Lengthening days, but by how much?

  • Hey Guest, We've had to cancel our 2020 Summer BushMoot PLEASE LOOK HERE for more information.

Broch

Full Member
Jan 18, 2009
3,189
2,356
Mid Wales
But graphically it is a Gauss curve?
Not strictly speaking; a gaussian distribution curve doesn't repeat and trends to zero whereas circular motion is never ending and the equation is cyclic.

But, for an x axis only covering 2 Pi it looks the same I'll grant you :)
 
  • Like
Reactions: Janne

Janne

Guest
Feb 10, 2016
12,368
2,257
Grand Cayman, Norway, Sweden
Oh dear living out there is so hard.pool too cool? Try mine.. it's frozen over tonight. Bracing! Oh wait... it's a large puddle, best I can do though. :):D. I'd love a pool but I do have a river within a ten minute walk.
River is nicer. Has fish in it.
All we get are night frogs drowning in the pool overnight.

The ones that croak so loudly you wake up if it rains during the night.
After a rain, they like to mate and lay the eggs.

With the sun shade the pool gets up to 29C in summer, 31 C without. Wintertime it drops down to 27C without the sun shade.
 

Woody girl

Full Member
Mar 31, 2018
2,622
1,744
61
Exmoor
Yes the river is great in the summer. It's full of kids throwing stones and dogs swimming after sticks thrown by their owners barking fit to bust . But pop up or downstream a bit and it's blissfully quiet. This time of year it's canoe heaven. Quite a challenge in places.
 

Woody girl

Full Member
Mar 31, 2018
2,622
1,744
61
Exmoor
Can't wait for spring to show it's nose though. Wild garlic and other goodies to gather and eat. Lighter evenings and the banishment of the dreaded S A D. Arthritic bones ease up and my gypsy feet start to itch!
 

Robson Valley

Full Member
Nov 24, 2014
8,298
1,391
McBride, BC
Don't forget the tilt of the earth. The sun sweeps from 23.5S to 23.5N over the course of a year.
So we all see the solar path change a lot.
Then, I have zig-zag mountain ranges within 5 miles of my house, both to the east and the west.
As a result, calculated sunrise and sunset values are useless to me. with 7,000 - 9,000' shadows.
Just count on the skylines cutting an extra 30-60 minutes of shine off both ends of every day.
December 21, my house is in shade at 1:52 PM because of the west ridge.
 
Jan 13, 2018
358
249
63
Rural Lincolnshire
Then, I have zig-zag mountain ranges within 5 miles of my house, both to the east and the west.
.
Now there is the big difference between us :
I went for a short 5.3 mile walk on New Years Day, and living in the 'flat lands' I took oxygen with me as I knew I'd be going up our local mountain (known as a mole-hill in other places)

My start & finish height above se-level was 29 foot and the highest point on the walk was 55ft ASL, I had a total height ascent (all of the 'ups' added together) of 49 feet.

My ears 'go pop' if I go upstairs on a Bus.

 

Billy-o

Native
Apr 19, 2018
1,129
435
Canada
I buy an Almanac each year. Tells me everything about hightides and dawns and sunsets and when to plant my carrots, which Holy Day to remember when I do that and odd things to note about the stars this year. Plus any number of anecdotes about the countryside and flat out, entertaining lies about, well, pretty much all subjects ... apart from time and tide.
 

Robson Valley

Full Member
Nov 24, 2014
8,298
1,391
McBride, BC
A whopping 49' huh? Too funny. Must block off a whole lot of sunshine!


Google McBride, BC and take a look.
I can say only that it's like Jasper National Park without the crowds or the prices.
Highest locals are north up the Renshaw. Mr Robson is an hour east @ 12,900+'
My zig-zag local horizons totally foul up any sense of fine changes in day length.

Get on the TransCanada highway #1 in Kamloops, BC and drive thru the Rockies, thru Banff, and out to Calgary, AB.
If you ironed that highway out flat, there are so many ups and downs that those 2 cities would be 13 miles further apart.
 
