Applied Astrophysics for gardeners.

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Applied Astrophysics for gardeners.

Postby kingofnobbys » Wed Aug 07, 2019 7:47 am

So now my neighbor tells me he wants to replace the fence ( that he wrecked when he removed the original garage and slab ) . I'd already done these calculations to check my offsets from the N boundary fence and they made me change the orientation of my 3 grow beds and determined the 400mm height for the beds in the first place - this wasn't a number I plucked out the air on a whim.

I can't move my beds without incurring a LOT of expense and heavy equipment ( to pull the posts and 0.3m D x 0.7m deep concrete out of the ground - this IS NOT GOING TO HAPPEN ) , so he's going to have to keep the new fence the same height as the existing fence else I'll loose some growing area.

So some astrophysics has been applied , calcutating the sun's altitude at 9am, noon and 3pm through an entire year , resulted in the following graph :
Image
I have a program that calculates this kind of information ( one my hobbies is astrophysics / cosmology ).

And some trig calcutations to work out max acceptable fence height that allows my entire 3m beds to be in full sun
Image

Nothing hard in these calculations , I've not used 3D spherical trig to work out the exact view factors at 9am or 3pm , so these are very conservative estimates of solar altitude.

A screen shot of the spreadsheet I used to automate the calcs
Image

So : I'll be suggesting they either fix the fence ( that they damaged when they demolished their old garage and pulled up/ broke up their old slab with a big machine ) , or if they MUST replace it, I will only agree TO A NEW FENCE IF IT'S NO TALLER THAN 1.7m from MY GROUND LEVEL. Else no deal., and I want 3 written quotes.

My preference is a fence height not higher than tan(38 deg) + 0.4 (bed height) + 0.2 (fill depth)
= 0.78m + 0.6m = 1.38m ==> 1.4m MAX.


Of cause if he insists on a fence taller than say 1.7m ( based on my ground level not his ), I can add another course of 200mm x 75mm sleepers to the 3 grow beds to raise the grow zones by 200mm to compensate somewhat , will cost maybe $100 per bed to this (carpentry and timber + 1 cu-m soil extra ( $80 each ) + labor ( a day's work ) , but I wont be telling him this ). I guess I'd be billing him for this cost.
CBDs: Cleopatra & Caesar born 28Jan19.
Puff (RIP 10Dec15),Rex (RIP 16Mar17),Toothless (RIP 26Nov17).Peppa (RIP 22Mar19).
EBTSs : George & Mildred (born july 2010).
EWSs : Fluffy - 4yr rescued lawnmowing accident victim 14Nov17.
Lucky - cat attack rescue, fatal SI RIP 21Jul2010.
Wriggles - rescued injured ,thought she was a big lizard, over 8 yrs old, RIP 2Feb16. .
Gecko : Godzilla the hatchling GEHYRA GECKO (hatched May 2019)
kingofnobbys
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Re: Applied Astrophysics for gardeners.

Postby AHBD » Fri Aug 09, 2019 7:32 pm

I don't understand all the diagrams but that would be pretty frustrating to have your garden beds planned out and then get a wrench thrown in to your plans by your neighbor.
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Re: Applied Astrophysics for gardeners.

Postby kingofnobbys » Sat Aug 10, 2019 3:45 am

This is why I am getting my own quotes :
1) I don't trust these people ( who will very likely try to con me into letting them built it themselves and go halves on costs , they will try to rip me off for dodgey fence build )
2) I want to have control over how this fence is built and it's quality
3) if the fence must be replaced I want it done properly and I don't want to ever have to revisit this at a later date

Turns out the fence will be 27m long = 12m x 1.8m H near house and 15m x 1.4m H from back fence to my old level slab ( this is very close to same height as the old fence that these people have ruined ).
I wont be negotiating on this.
CBDs: Cleopatra & Caesar born 28Jan19.
Puff (RIP 10Dec15),Rex (RIP 16Mar17),Toothless (RIP 26Nov17).Peppa (RIP 22Mar19).
EBTSs : George & Mildred (born july 2010).
EWSs : Fluffy - 4yr rescued lawnmowing accident victim 14Nov17.
Lucky - cat attack rescue, fatal SI RIP 21Jul2010.
Wriggles - rescued injured ,thought she was a big lizard, over 8 yrs old, RIP 2Feb16. .
Gecko : Godzilla the hatchling GEHYRA GECKO (hatched May 2019)
kingofnobbys
BD.org Sicko
 
Posts: 10570
Joined: Tue May 12, 2015 10:56 pm
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