What kind of experience will it be when you are on Pluto and on Sedna and they are at their farthest point from the Sun (aphelion) Pluto about 90 AU then and Sedna an unimaginable 900 AU. How bright will the Sun shine at Plutos farthest distance to the Sun at 90 AU ,and what about its brightness when you are on Sedna at its aphelion at 900! AU? When we send landers to Pluto and Sedna in the future ,do they need (extra) lights because of the dimness of the Sun? Can somebody explain these things?

Pluto:

Not too hard to bump up the aperture of the optics on the imaging system. Could also increase exposure time, don't think the Plutonians are going to move around enough to blur the picture.

Sedna:

Might need some image intensifier technology (like the starlight scopes the army has) but I suspect that they are not very accurate photometrically. Maybe they could be improved enough. Long exposures probably not a problem here, either.

Radar and deep infrared will still work.

If Sedna has an atmosphere, maybe a highly focused sonic range finder could build up images.

Don't panic. Remember that the emitted brightness of the full Moon is only 1/500,000 that of the Sun -- less than twice as bright as the Sun at Sedna's aphelion! Our retinal rods adapt to that quite well, and light-sensitive cameras will do even better.

How many years is it likely to be before a human nation sends landers to Pluto? 200 maybe?

And by then it probably won't be the USA or Russia or China doing the launching -- maybe Sri Lanka or Honduras...

It will be a bit dark at noon at Sedna when it is at aphelion ,am i right? And what is the magnitude of a full moon in a clear night sky? And what is the magnitude of the Sun as seen from Sedna at aphelion and at Pluto?

-12.7 (from google)



~ -11.8 According to Celestia



~ -18.3 Celestia again.

James

A bit of trivia stuck in my head: the magnitude of the Sun at Earth's orbit is -27; the magnitude difference of 9 (27 minus 18) between Earth's and Pluto's Sun is a brightness factor of about 4000.

FWIW...

--Bill

How does Celestia know the magnitude at a specified distance of a planet,Kbo object and of many stars?

Will it look like a (bit) darkness when you are walking on Sedna at 900 AU distance? A lander needs lights to look around on Sedna then i think. Is that true?

There's an equation to calculate the aparant magnitude ( i.e. those values ) from the absolute magnitude ( the mag of an object at a standard distance ) which we know for the sun.

Doug

Time for a shameless plug for my brightness calculator again: setting albedo, diameter and distances (star to X, viewer from X) will give you, Rem31, a good estimate to the brightness of bodies that are fully lit by the Sun.

To calculate the Sun's brightness at different ranges, Doug's right:

Apparent Magnitude = 2.5*log10(dist^2) - 26.73

dist is in AU. The figure -26.73 is the Sun's Absolute Magnitude.

Andy (edited the link)

Sorry but the link does not work. Can you help me to get the link succesfully? Thanks.

Celestia is a good alternative for calculating magnitudes at a specified distance. But can you help me with your link ? It doesnt work.

Try Brightness Calculator. A very valuable resource!

Michaelc