  • Like
Reactions: Alan De Enfield

Robson Valley

Full Member
Nov 24, 2014
8,298
1,391
McBride, BC
My altimeter is broken. I have no idea how far up we go for bird hunting. Alpine for ptarmigan and Dusky Grouse for certain.
When you get a glimpse of the Fraser River through the forest, it is one very, very long way DOWN

Your sunrise is sun down here. First the peaks light up rose gold.
Half a big cup of coffee later, the mountain sides light up and eventually there's sun in my east study windows.

Then my house goes into shadow in the evening but the east range stays lit up for hours.
Until only the snow caps are sunlit!
End of June, I can still read the newspaper at 10PM with no extra light.

Long days and short days is as good as it gets here.
 

Sundowner

Full Member
Jan 21, 2013
875
337
66
Northumberland
The actual change follows a sinusoidal curve - so there is virtually no change in December then maximum change around the 21st March (I believe 2.8 minutes?) then no change again in late June. If you plot a sinusoidal curve with daylight hours against day of the year for wherever you are in the world it is reasonably straight forward to work out a) how many daylight hours there are in a particular day and, b), (by calculating the gradient) the rate of change of daylight hours on a day - :)
The actual change follows a sinusoidal curve - so there is virtually no change in December then maximum change around the 21st March (I believe 2.8 minutes?) then no change again in late June. If you plot a sinusoidal curve with daylight hours against day of the year for wherever you are in the world it is reasonably straight forward to work out a) how many daylight hours there are in a particular day and, b), (by calculating the gradient) the rate of change of daylight hours on a day - :)
Didn't know, but, you seem to do quite a bit of plotting
 

Chainsaw

Native
Jul 23, 2007
1,311
77
53
Central Scotland
Alan, get a job or is this your job? Or have you got too much time on your hands?
heh heh.... It's part of my job, I have meetings with folks from all over so I need to know their timezone. There is a handy wee international meeting planner on there which I use quite a lot.
 

Robson Valley

Full Member
Nov 24, 2014
8,298
1,391
McBride, BC
I have several clocks which display north polar projections and a ring of notable cities around the perimeter.
Local time and UTC and silly squeeking alarm functions!
Of course all the continents are distorted to hello. I don't care at all.

I used to be an active ham operator (VE7APC) but the finals are cold (Yaesu FT901DM).
The clocks were and are wonderful to see the days and nights circle the globe.
 
  • Like
Reactions: santaman2000
Jan 13, 2018
358
249
63
Rural Lincolnshire
I have several clocks which display north polar projections and a ring of notable cities around the perimeter.
Local time and UTC and silly squeeking alarm functions!
Of course all the continents are distorted to hello. I don't care at all.

I used to be an active ham operator (VE7APC) but the finals are cold (Yaesu FT901DM).
The clocks were and are wonderful to see the days and nights circle the globe.
I too was active (a long time ago - late 60's) G3LCR
I went over to the 'dark side' on 27Mhz SSB and enjoyed voice DX all over the world from my mobile with a Ham Major 588 with super low 26Mhz added, 5Kc shift and a 6 foot Moonraker mag-mount.
 

Robson Valley

Full Member
Nov 24, 2014
8,298
1,391
McBride, BC
My clocks all show a moving ring of 12 hrs white and 12 hrs black for a bit of a sense of day/nights.
Good enough to know who's up and who should be snoozing, but never to the minute.

Japanese ham radio operators never, ever sleep. On 24/7.
Best voice QSO was with a UK ham. We must have chatted for an hour or more.
 
  • Like
Reactions: Alan De Enfield

santaman2000

M.A.B (Mad About Bushcraft)
Jan 15, 2011
16,411
883
63
Florida
I buy an Almanac each year. Tells me everything about hightides and dawns and sunsets and when to plant my carrots, which Holy Day to remember when I do that and odd things to note about the stars this year. Plus any number of anecdotes about the countryside and flat out, entertaining lies about, well, pretty much all subjects ... apart from time and tide.
Yeah; I like The Old farmer's Almanac.
 
  • Like
Reactions: Robson Valley