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View Full Version : Discussion: June 25th Conjunction: Mercury, ...



Fraser
2005-Jun-23, 04:29 PM
SUMMARY: Few celestial events attract such widespread media attention as what is inappropriately named a planetary alignment. Because of their orbits and distances from the sun, the planets do not actually line up. Occasionally however, two or more planets do appear to gather close together in the sky as seen from here on Earth. An event such as this is known as a planetary conjunction. Late June offers observers, especially those in the northern hemisphere, a chance to witness just such a conjunction of Mercury, Venus and Saturn.

View full article (http://www.universetoday.com/am/publish/conjunction_mercury_venus_saturn.html)

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antoniseb
2005-Jun-23, 04:50 PM
I think the only times I've ever seen Mercury were during conjunctions like this. It's good to get out two or three evenings in a row so you can see how fast the planets move with respect to each other, and so you can be confident that you've seen the right things.

sploo22
2005-Jun-25, 08:38 PM
Because of their orbits and distances from the sun, the planets do not actually line up.

This is inaccurate. Imagine a line from the earth into the sky passing through roughly the center of the group of planets. All three planets lie very close (astronomically speaking) to that line, as does the earth. Thus, within a margin of error, they are collinear in three-dimensional space.

For an illustration of this, see http://www.fourmilab.ch/cgi-bin/uncgi/Solar. (You may want to increase the image size from 320 to around 800 pixels to make it clearer.) Notice how Earth, Mercury, Venus, and Jupiter lie close to the same diagonal line.

Spacemad
2005-Jun-25, 10:41 PM
I've been on the look out this last week for this conjunction - so far I've only been able to see Venus - I even took a picture with my digicam but, although a slight point of light was visible - if you knew where to look!, I had to delete it as it was of very bad quality!

Unfortunately the sky is clouded over tonight so no planets are visible. If the sky is clear tomorrow night I shall do my best to see if I can spot them.

aeolus
2005-Jun-26, 03:45 PM
Originally posted by sploo22@Jun 25 2005, 08:38 PM
This is inaccurate. Imagine a line from the earth into the sky passing through roughly the center of the group of planets. All three planets lie very close (astronomically speaking) to that line, as does the earth. Thus, within a margin of error, they are collinear in three-dimensional space.

Its not innaccurate. A planetary alignment is defined as having at least 2 planets line up with the sun. Just like you said, during the conjunction the planets line up on a diagonal, which would have to be the case to see somethign like this.

For an alignment, draw a ray out of the sun through the solar system, and have at least two planets lie on the line. It's merely a conjunction as viewed from the sun.

antoniseb
2005-Jun-27, 12:54 PM
I saw it, and it was pretty cool. Nice to see Mercury again.

aeolus
2005-Jun-27, 03:42 PM
I was at work the past three nights, but I wasn't gonna let that ruin the fun. I did my part (brought binoculars and scheduled my break for about 10pm) and the clouds did theirs (stayed out of the way).

The coolest thing about watching conjunctions (especially with the interior planets) is seeing just how fast they move positions day-to-day. I hope it's nice out tonight again!

Spacemad
2005-Jun-28, 11:28 PM
I've still not been able to see the conjunction :( Like aeolus I've been working these last three nights but unlike him I've not been able to "Schedule " my breaks - I have to take them when they get round to it! :blink: I shall just have to wait till Saturday & see if I'm lucky enough to see the tail end - if the weather cooperates that is!