Comments and questions about the
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APOD Robot
- Otto Posterman
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by APOD Robot » Thu May 23, 2019 4:08 am
Moons Near Jupiter
Explanation: On May 20, a nearly Full Moon and Jupiter shared this telephoto field of view. Captured when a passing cloud bank dimmed the moonlight, the single exposure reveals the familiar face of our fair planet's own large natural satellite, along with bright Jupiter (lower right) and some of its
Galilean moons. Lined up left to right the tiny pinpricks of light near Jupiter are
Ganymede,
Europa, [Jupiter] and
Callisto. (That's not just dust on your screen ...) Closer and brighter, our own natural satellite appears to loom large. But Ganymede, and Callisto are physically larger than Earth's Moon, while
water world Europa is only slightly smaller. In fact, of the Solar System's six
largest planetary satellites, Saturn's moon Titan is missing from the scene and a fourth Galilean moon, Io, is hidden by our ruling gas giant.
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De58te
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by De58te » Thu May 23, 2019 10:10 am
But I see 4 moons around Jupiter! One is bigger than the rest, nearly half the size of Jupiter. What's it called? Oh, wait! That was dust on my screen.
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orin stepanek
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by orin stepanek » Thu May 23, 2019 12:40 pm
Nice photo! Really is hard ot see the Jovian moons; but they are there!

Orin
Smile today; tomorrow's another day!
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E Fish
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by E Fish » Thu May 23, 2019 1:21 pm
I always try to look at the photo without reading the explanation first so I can test myself. I want to guess what's going on before I read the description, and I'm pleased to say that today I saw Jupiter and the Galilean moons (called the Medici stars by Galileo) very quickly.
The artistic composition of this photo is beautiful.
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Chris Peterson
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by Chris Peterson » Thu May 23, 2019 1:27 pm
orin stepanek wrote: ↑Thu May 23, 2019 12:40 pm
Nice photo! Really is hard ot see the Jovian moons; but they are there! :D
It's quite possible to see the Jovian moons with the naked eye. You just need to use something like a phone or power line a few hundred meters away to block Jupiter itself, and then one or more moons pop out, assuming they're well placed at the time. I've done it a number of times.
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BDanielMayfield
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by BDanielMayfield » Thu May 23, 2019 2:05 pm
Chris Peterson wrote: ↑Thu May 23, 2019 1:27 pm
orin stepanek wrote: ↑Thu May 23, 2019 12:40 pm
Nice photo! Really is hard ot see the Jovian moons; but they are there!
It's quite possible to see the Jovian moons with the naked eye. You just need to use something like a phone or power line a few hundred meters away to block Jupiter itself, and then one or more moons pop out, assuming they're well placed at the time. I've done it a number of times.
Nice. I'll have to try that sometime. It reminds me of the starshade idea being planned for use with exoplanet finding space telescopes of the future.
Just as zero is not equal to infinity, everything coming from nothing is illogical.
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BDanielMayfield
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by BDanielMayfield » Thu May 23, 2019 5:45 pm
Has anyone ever been able to take a shot capturing all six of our system's largest moons (plus Jupiter and Saturn of course) in the same frame? Such a photo opp might have been possible back in April.
Space.com wrote:If you're up late in the coming nights, you may want to pay attention to the waning gibbous moon — for it will be visiting the two largest gas giants of our solar system early on Tuesday and Thursday mornings (April 23 and 25).
Just as zero is not equal to infinity, everything coming from nothing is illogical.
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orin stepanek
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by orin stepanek » Thu May 23, 2019 6:27 pm
Orin
Smile today; tomorrow's another day!
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Avalon
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by Avalon » Thu May 23, 2019 8:27 pm
I amazed that the moons of Jupiter are so visible with a thin cloud layer between them and our eyes.
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florid_snow
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by florid_snow » Fri May 24, 2019 12:19 am
BDanielMayfield wrote: ↑Thu May 23, 2019 5:45 pm
Has anyone ever been able to take a shot capturing all six of our system's largest moons (plus Jupiter and Saturn of course) in the same frame? Such a photo opp might have been possible back in April.
Space.com wrote:If you're up late in the coming nights, you may want to pay attention to the waning gibbous moon — for it will be visiting the two largest gas giants of our solar system early on Tuesday and Thursday mornings (April 23 and 25).
Such a photo is possible with compositing techniques, maybe really zoomed out. But given their orbits, Jupiter and Saturn are only very close together in the sky every 20 years. I'm very excited for the Great Conjunction of 2020!
I mean, during the last Jupiter and Saturn great conjunction in 2000 the best astrophotos were still being taken with film! I'm really looking forward to those few nights in late December 2020. I'm sure the pictures will be good. But to seem them oneself, all at the same time, in one telescope eyepiece! I hope I get to see it and share the view with others!
