Sun declination

Configuration
102

Oh and another point to illustrate…

(Sorry, not meaning to pick on you David) but I think there won’t be a 145/29 combination in May.

for any given coordinates there will only be one (maybe two?) days a year that the combination exists.

the sun track in the sky isn’t a freely varying thing.

it’s constrained completely by the geometry/tilt of the earth and orbital mechanics.

I think also if the tilt of the earth was 0 degrees it would be easier. but since we have a tilt of 23.5 degrees it makes it even more complicated.

103

The real world is 3D (4D?). In the real world, what you call “a point” is a sphere.
Sure, you can use any words for anything, but words, specifically in Mathematics, represent very specific notions.

In your example, you assumed a point for your radioactive source to simplify calculations, fair enough, but that doesn’t make the margin of error induced by the assumption magically disappear :wink:

104

Exactly.

Have you ever read “Horton hears a Who” by Dr. Seuss?

He said it best…“a sphere is a point no matter how small” or big. :slightly_smiling_face:

If it makes it easier for you to accept then feel free to replace “sphere that acts like a point” anywhere I say “point”. It ends up with the same concept either way.

105

Yes, but this just shows on one specific moment in time. As mentioned, you need to specify a range, min/max of both azimuth an elevation to cover a whole year. Once you’ve done that time and date become irrelevant.

If a certain combination of azimuth and elevation never happens it will not be bothersome.

106

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107

With all due respect, my science references would rather be Stephen Hawking than Dr. Seuss :smiley:

A sphere (or circle in 2D) dimensions DO matter, geometry speaking

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108

I actually recorded the sun path at his location for May 20th and October 25 with the app I pointed to above.
→ October
→ May

Of course the simulation is not 100% correct but close to what I believe is happening at Makis house.

ps
note the offset related to north I had to put the house to. In October the sun appears when it went around the corner of the house, while in May/summer it appears in the windows when it went “over” the roof to the frontside of the house.

1 Like
109

this is BS as @DavidFW1960 said. He knows better

110

I see what you mean, in May the window is basically in the shadow of the building untill 12:30.

111

Yes, something like that. The sun is pretty high in the morning already so it has to crawl over the roof to the frontside and at 12:30h or at A173° or at E70° at that day, it shines in his window.
Next day at 12:30h + some minutes or at A173,32° or at E70° and some minutes.

112

Well, I couldn’t believe it myself until I used the simulation. If some like me is at N51° or more northerly and has an normal window and open view it might be easy. I just need to use an azimuth range between 130 and 260 degrees and I don’t care if this is 100% correct.
The others are somehow correct with the azimuth/elevation combination. But such a combination also is date/time related.
What you IMO need if using an azimuth range, is a calculation, when the sun is NOT shining in the window. With other words: calculate the date/time or azimuth/elevation when the sun is crawling over the roof (from when to when will this be?) until it shines to the frontside and don’t close the covers while it does. :wink:

113

Thanks for the all the effort Joerg. I will keep the automation as it is. I just proposed my sensor for someone that is near me and the usually automation wouldn’t work or would be time consumed to track every month where the sunlight becomes bothersome. If someone alter the factor 0.31 in my sensor to his measurements he just needs 2 different points and it will work with no other observations etc. I think (but I am not sure) it will work even at N51° (probably the factor should be something like 0.05)

1 Like
114

Yes, if it works for you, keep it.
Not sure if it works for someone else even when close to you. At least not without alteration. The direction of the buildung/window and the height of the window matters and there maybe other factors.
I am happy that I can use an azimuth range only :wink:

115

it wasn’t a science reference. it was a joke.

However, your point is moot (and yes I used the correct usage of the word “point” that time :wink:) the angular size of the sun doesn’t change. So the difference between those two drawings is useless in the real world.

but the two intersecting lines do help make my point that the sun does act as a “point” source (but a big one) since from every “point” on the suns surface the light radiates out from that “point”. it’s the exact reason why we have both total shadows and partial shadows in an eclipse.

pedantry isn’t helping your case.

face it - a rectangular model won’t work for most locations at all times of the year no matter how much you want it to.

I admit I was wrong too.

116

If it can help, here is:

a button

type: button
name: Sun bothers me
icon: 'mdi:sunglasses'
tap_action:
  action: call-service
  service: script.fire_sunbothers

That triggers a script:

fire_sunbothers:
  sequence:
    - alias: "Fire SUN_BOTHER event"
      event: "SUN_BOTHERS"

That triggers an automation:

- alias: Write entry when sun bothers me
  trigger:
    platform: event
    event_type: "SUN_BOTHERS"
  action:
    service: notify.bothersome_sun
    data_template:
      message: >
        {{ now().strftime('%d/%m/%Y %H:%M:%S') }}, {{ states.sun.sun.attributes.azimuth }}, {{ states.sun.sun.attributes.elevation }}

That writes the azimuth and elevation of the sun to a file when the button is tapped :slight_smile:

Home Assistant notifications (Log started: 2021-05-21T12:22:09.804360+00:00)
--------------------------------------------------------------------------------
21/05/2021 14:22:09, 198.61, 58.39
21/05/2021 14:22:11, 198.61, 58.39
1 Like
117

Yes you are lucky. If you got time and if you feel like doing it check the azimuth at the exact time that the sun starts to shine in your home and get the same value after a week. Find their difference and divide it by the numbers of days (7 in the above example). You just have to replace the your number with 0.31 of the sensor.

Of course I can understand that you probably will have the same value of azimuth (or just a minor change)