Tomorrow Daylight Prediction

[radioham]

Is it still unreliable (as stated in the help)? How unreliable? I guess it is as I have noticed, for example today in Vancouver Canada, the prediction was for an increase of 2 min 59 secs earlier in the day and then 3 min 2 secs when I checked later in the evening, so the prediction for the same next day (February 1, 2016) has changed.

[beteljuice]

You need to understand that quite apart from the seriously complex astrological math there are the mundane considerations of your altitude above Mean Sea Level and by the way do you live on a flat plain with no obstructions to the Suns transit throughout the year ?

I thought not.

Do you have serious differentials to the predicted ?

[steve]

The code for this hasn't changed. Apart from the inaccuracies involved, and the points raised by beteljuice, I believe the figure changes at midnight UTC rather than local time, due to the way the library routines operate.

[radioham]

Thanks for your comments and sorry if my question sounded like a complaint. It was not, just trying to learn more about the software, which is excellent. I did a quick comparison using a NOAA calculator (rounded to minutes) and the prediction seems to agree today: http://www.esrl.noaa.gov/gmd/grad/solcalc/index.html

It is encouraging to know how many minutes of daylight we gain each day at this time of the year, which can be quite gloomy. It is a nice touch for others viewing the web site.