APOD: Moons and Jupiter (2016 Mar 03)

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Expand view Topic review: APOD: Moons and Jupiter (2016 Mar 03)

Photoshop job?!!

by larouchj » Sat Mar 05, 2016 1:39 pm

If I stretch the image I can clearly see a bad cut and paste job around jupiter!!! Stellarium is also showing different moon positions.
Looks like something wrong here! Anybody can confirm what I see!! So far, I think there is strong evidences that it is a photoshop Job!!! :evil:

Problem with APOD picture of March 3rd

by AndreCajolais » Fri Mar 04, 2016 8:52 pm

Although it is mentioned that Moons and Jupiter of February 23rd is a composite image, there is still a big problem with this image from Philip A Cruden - http://apod.nasa.gov/apod/image/1603/WA ... Cruden.jpg
The image is a false and a wrong Photoshop montage…

I made a simulation with Stellarium and SkySafari for February 23rd, at 23h00 Local and noticed that Jupiter - on the APOD picture - is located on the wrong side of the Moon.

Of course, the distance between the two elements is much farter than represented in this image, not to mention that exposing both elements correctly is pratically impossible, with the contrast of the almost full moon - that's why the author made the point that it is a composite image.

But still, the montage is wrong, as shown by both Planetarium programs.

AC

Re: APOD: Moons and Jupiter (2016 Mar 03)

by Chris Peterson » Fri Mar 04, 2016 4:47 pm

Fred the Cat wrote:Why couldn't ancients have thought that Jupiter was another star that had its own planets? Of course they rapidly shifted position but I might think that the ability to observe the moons of Jupiter without aide may have given insight into planetary arrangement very long before Galileo used his telescope and tried to record his conclusion.
You need to consider the strong bias they already had in thinking that the Sun and the stars were completely different things. And without aid, it would be very difficult to identify a pattern in Jupiter's moons.

Many individual shifts in understanding had to develop over the centuries before solar system models started coming together. And those shifts followed careful, scientific (or semi-scientific) observations, recorded and used by subsequent generations of observers. Pretechnological societies largely lacked that capability.

Re: APOD: Moons and Jupiter (2016 Mar 03)

by Fred the Cat » Fri Mar 04, 2016 4:38 pm

Why couldn't ancients have thought that Jupiter was another star that had its own planets? Of course they rapidly shifted position but I might think that the ability to observe the moons of Jupiter without aide may have given insight into planetary arrangement very long before Galileo used his telescope and tried to record his conclusion.

Re: APOD: Moons and Jupiter (2016 Mar 03)

by Chris Peterson » Fri Mar 04, 2016 3:17 pm

Markus Schwarz wrote:
neufer wrote:A lot of nearby 4th magnitude "stars" change their positions vis-a-vis Jupiter from night to night.
I don't get that :?: We see a lot of fixed stars in the night sky, i.e. stars that don't change their relative positions to each other (on a human time scale). Of course, they all change positions simultaneously because of Earth's rotation and motion around the Sun. And we have five "stars" that wander around the night sky and do change their positions relative to all the other fixed stars. What, then, do you mean by '4th magnitude "stars"'? And to be clear, I am thinking about ancient star gazers without sophisticated instruments.
I imagine that ancient stargazers were drawn to star patterns, not individual stars (other than the bright ones). The moons of Jupiter look like stars, but they show no pattern at all with respect to the stars, and only a subtle pattern (their linearity) with respect to Jupiter. It is easy to believe that observers occasionally noted the moons, but took them to be nothing more than dim background stars (not of much interest), gone the next night because Jupiter had moved.

Re: APOD: Moons and Jupiter (2016 Mar 03)

by Markus Schwarz » Fri Mar 04, 2016 3:07 pm

neufer wrote:A lot of nearby 4th magnitude "stars" change their positions vis-a-vis Jupiter from night to night.
I don't get that :?: We see a lot of fixed stars in the night sky, i.e. stars that don't change their relative positions to each other (on a human time scale). Of course, they all change positions simultaneously because of Earth's rotation and motion around the Sun. And we have five "stars" that wander around the night sky and do change their positions relative to all the other fixed stars. What, then, do you mean by '4th magnitude "stars"'? And to be clear, I am thinking about ancient star gazers without sophisticated instruments.

Re: APOD: Moons and Jupiter (2016 Mar 03)

by neufer » Fri Mar 04, 2016 2:31 pm

Markus Schwarz wrote:
neufer wrote:
It probably also didn't help that the Moons of Jupiter basically follow Jupiter
but they were never in the same pattern from night to night.
Naively, I would have thought that a "star" that changed from night to night would have drawn the attention of ancient sky gazers. After all, that's how planets were recognised as a special type of "light in the night sky".
A lot of nearby 4th magnitude "stars" change their positions vis-a-vis Jupiter from night to night.

Re: APOD: Moons and Jupiter (2016 Mar 03)

by Markus Schwarz » Fri Mar 04, 2016 10:31 am

neufer wrote:It probably also didn't help that the Moons of Jupiter basically follow Jupiter
but they were never in the same pattern from night to night.
Naively, I would have thought that a "star" that changed from night to night would have drawn the attention of ancient sky gazers. After all, that's how planets were recognised as a special type of "light in the night sky".

