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Interesting Items...

Mike2 said:
Both are quite dim, hardly exciting.
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Tonight's the night, but weather forecast expectations indicate I will see sweet FA.

Local news bulletin this morning "move close together producing a bright light" - whoever writes this stuff haven't actually looked for themselves.
 
Black Hole said:
Tonight's the night, but weather forecast expectations indicate I will see sweet FA.

Local news bulletin this morning "move close together producing a bright light" - whoever writes this stuff haven't actually looked for themselves.
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Same here. And I think I heard a similar news report. Having never seen it before, I can't comment.
 
Is it just a coincidence that it is also the winter solstice?
I can't think of a reason it couldn't happen anytime, but I'm not a major in orbital dynamics.
 
prpr said:
What are the chances of that? When will it next happen?
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The solstices/equinoxes are to do with the inclination of the Earth's rotational axis relative to its orbit, so nothing to do with orbital mechanics as such. This is a "syzygy" - the alignment of three bodies (in this case a straight-ish line from Earth past Jupiter to Saturn), and predictable by orbital mechanics, but presuming the actual alignment could occur on any date the chances that it will occur on the date of the winter solstice is simply 1/365.

A conjunction such as this is complicated by the different inclinations of each planet's orbit (angle and orientation). The planets pass each other in the sky frequently (compared with 400 years)... but not necessarily as a "near miss".

That said, the actual probability could be influenced by long-term coincidences - for example: the probability that the 13th of the month (in the Gregorian calendar) is a Friday is not exactly 1/7, because it just so happens that the 400-year cycle of the calendar is an exact number of weeks (not by intention).

EEPhil said:
Having never seen it before, I can't comment.
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You won't have done, it's roughly every 400 years, but the fact remains that Saturn is very faint compared with Jupiter (due to their distances from Earth and the Sun), so if they got close enough to apparently merge (they won't unless you have bad eyesight), the combined brightness wouldn't be much more than Jupiter on its own.

Of more interest is whether they can be photographed (with detail such as the rings, bands, and satellites) in one frame. At closest they should be about 6' (minutes of arc) spaced, while Jupiter is about ½', and Saturn ¼'. 12x Jupiter diameter apart? Should make for some good photos in next month's Sky & Telescope gallery pages, but I don't have the gear to do it (even if I had a clear sky).
 
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Black Hole said:
A conjunction such as this is complicated by the different inclinations of each planet's orbit (angle and orientation). The planets pass each other in the sky frequently (compared with 400 years)... but not necessarily as a "near miss".
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I've done some research and found a useful academic (ie non-sensational) article: https://sparky.rice.edu/public-night/jupsat2.html

The average interval between Earth-Jupiter-Saturn syzygies is 19.86 years, so throughout the 21st century they occur on each 20th year. The separations for each are:

Date​
Minimum Separation (minutes of arc)​
28th May 2000​
68.9​
21st December 2020​
6.1​
4th November 2040​
72.8​
8th April 2060​
67.5​
15th March 2080​
6.0​
18th September 2100​
62.5​

...so actually there is a similar conjunction in 2080.
 
I'll look forward to that. I hope the seeing will be better. But will it be on the wither solstice? No, but very close to the spring equinox.
 
Black Hole said:
the chances that it will occur on the date of the wither solstice is simply 1/365.
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So every 20 years, times 365 then. 7300 years or so. Wow. If only it wasn't cloudy. Not sure if I've got an uncluttered view in the required direction either.
Will read the other sites later. Thanks for the info.
EEPhil said:
Not sure I'll make it into my 120's.
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If things carry on much like they are, I think I'll be lucky to get to my half those.
 
prpr said:
If things carry on much like they are, I think I'll be lucky to get to my half those.
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As I've been in close contact with a person who tested positive for covid for 3 days before she went back to hospital I might have a similar problem. :sick:
Oh well, no choice - nobody's coming to visit this xmas (Hoo-bloody-ray), and I've got a freezer full of food. I might be a free man again on the 28th.
 
Black Hole said:
Wellll.... that was a washout then (as bloody usual in this country, whenever there's something interesting to see - I'll tell you about my 1999 eclipse experience some time)!


Depends what you call "shit". The hype was, but the event wasn't.
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Did you look at my picture? Saturn is further away than Callisto. Nowhere near close enough. My definition of shit. Double star my ass.
 
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