Cmdr cookiehole's spreadsheet for calculating when jumps will be obscured by the planet's day/night cycle.
I've finally more or less finished my spreadsheet for calculating the elevation of jump targets on planetary surfaces (or the ship altitude necessary to see the target) and have also attached a short how-to.
The spreadsheet is on google sheets here, you'll need to make a copy or download it to use it.
Note that this is only for jump targets obscured by the planet's day-night-cycle and not by other planets, as these are much harder to measure and calculate