Way to calculate day/night for a specific body

[Kilostream]

I'm trying to find out if anyone knows of a tool to work out when a certain spot will be in daylight.

Essentially, I have set myself the challenge of taking an SRV up mt nevrest - the colossal mountain on Nervi 3a.
It just so happens that whenever I've had time to do it, it's always been night when I flew there (made my third visit to try about 20 minutes ago), and whilst I think I'm up to the challenge of making the trip, it does need to be daylight when I do it - it's black as pitch at night and the crevasses are not to be messed with!

I looked at the stats in system map, and it said the orbital period around the planet is nine days, but I've no way to plug in the co-ordinates of the mountain to find out when the next sunrise there will be - I'm assuming the nights will be 4.5 days long (as it has a 9 day orbital period and is tidally locked to its host planet) and the days 4.5 days long but I've no idea where in that cycle the mountain is so looking there didn't really help.

If anyone knows a way to work it out, I'm ready to be educated and would appreciate the help planning the trip as leaving it to chance has proven a poor strategy so far!

 

[znôrt]

if it's tidally locked odds are the mountain will always be in the shadow?

 

[Ian Doncaster]

I'm trying to find out if anyone knows of a tool to work out when a certain spot will be in daylight.

This is not absolutely impossible to calculate - but it is really difficult. For a moon tidally-locked to its parent body which then independently orbits the star you would need to know (most of which you can just read off in-game, though not necessarily precisely enough):

- the orbital period of the parent body
- the orbital/rotational period of the moon
- the eccentricity of the moon's orbit
- the angle at which the moon's orbit is tilted to the planet's orbit
- the angle at which the moon's rotation is tilted to its orbit
- the surface coordinates of the point

You would then need to take a few sunrise-sunset measurements to find out where in its complex 'year' and 'day' the moon and planet were, to get a baseline to predict from.

I don't believe that anyone has made a general purpose tool to do these calculations (and it's tough enough I don't expect anyone to...). About the only hope for it is if Frontier ever implements an Orrery view which includes the FE2/FFE features of being able to advance or rewind time.

 

[Kilostream]

if it's tidally locked odds are the mountain will always be in the shadow?

No, because the thing it is tidally-locked to is a planet and not a star, so when it is between the planet and it's star, it'll be light on the side facing away from the planet, and when the planet is between the star and it, it'll be lit on the other side (unless there's an eclipse).

And @ Ian Doncaster - thanks for the comprehensive reply, although it sounds like I'd have to wait for the tool to be developed, which, given this is probably the first time I've needed this information and I can't think of too many other occasions when I would need it, is probably not going to be top of anyone's priority list!
Perhaps I'll ask those guys in the occupied escape pods over there - they look like they've been here a while......

 

[Ian Doncaster]

If you want to make some rough estimates that should hold for at least a few moon-days, that's a lot easier than a generalised prediction.:

1) Fly north or south to the pole nearest to the summit and hover about 100m up. Use your pitch indicator to measure the angle of the sun above or below the horizon.

If it's above the horizon at the pole, it's currently summer. The summit will certainly be in light 4.5 days later, and probably at other times, with larger windows the closer the summit is to the pole. You'll be fine just waiting half a local day and returning.

If it's below the horizon at the pole (which is seeming likely), then measure the angle more carefully. Anything within that angle of the pole (e.g. if the sun is 15 degrees below the horizon, anything between 90 and 75 degrees latitude) will be in permanent darkness - come back at a better time of the year.

If it's below the horizon, but not enough to be permanent darkness at the summit coordinates, then you have a bit more to work out, go to step 2.

2) Fly back to the summit, then fly due east (you will need to continually adjust course for this) until sunrise at ground level. Make a note of the longitude, then keep flying due east until the sun sets behind you, when you make another note of the longitude at sunset.
(Try to do this all fairly quickly, though on a 9-day local day you don't have to rush *too* much)

You then have a number of degrees currently between sunrise and sunset.

Now, the sunrise and sunset will still move at the rotational speed regardless of latitude - for a 9-day rotation, 40 degrees a day. You know where it currently is, and you know where the mountain is, so you can work out how long until the sun rises, and how long you have then until it sets. If that's at an inconvenient time, add the ~9 days and try again.

 

[Kilostream]

Thanks, Ian!

Im fairly good at flying roughly to co-ordinates in SC and dialling out the error when I drop out of glide, so my current plan is to try your idea to at least get an estimated time until sunrise (I remember the mountain is roughly 23 deg north and 110 deg east, but can't remember the orbital tilt).
Although, I've half a idea now I have a plan that involves it still being night, I might find on arrival this time that it'll be daylight anyway!

:edits: Oh! I just logged in and instead of black, I see a dim grey smudge! I think it's getting light! Maybe some drunk SRV driving when I get back from the pub in a few hours!