon3 Contract pics
Picture: Laser Beam (Contract pics)

Lasers in the mist
On the top of Stumpa Dúloigh jackill did his usual thing of assessing where the highest point actually is. MountainViewers have tended to use the Abney Level as a way of assessing this. In this case the highest point appears to be some metres from the junction of two fences. jackill was assessing the distance from this junction to the highest point where I was with the camera. He has a handy little laser rangefinder gadget for this which showed the fence junction to be 21m from the highest point.

The laser light shows up nicely, being scattered by the misty air. Shows up that is except when it was getting near to the camera - something that begs explanation. As anyone knows who takes photos in the Irish mountains, mistiness is a huge issue. In this case the mistiness is Mie scattering caused by water droplets. These are rather large compared to the scattering caused by small particles that causes blue skies (Rayleigh scattering). Mie scattering also has another important quality. Most of the scattered light goes forward close to the original line of travel. So when viewing the droplets in the beam from a distance you see them because you and they are nearly in line. However, nearer, the angle is different and you can't see the beam.

It's all beautifully explained here:
http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html

And the relevance? Well knowing about the two types of mist and what, if anything, you can do about them is really useful for upland photographers. For example, because of forward Mie scatter the sun or the moon tend to get a whitish halo around them when there are large particles in the air. The same doesn't happen for Rayleigh scattering - you don't see a blue halo around the sun. This laser beam is a great example of the physics.
Can anyone explain.. by Dessie1   (Show all posts)


RECENT CONTRIBUTIONS 1 2 3 .. 22 Next page >>
Summit Comment
Ben Dash: One of my earlier attempts
TommyV 4 days ago.
Ben Dash was one of my earlier attempts at hill bagging, back in the days when I had no gps and didn't believe I needed a map. I went through some bog that people had bagged turf on before I found...

  
Summit Comment
Slieve Foye: Not bad.
shanks a day ago.
Excellent if introduceing new walkers reasonably well signed but was a little overgrown in spots and path really close to wire fencing at others. Apart from that ☺

  
Summit Comment
Knockardakin: Bag it as part of the cliff walk
TommyV 4 days ago.
I technically haven't bagged the summit of this hill as it wasn't listed on MV when I did the Ciiffs of Moher walk, but it would be a very small detour to bag it. I was no more than 50 meters from...

Summit Comment
Clifden Hill: Didn't bag it
TommyV 4 days ago.
I drove as far as the point mentioned by Jamessheerin. Nice views over Lough Inchiquin, the drive trhough the trees only add about ten mentres of elevation and lots of briars so I got back in my c...

  
Track
Wicklow Coastal Walk
Onzy 2 days ago.
Route from Pennycomequick Bridge to Brittas Bay.Not to be taken lightly - the stretch around Mizen Head is blocked by fi walk, Len: 9.2km, Climb: 104m, Area: Dublin/Wicklow (Ireland)

  
Track
La Gomera- Unfinished Business - GR132
GSheehy 3 days ago.
Maybe the height gain above is correct. Maybe it just felt like one of the hardest things you?ve done. Maybe the cumul walk, Len: 56.3km, Climb: 3018m, Area: Spain, Canary Islands ()

Summit Comment
Cloontohil: My nearest MV hill
TommyV 4 days ago.
This hill is only a few kilometers over the road from my home house. However without Mountain Views website you would scarcely know it's a hill as it is situated in an area of high ground anyway s...

  
Summit Comment
Knocknalarabana: A quick drive.
TommyV 4 days ago.
More of a drive than a hike. Well worth it for the views.

  
Track
Pouy de Hourmigué
David-Guenot a week ago.
walk, Len: 17.9km, Climb: 1379m, Area: France, Occitanie ()

Summit Comment
Devilsbit Mountain: Get a bit of the Devil in ya!
TommyV 3 weeks ago.
After a day of bagging some of the more unremarkable summits in North Tipperary, Devilsbit was a delight. There is designated parking at S06115 73178. Follow the waymarked path all the way to the ...

  
Track
The Laugavegur (Hot Springs) Trail, Iceland
mcrtchly 2 weeks ago.
Listed as one of the top twenty best treks in the world by National Geographic, the Laugavegur Trail (The Hot Spring Rou walk, Len: 56.6km, Climb: 1414m, Area: Iceland, South ()

  
Summit Comment
Cooneen Hill: Very average
TommyV 3 weeks ago.
Nothing to add to simon3's directions. Like quite a few of the hills in North Tipperary, this one is through a Coilte forest track to begin with and then the tough push through some horrible groun...


RECENT CONTRIBUTIONS 1 2 3 .. 22 Next page >>