Page 1 of 1

How is Solunar data calculated? Is it accurate for lat/long?

Posted: Mon 11 Jan 2010 10:58 am
by PolwinDave
Hi
I've been looking at some software & a couple of sites for getting solunar data - Sun & Moon set/rise times etc. I seem to get different answers from Cumulus (and differences between the other sites/software) for rise/set times and I was wondering how it's calculated in Cumulus and how accurate it is for a given latitude/longitude.
I'm ultimately trying to work out the correct solunar charts for my exact location but because I need to do this on a hourly basis from November through February, I need to start with accurate info on rise and set times for both sun and moon.
Can you help on the accuracy part, Steve?
Also, does anyone know of a site/software that would give accurate data for a specific UK location?
TIA
Dave

Re: How is Solunar data calculated? Is it accurate for lat/long?

Posted: Mon 11 Jan 2010 11:31 am
by steve
I use an open source library for the calculations, and I think they are pretty accurate. They seem to compare well with the figures given on the well-known web sites. There's an issue with the comparison of today's day length with tomorrow's because it tries to do it to the nearest second, and the routines seem to be accurate to the nearest minute.

Could you point me at the site(s) where you get a different answer from Cumulus, please?

Re: How is Solunar data calculated? Is it accurate for lat/long?

Posted: Mon 11 Jan 2010 12:58 pm
by PolwinDave
Dork award of the day goes to me - I had longitude set wrongly in configuration :oops:

Re: How is Solunar data calculated? Is it accurate for lat/long?

Posted: Mon 11 Jan 2010 1:12 pm
by werribee_au
ROFLMAO :lol:

Re: How is Solunar data calculated? Is it accurate for lat/long?

Posted: Mon 11 Jan 2010 1:13 pm
by werribee_au
Sorry Dave, had to laugh! :D

Re: How is Solunar data calculated? Is it accurate for lat/long?

Posted: Mon 11 Jan 2010 1:22 pm
by PolwinDave
No Worries :lol: