Sun declination

[Makis]

@koying
Please answer he following. I fully understand the azimuth and elevation concept. You will have to understand though that there is a case where azimuth at 143 for example and elevation of 70 it doesn’t bother (in May in Greece) and azimuth 143 and elevation of 29 it does bother. (October)

If you agree with the above, continue reading. If you don’t there is no further discussion

Please tell me how you would get the following automation to work. In every case the problem here has to do with the implementation of the automation.

If you have time also please tell me how you would solve this problem. what automation you would suggest

@Makis

So
In October the cover should close at azimuth 144 and elevation of 29. In May the cover should close at azimuth 173 and elevation 71. Lets assume that these points are the min and max numbers for azimuth and elevation.

How can I adapt these numbers in the below part of the automation?

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entity_id: sun.sun
          # window left
          above: 143
          # window right
          #below: ???
          value_template: "{{ float(states.sun.sun.attributes.azimuth) }}"
        - condition: numeric_state
          entity_id: sun.sun
          # window bottom
          above: 29
          # window top
          #below: ???
          value_template: "{{ float(states.sun.sun.attributes.elevation) }}"

[DavidFW1960 (David)]

@Makis

azimuth at 143 for example and elevation of 70 it doesn’t bother (in May in Greece) and azimuth 143 and elevation of 29 it does bother. (October)

I would contend that at ANY time of the year az 143 and elev 29 would bother and elev 70 wouldn’t. The elevation and azimuth of the sun define the bothersome position and the date has nothing to do with it. So you need to define the troublesome az/el combinations and they will cause the same problem every day of the year when the sun is in that position

[koying (Chris B)]

You have to find out the minimal and maximal values for both azimuth and elevation where the sun is bothersome.

You know 143 Az and 29 El is bothersome.

so you already know minA < 143 < maxA
you also know minE < 29 < maxE < 70

You just have to find the exact values of minA (window right), maxA (window left), minE (window bottom), maxE (window top) for you case.

[Joerg]

@koying

You have to find out the minimal and maximal values for both azimuth and elevation where the sun is bothersome.
You know 143 Az and 29 El is bothersome.
so you already know minA < 143 < maxA

minA is 143 and minE 29 in October
minA is 173 and minE 70 in May

[Joerg]

@DavidFW1960

So you need to define the troublesome az/el combinations and they will cause the same problem every day of the year when the sun is in that position

Nope. Its not as I showed above. It starts bothering him at A143/E29 in October and A173/E70 in May. At least that what he said again and again.

ps
and in May it is not bothering him at A143 where the elevation is at 166

[DavidFW1960 (David)]

You didn’t show anything. It’s only the position of the sun that is relevant and that’s defined only by the elevation and azimuth… unless you are claiming that 145/29 is a problem in oct but that same 145/29 isn’t a problem in may but that would be impossible because the sun at any given az/el is either a problem or it isn’t any time of the year

[Joerg]

@DavidFW1960

defined only by the elevation and azimuth

at a certain time… even when we don’t use it at a trigger maybe.
It starts bothering him in October at A143/E29 - in May the azimuth is 82 when at E29.

[sjee]

Using azimuth and elevation, time and date are irrelevant.

[Joerg]

Of course he can use A143/E29 in May as he might need in October, but the sun will not be bothersome for him until the sun reaches the azimuth of 173 and an elevation of 70.
At his location there is no A143/E29 combination in May… in May the elevation is 66° when the sun reaches A143.
And as you can see, its about date/time because we have to describe his problem using dates.

[Makis]

@Joerg

Of course he can use A143/E29 in May as he might need in October, but the sun will not be bothersome for him until the sun reaches the azimuth of 173 and an elevation of 70.
At his location there is no A143/E29 combination in May… in May the elevation is 66° when the sun reaches A143.

seems that they can not understand that no matter how I say it or how many time I say it.
No point of further discussion for me

[Joerg]

He can’t use A173/E70 in October because aside that it starts bother him at A143, there is no combination of it. In October at A173 suns elevation is 37°
In other words: some has to find the A and E at a given date/time. This is what his calculation is doing.

[finity]

@koying

geometry speaking a point has no dimension

Relative to the size of the universe the sun has no dimensions.

Relative to the size of the earth the sun is really big.

so to us it’s a really big point of light.

Maybe a real world example might help…

I used to work in the nuclear power field.

we needed to learn how to model radioactive sources to calculate radiation doses at certain distances away. we used the assumption that the radiation sources were “point sources” so could use the inverse square law to calculate the dosages.

in geometry a point may be dimensionless, but in the real world points have dimensions. the sun acts as a point source because it shines in every direction at once.

we aren’t talking about theoretical physics. this is the real world.

@DavidFW1960

I would contend that at ANY time of the year az 143 and elev 29 would bother

@DavidFW1960

the date has nothing to do with it.

But…I’m pretty sure there will only ever be one day of the year when the sun is at that combination of coordinates. That’s why the date has an impact on the calculation. but the date of those coordinates will be different depending on your latitude.

Again if the sun acted like a laser light and came straight in thru the window at a 90 angle of incidence to the window then I agree it would be an easy calculation and the rectangular model would work.

But since the sun is a point source and produces a sphere of light, for a south facing window, the angle of incidence on that window in the morning and evening would be almost 0 degrees in the horizontal axis (and increasing/decreasing thru the day) and would be from about 0 degrees to 90 degrees (depending on latitude) in the vertical axis.

So the arc cut by the sunlight in the room will be different throughout the year.

It’s not a simple rectangle.

[sjee]

@Joerg

In other words: some has to find the A and E at a given date/time

No, as @koying wrote he needs to find the min/max for both elevation and azimuth to specify a range.

[Joerg]

@DavidFW1960

unless you are claiming that 145/29 is a problem in oct but that same 145/29 isn’t a problem in may

This is exactly what he claimed and I showed in the model above.
The sun hits his window in May when at A173/E70 - but this was mentioned again anda again and again…

[DavidFW1960 (David)]

@finity

But…I’m pretty sure there will only ever be one day of the year when the sun is at that combination of coordinates.

You’re likely right about that but it’s still useful to define the bounds of a figure that can be used in an automation. If the az>x and el<y then etc…

[DavidFW1960 (David)]

@Joerg

This is exactly what he claimed and I showed in the model above.

I’m sorry but that is BS

[sjee]

@Joerg

This is exactly what he claimed and I showed in the model above.

No you didn’t. Your model doesn’t even include elevation

[Joerg]

Nope. In May / Summer the sun stands so high, that it didn’t hit his window before noon.
In October the sun is so low 29°, that it went straight through his window at A143°

[Joerg]

No why is this not?

[Joerg]

Okay, I see, I cutted it to much.
Here’s the full model: