View Full Version here: : Neptune in the Earths Shadow
NQLD_Newby
15-08-2008, 04:29 PM
Hi everyone, I was just tossing up a few objects to have a look at tonight, and finding them in my star programme on the PC. When I found neptune it shows it in Earths shadow for more or less the entire night tonight. What I was wondering is if this would be visible to some of the guys or gals with much larger scopes than mine? I think it would be very cool if my programm is correct and it was visible.
Sunday morning 17/08/08 @ 2.00am EST, it actually enters the shadow again. This should be visible as it darkens I would presume. Anyway just thought it would be interesting to see and thought others might find it so also.
It would darken a little, like 1/100000000th or something rediculous, probably only detectable by electronic means, if at all.
The size of the earth as seen from Neptune would be only a fraction of that of the Sun, so we would be passing across the Sun's disk kinda like we see the Transits of Mercury and Venus, or even the Jovian moons cross Jupiter.
Edit: Actually, wouldn't be too difficult to calculate.... hmmm
Okay, here's a rough as guts answer. (Mean diameters from Wikipedia)
Diameter of Sun = 1392000km
Diameter of Earth = 12742km
or 1/109th the diameter of the Sun.
D1^2 / D2^2 = 11934.47
So I guess thats 1/11934th the area of the Sun.
That doesn't take into account the Earths orbital distance and therefore it's slight apparent increase in diameter as seen from Neptune. 'Tis beyond my math ability!, probably could work it out with Earths and Neptunes orbits and some trig.
NQLD_Newby
22-08-2008, 03:43 PM
Hmmmmmmm gotta hate it when you ask a silly question don't you. I should have realised this, as it really is common sense. Guess I was excited at the possibilities lol, thanks Mr B.
Starkler
22-08-2008, 03:46 PM
Lets hope some of those Neptunians get some earth transit pics and post em up here :lol:
LOL Geoff.
Hey, I wonder if any of the interplanetary probes has ever been, or will be, in a position to photograph a Transit of Earth.
NQLD_Newby
24-08-2008, 02:29 PM
ahahahahah Ron, Maybe they will :rofl:
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