Daylight hrs and Latitude

[gorilla ganja]

Here is a great site for finding daylight hrs for your Latitude on any particular day .http://astro.unl.edu/classaction/animations/coordsmotion/daylighthoursexplorer.html
Just put in your Latitude and set date then hit enter.

 

[gunnaknow]

You need to include civil twilight when working out the approximate photoperiod. Civil twilight occurs when the Sun is between 0 degrees and 6 degrees below the horizon; when there is still sufficient light, under clear weather conditions, for terrestrial objects to be clearly distinguished.

If you wish to work out the approximate photoperiod in your area, you can go to the site below:

http://www.mindspring.com/~cavu/sunset.html

Scroll down to "Step 1 - Enter your location" and then subsection "By Latitude/Longitude". Tick the box next to "Enter latitude as offset from the Equator" and then enter your latitude and longitude in the box beneath that. Enter as N42-44 W071-35 or S42.74 E071.6, for example.

Next, scroll down to "Step 4 - Control of Results". Under "How Long" tick the box next to "1 year". Just beneath that, under "Text Color", tick the box next to "Black".

Finally, scroll to "Step 5" and press "COMPUTE".

You will then be presented with a table showing the civil twilight period for each day of the year. To work out the approximate photoperiod for a particular day, count the number of hours and minutes between "CTS" (civil twilight start) and "CTE" (civil twilight end). You can then print off the page for safe keeping, and underline the day with your preferred photoperiod.

It takes a few minutes, but at least you'll have reliable information, and you won't need to do any calculations again.

gunna

 

[gorilla ganja]

gunnaknow, you are right about the twilight. There is some debate as to how much low light before it will effect flowering. I like to keep it simple. In my area the longest day has about 17hrs of daylight, I add 1 hr for twilight and set my babies on a 18/6 schedule.
Thank you for adding to the thread.