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Boomer12k
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by Boomer12k » Fri May 24, 2019 3:30 am
Really nice, and eerie image... I found it interesting to see Moons of Jupiter...as I have taken pictures of Jupiter, but not enough exposure to get the moons...at least with my Camcorder.
:---[===] *
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bls0326
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by bls0326 » Fri May 24, 2019 1:12 pm
Chris Peterson wrote: ↑Thu May 23, 2019 1:27 pm
orin stepanek wrote: ↑Thu May 23, 2019 12:40 pm
Nice photo! Really is hard ot see the Jovian moons; but they are there!
It's quite possible to see the Jovian moons with the naked eye. You just need to use something like a phone or power line a few hundred meters away to block Jupiter itself, and then one or more moons pop out, assuming they're well placed at the time. I've done it a number of times.
Is there any record of anyone seeing the Jupiter moons before Galileo and his telescope? Based on your comment, someone should have even if they had no idea what they were seeing. Maybe Galileo knew what he wanted to look at before his telescope was ready.
Brian
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Chris Peterson
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by Chris Peterson » Fri May 24, 2019 1:18 pm
bls0326 wrote: ↑Fri May 24, 2019 1:12 pm
Chris Peterson wrote: ↑Thu May 23, 2019 1:27 pm
orin stepanek wrote: ↑Thu May 23, 2019 12:40 pm
Nice photo! Really is hard ot see the Jovian moons; but they are there! :D
It's quite possible to see the Jovian moons with the naked eye. You just need to use something like a phone or power line a few hundred meters away to block Jupiter itself, and then one or more moons pop out, assuming they're well placed at the time. I've done it a number of times.
Is there any record of anyone seeing the Jupiter moons before Galileo and his telescope? Based on your comment, someone should have even if they had no idea what they were seeing. Maybe Galileo knew what he wanted to look at before his telescope was ready.
No indication of it. Presumably anybody who encountered the right circumstances for a chance glimpse would have simply considered them to be stars. It would take multiple sightings to detect their motion.
I've shown people Saturn through a telescope, and while waiting to look, they observed that the little spot in the sky was oval shaped. People with good vision can see that. But I've never heard of that being recorded in antiquity, either.
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neufer
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by neufer » Fri May 24, 2019 2:23 pm
Chris Peterson wrote: ↑Fri May 24, 2019 1:18 pm
bls0326 wrote: ↑Fri May 24, 2019 1:12 pm
Chris Peterson wrote: ↑Thu May 23, 2019 1:27 pm
It's quite possible to see the Jovian moons with the naked eye. You just need to use something like a phone or power line a few hundred meters away to block Jupiter itself, and then one or more moons pop out, assuming they're well placed at the time. I've done it a number of times.
Is there any record of anyone seeing the Jupiter moons before Galileo and his telescope? Based on your comment, someone should have even if they had no idea what they were seeing. Maybe Galileo knew what he wanted to look at before his telescope was ready.
No indication of it.
It would have been before the invention of phone & power lines.
Art Neuendorffer
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Chris Peterson
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by Chris Peterson » Fri May 24, 2019 2:34 pm
neufer wrote: ↑Fri May 24, 2019 2:23 pm
Chris Peterson wrote: ↑Fri May 24, 2019 1:18 pm
bls0326 wrote: ↑Fri May 24, 2019 1:12 pm
Is there any record of anyone seeing the Jupiter moons before Galileo and his telescope? Based on your comment, someone should have even if they had no idea what they were seeing. Maybe Galileo knew what he wanted to look at before his telescope was ready.
No indication of it.
It would have been before the invention of phone & power lines.
But not twigs, or even stretched out string and rope.
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Nitpicker
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by Nitpicker » Fri May 24, 2019 7:36 pm
It is amazing what you can see once you know it is there.
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alter-ego
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by alter-ego » Sat May 25, 2019 4:16 am
Nitpicker wrote: ↑Fri May 24, 2019 7:36 pm
It is amazing what you can see once you know it is there.
Or more figuratively, as I like to say, hindsight is 20-10.
A pessimist is nothing more than an experienced optimist
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neufer
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by neufer » Sat May 25, 2019 2:45 pm
alter-ego wrote: ↑Sat May 25, 2019 4:16 am
Nitpicker wrote: ↑Fri May 24, 2019 7:36 pm
It is amazing what you can see once you know it is there.
Or more figuratively, as I like to say, hindsight is 20-10.
http://asterisk.apod.com/viewtopic.php? ... 25#p292325
Art Neuendorffer