PDA

View Full Version : A Question About the Moon-Venus-Jupiter Triangle In The Sky



Mr. Milton Banana
2008-Dec-03, 04:48 PM
I'm in the New York City area (northeastern USA). Looking south, I see the crescent moon-Venus-Jupiter-triangle.

My question is-which is Venus, and which is Jupiter? I'm guessing the bright dot to the immediate right of the crescent moon is Venus, because it's brighter. The other dot-Jupiter-is further away, so it's dimmer.

Am I right?

Hornblower
2008-Dec-03, 05:11 PM
I'm in the New York City area (northeastern USA). Looking south, I see the crescent moon-Venus-Jupiter-triangle.

My question is-which is Venus, and which is Jupiter? I'm guessing the bright dot to the immediate right of the crescent moon is Venus, because it's brighter. The other dot-Jupiter-is further away, so it's dimmer.

Am I right?
You are right. Jupiter is fainter despite its vastly larger size, because of its greater distance from both the Sun and the Earth.

Mr. Milton Banana
2008-Dec-03, 05:18 PM
Cool!! This is the first time in my life that I've seen both planets with the naked eye. (I'm too poor to afford telescopes.)

I should try and view them with binoculars. I can *almost* see a slight tinge of color with Jupiter, which makes sense given its clouds. Or perhaps that's just my imagination, and it's the atmosphere.

Nick Theodorakis
2008-Dec-03, 05:47 PM
Cool!! This is the first time in my life that I've seen both planets with the naked eye. (I'm too poor to afford telescopes.)

I should try and view them with binoculars. I can *almost* see a slight tinge of color with Jupiter, which makes sense given its clouds. Or perhaps that's just my imagination, and it's the atmosphere.

You've probably seen at least Venus before and just didn't know it.

It's possible to see the Galilean moons of Jupiter with binocs, if you mount them on a tripod, or have a very steady hand. Although, it's kind of low now so the seeing might not be too good.

Nick

Mr. Milton Banana
2008-Dec-03, 11:48 PM
You've probably seen at least Venus before and just didn't know it.

It's possible to see the Galilean moons of Jupiter with binocs, if you mount them on a tripod, or have a very steady hand. Although, it's kind of low now so the seeing might not be too good.

Nick

...and a third way would be to lean against a tree or building, while looking at Jupiter through binoculars. I figure that could keep me fairly steady.

I was too tired to try today-maybe tomorrow.

Nick Theodorakis
2008-Dec-04, 03:37 PM
...and a third way would be to lean against a tree or building, while looking at Jupiter through binoculars. I figure that could keep me fairly steady.

I was too tired to try today-maybe tomorrow.

Sky and Telescope has an online Jupiter's Moons Utility (http://www.skyandtelescope.com/observing/objects/planets/3307071.html) to help you confirm what you are seeing.

Nick

jfribrg
2008-Dec-04, 05:06 PM
You've probably seen at least Venus before and just didn't know it.

It's possible to see the Galilean moons of Jupiter with binocs, if you mount them on a tripod, or have a very steady hand. Although, it's kind of low now so the seeing might not be too good.

Nick

Steady hand or not, the Galilean moons are easy. My binoculars are good quality, but only 7X, and still I have no trouble seeing them. On the other hand, even with my 6" reflector and filters, I've never made out the bands on Jupiter, but that may be due to my colorblindness. Also, I've never tried to see the crescent of Venus. Tonight, if the clouds do not interfere, won't be able to say that ever again.

Nick Theodorakis
2008-Dec-04, 06:12 PM
Steady hand or not, the Galilean moons are easy. My binoculars are good quality, but only 7X, and still I have no trouble seeing them. On the other hand, even with my 6" reflector and filters, I've never made out the bands on Jupiter, but that may be due to my colorblindness. Also, I've never tried to see the crescent of Venus. Tonight, if the clouds do not interfere, won't be able to say that ever again.

I've had better luck seeing Venus's crescent before the sky gets dark.

Nick

Hornblower
2008-Dec-04, 11:13 PM
Right now Venus appears as a small gibbous shape. It will not be a crescent until late January, and it really will be prominent in February and early March. It will get larger and easier to see as it approaches Earth.

Romanus
2008-Dec-06, 04:06 PM
In my 4.5" telescope, it currently takes about 72x to clearly show Venus's phase, and the low altitude makes the image boil noticeably. Eagerly looking forward to its crescent phase, as well.

toothdust
2008-Dec-06, 09:43 PM
I should try and view them with binoculars. I can *almost* see a slight tinge of color with Jupiter, which makes sense given its clouds. Or perhaps that's just my imagination, and it's the atmosphere.

Hmm. Good question. Is it reddish because you know it is and your brain is filling in the blanks? Or does it perhaps register tot he naked eye as slightly reddish/orange?

Try looking through something a little more powerful than binoculars (if you have access to something). I looked through my parents 45x power spotting scope, and I could see the Galilean Moons clear and bright, as well as 2 distinct red cloud bands on the planet.

mugaliens
2008-Dec-07, 02:15 PM
I should try and view them with binoculars.

Several people have expressed confusion here and elsewhere over what the numbers mean when it comes to binoculars, and what they should look for if they're buying binocs for astronomy purposes.

Binocs have two numbers: Magnification x Objective. Example: 11x80.

For handhelds, your magnification should be kept below 12x for stability. More than that, and your eyeballs are going to be doing the flamenco inside your sockets. On a tripid, you can use magnifications of 15x to 30x. Beyond that, you really should invest in a telescope!

Your objective size (the second number) must be divided by its magnification (the first number) to determine the binocular's exit pupil, which indicates the binocular's light gathering/amplification ability. Thus, you're better off with a 12x60 than with a 15x60 if you want to see dim objects, as a 12x60's exit pupil is 5, while a 15x60's exit pupil is only 4.

The higher the exit pupil, the more light will reach your eyes. For astronomy, you'll want a binocular with an exit pupil of 5 or better.

stevenspray
2008-Dec-07, 10:19 PM
I should try and view them with binoculars. I can *almost* see a slight tinge of color with Jupiter, which makes sense given its clouds. Or perhaps that's just my imagination, and it's the atmosphere.

I thought this myself once but soon came to realise that it was due to Earth's atmosphere:(