Mun eclipse ummm...

[FancyMouse]

I just happen to want to think about this particular problem, and did a quick calculation:

Mun radius 200km, orbit radius 12Mm

Sun radius 261.6Mm

Kerbin orbit radius ~13.6Gm

So when Mun eclipse happens, it should be shadowing a big circle onto the Sun of radius

200k/12M*13.6G = 226.67Mm

wait but 226.67 < 261.6... that means Mun won't block the Sun completely. It should be just an annular eclipse. And there should still be some energy flow left at minimum during the eclipse, instead of "blocked by Mun" and cuts down to a complete zero. My calculation is ~25% (simple 1-(226.67/261.6)^2), but I'm not so sure since I assumed equal distribution of energy on the area of the sun we see, but this assumption may be false. A more reasonable assumption is equal distribution of energy on the surface of Sun, but I don't know how to calculate that.

Am I missing anything or any stupid calculation mistakes? If not, then I'll probably feel better about my RT comm network around Kerbin where I forgot to handle eclipses. And probably file a (not-so-important) bug to fix the energy flow?

[Hotaru]

Having by coincidence just witnessed a solar (Kerbolar?) eclipse from Kerbin orbit, my observation backs up your calculations:

The Mun is definitely noticeably smaller in diameter than the disc of the Sun, so this is an annular eclipse and at least a little energy should still be sneaking through around the edges. I don't know about the distribution of energy across the area of the disc, though, so I can't say if you're right about the amount of energy. I believe KSP determines an eclipse by where the center of the Sun is, not the edges, so you stop getting electricity precisely halfway through sunrise or sunset--it also doesn't seem to take into account local topography, which is especially noticeable on Minmus, where I've frequently noticed my ships continue receiving power long after the Sun has passed below the apparent horizon.

[magnemoe]

In KSP you loose all power in any eclipse, even if the body in not even visible against the sun. I once got an kerbin eclipse outside the orbit of Minmus and an Tylo eclipse in low Jool orbit.

[Asharad]

Mun won't block the Sun completely. It should be just an annular eclipse. And there should still be some energy flow left at minimum during the eclipse, instead of "blocked by Mun"

My latest trip to Minmus almost failed because Kerbin partially eclipsed Kerbol. I could see most of the sun, but my solar panels were blocked. Fortunately power was restored about 30 seconds before impact.

[KerbMav]

Seems that it is enough for the center of the sun to be eclipsed to block it. Way easier to calculate for sure.

[stibbons]

it also doesn't seem to take into account local topography, which is especially noticeable on Minmus, where I've frequently noticed my ships continue receiving power long after the Sun has passed below the apparent horizon.

On Minmus, at least, there is a long-standing bug concerning solar panels on the dark side. I haven't done much testing on other bodies though.

[lajoswinkler]

Kerbol behaves like a point energy source. The glowing ball is just for looks. Therefore if a planetary body obscures part of that ball, nothing happens, but as soon as the center point of Kerbol gets obscured, flare is gone and so is your energy source.

Granted, there are exceptions to this rule which apply when the "shadow mesh" of the bodies doesn't match the terrain mesh. Bop is a perfect example.

[KerbMav]

which is especially noticeable on Minmus, where I've frequently noticed my ships continue receiving power long after the Sun has passed below the apparent horizon.

The planets are perfect spheres for these calculations, also for RemoteTech last time I used it.