# BigTimer node question - Sunset message confusion

**URL:** <https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448>\
**Category:** General\
**Created:** [28 June 2022 09:06 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448 "2022-06-28T09:06:15Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [28 June 2022 09:06 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/1 "2022-06-28T09:06:16Z")

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I am using the `BigTimer` node and have noticed something of _interest_ (to me).

Back story.  
Daily at sunset I get a message indicating sunset.  
After a delay my clock notifies me. Ok, that time is not specifically SUNSET, but it does _track_ the months and you can _see_ the trend.  
(Oh, I am in Sydney OZ)

June 21 is **the shortest day of the year**. I'll give a day or so either way.

So, this month I've seen this _signal_ happening and it is slowly creeping past 18:00 (local) to 18:01, 02, 03, and so on.  
On 21'st June it happened at 18:11/2. Again I'm not too fussed with second precision as I only see HH:mm on the clock.

So: 18:12 (call it) is **the shortest day of the year**.... Days after that get longer. IE: Sun rises sooner and sets later.

So why is it today (28 June) the _signal_ is happening at 18:14?

I'm confused.  
Someone - please?  
I've asked someone (via phone) who is into the planets and stuff and they couldn't answer me.  
I'm asking here not to _put you on the spot_ but because here, the people understand what/how that node works (no blame intended) and may have a better understanding of what is going on.

Thanks.

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [28 June 2022 10:27 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/2 "2022-06-28T10:27:16Z")

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> [@Trying\_to\_learn](#):
>
> So: 18:12 (call it) is **the shortest day of the year**.... Days after that get longer. IE: Sun rises sooner and sets later.

Not necessarily. After the shortest day the sun may still rise later, but set even more later, so the day is longer. Look up the times of your local sunrise/sunset to check before assuming it is a node-red issue. Also check at what time you are getting the signal from the bigtimer node so you can compare them directly with what they should be. Use a debug node configured to output to the console then it will go to syslog so you can check it later. You can't submit an issue against the node because it does not have a github (or similar) repository, or at least it didn't, which is one of the reasons I don't use it.

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**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [28 June 2022 10:33 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/3 "2022-06-28T10:33:37Z")

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I wasn't saying it was a node-red issue.

I asked someone who knows about the planets and that stuff, but over the phone they didn't understand the question.

Maybe I can't talk.... (Dunno)  
I was asking here as the people here know how things work and as _they_ wrote the code to make the node to give sunset times they would understand the maths also.  
So asking here it is better in a lot of ways.

To use the debug node as you say it will take another.... 360 days for it to happen again.  
I don't know how to fake dates into such nodes.

`Chron Plus` would/could give the same values... But for the shortest day.... It is 6 days behind me now.  
Again: I can't test the two to compare them for that.  
I could see if they both give the same sunset time, but that isn't exactly what I was asking.

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**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [28 June 2022 10:43 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/4 "2022-06-28T10:43:38Z")

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Maybe some useful graphs/numbers here to help compare - [Sunrise and sunset times in Sydney](https://www.timeanddate.com/sun/australia/sydney)

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [28 June 2022 10:44 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/5 "2022-06-28T10:44:22Z")

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There are various implementations of the sunrise calculations and various nodes use different libraries. they are all approximations.

for your case, there is about 1m difference in daylight duration from 21st ~ 28th however, both the sunrise AND the sunset time have moved...

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/0/a/0a9073d9d33e0bfeac08ab402944511328f3ff49.png)

Source: [Sunrise and sunset times in Sydney](https://www.timeanddate.com/sun/australia/sydney)

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [28 June 2022 10:49 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/6 "2022-06-28T10:49:56Z")

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> [@Trying\_to\_learn](#):
>
> I wasn't saying it was a node-red issue.

Neither was I, you seem to have ignored my suggestion

> [@Colin](#):
>
> Look up the times of your local sunrise/sunset

But I see others have done it for you.

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**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [28 June 2022 11:07 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/7 "2022-06-28T11:07:15Z")

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So given all this information - and sorry I didn't look at the table (or even get it) before asking - these _8 days_ are in a bit of _flux_ to their times and so this is not unusual.

It was only a couple of minutes difference (ok, 2.... but that's a couple) it is _normal_.

I am now blushing.

I had never noticed this before, as much as I try to keep my eyes open.  
I guess the last couple of years with things I haven't been in front of the display at that specific time and noticed it.

Greatest apologies if it is seen as _Crying wolf_.  
I just didn't understand the mechanics of what was happening in the bigger picture.

# Sorry.

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**Author:** ![mudwalker](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@mudwalker](https://discourse.nodered.org/u/mudwalker)\
**Post date:** [29 June 2022 07:17 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/8 "2022-06-29T07:17:25Z")

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@Trying_to_learn

[You might find this useful](https://en.wikipedia.org/wiki/Analemma#Earliest_and_latest_sunrise_and_sunset) in explaining why this happens

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<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [29 June 2022 11:19 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/9 "2022-06-29T11:19:29Z")

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Thanks very much for that.

I've started reading it but all those _big words_ it will take some time to process and understand.

(But seriously: Thanks. I was suspicious of something like that but just didn't get it.)

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [13 July 2022 11:19 UTC](https://discourse.nodered.org/t/bigtimer-node-question-sunset-message-confusion/64448/10 "2022-07-13T11:19:59Z")

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