Allows customization of all aspects of the solar cycle. Use it to extend (or shorten) days, change dawn and dusk times, and so forth. Defaults to making days 4 times as long as vanilla.
You can also darken nights - make them more dangerous and lights more valuable. Still not scary enough for you? You can disable night vision too.
Most of these settings can be changed on the fly in a running game if you wish to experiment with different day lengths or transition times. But solar power users please take note: accumulators cannot be adjusted dynamically (i.e., restarting the Factorio app is required with each change).
Modded accumulators (such as in bob's mods and so on) should be adjusted with the accumulator settings.
Note: In Vanilla, only about 10% of the daily cycle is the darkest part of night. If you want to change the Dusk/Evening/Morning/Dawn times, these example values (in the same order) will give you a balanced day/night:
0.25, 0.3, 0.75, 0.8.
But please note, existing solar blueprints will be far from balanced in configurations like this.
Special thanks to Ranakastrasz for allowing incorporation of his flares -- an early lightsource intended to help with getting through longer nights.