Re: APOD: Moons and Jupiter (2016 Mar 03)

by neufer » Thu Mar 03, 2016 4:25 pm

Chris Peterson wrote:
Markus Schwarz wrote:
Coil_Smoke wrote:
I have seen Jupiter and three of it's moons without a scope. I was quite amazed to spot those Jovian moons. Standing on my driveway on clear cold winter night, I wondered "Could one of Jupiter's moon really look to be that far away from it's planet?
" Then... " Those three objects are in a straight line with Jupiter, They must be moons. WOW "
I have bad eyes and have never directly seen the moons of Jupiter, but apparently persons with good eyes can. So, I wonder why no ancient astronomer ever noticed the four companions of Jupiter. (According to Wikipedia the Chinese astronomer Gan De did/might have spotted them in the 4th century BC.)
I expect that many people in ancient times saw them. And saw that Saturn doesn't appear round. And saw Uranus. What it comes down to isn't seeing these things, but recording the observations.
It probably also didn't help that the Moons of Jupiter basically follow Jupiter
but they were never in the same pattern from night to night.

Re: APOD: Moons and Jupiter (2016 Mar 03)

by Chris Peterson » Thu Mar 03, 2016 3:43 pm

Markus Schwarz wrote:
Coil_Smoke wrote:I have seen Jupiter and three of it's moons without a scope. I was quite amazed to spot those Jovian moons. Standing on my driveway on clear cold winter night, I wondered "Could one of Jupiter's moon really look to be that far away from it's planet?
" Then... " Those three objects are in a straight line with Jupiter, They must be moons. WOW "
I have bad eyes and have never directly seen the moons of Jupiter, but apparently persons with good eyes can. So, I wonder why no ancient astronomer ever noticed the four companions of Jupiter. (According to Wikipedia the Chinese astronomer Gan De did/might have spotted them in the 4th century BC.)
I expect that many people in ancient times saw them. And saw that Saturn doesn't appear round. And saw Uranus. What it comes down to isn't seeing these things, but recording the observations.

I've seen Jupiter's moons without aid many times. What I do is line myself up with a power or phone line so that it occludes Jupiter. Once that bright source is blocked, the moons are often easy to see.

Re: APOD: Moons and Jupiter (2016 Mar 03)

by JohnD » Thu Mar 03, 2016 2:55 pm

It's always puzzled me that while the face on the Moon is clear to me when I see it in the sky, that face is not visible on a photograph with any magnification. I know that other societies see other paradoelic images (Chinese rabbit) but ours is overpoweringly familiar, yet phantasmic.

JOhn

Re: APOD: Moons and Jupiter (2016 Mar 03)

by Markus Schwarz » Thu Mar 03, 2016 10:29 am

Coil_Smoke wrote:I have seen Jupiter and three of it's moons without a scope. I was quite amazed to spot those Jovian moons. Standing on my driveway on clear cold winter night, I wondered "Could one of Jupiter's moon really look to be that far away from it's planet?
" Then... " Those three objects are in a straight line with Jupiter, They must be moons. WOW "
I have bad eyes and have never directly seen the moons of Jupiter, but apparently persons with good eyes can. So, I wonder why no ancient astronomer ever noticed the four companions of Jupiter. (According to Wikipedia the Chinese astronomer Gan De did/might have spotted them in the 4th century BC.)

Re: APOD: Moons and Jupiter (2016 Mar 03)

by elipongo » Thu Mar 03, 2016 8:02 am

The linked to list of the solar system's largest moons says it was last updated in 2011. Don't we have better data now on the Pluto – Charon system since the New Horizons flyby?

Re: APOD: Moons and Jupiter (2016 Mar 03)

by Coil_Smoke » Thu Mar 03, 2016 5:39 am

I have seen Jupiter and three of it's moons without a scope. I was quite amazed to spot those Jovian moons. Standing on my driveway on clear cold winter night, I wondered "Could one of Jupiter's moon really look to be that far away from it's planet?
" Then... " Those three objects are in a straight line with Jupiter, They must be moons. WOW "

APOD: Moons and Jupiter (2016 Mar 03)

by APOD Robot » Thu Mar 03, 2016 5:09 am

Image Moons and Jupiter

Explanation: Some of the Solar System's largest moons rose together on February 23. On that night, a twilight pairing of a waning gibbous Moon and Jupiter was captured in this sharp telescopic field of view. The composite of short and long exposures reveals the familiar face of our fair planet's own large natural satellite, along with a line up of the ruling gas giant's four Galilean moons. Left to right, the tiny pinpricks of light are Callisto, Io, Ganymede, [Jupiter], and Europa. Closer and brighter, our own natural satellite appears to loom large. But Callisto, Io, and Ganymede are actually larger than Earth's Moon, while water world Europa is only slightly smaller. In fact, of the Solar System's six largest planetary satellites, only Saturn's moon Titan is missing from the scene.

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