Starship Asterisk*

Jupiter and the Moons

Explanation: After sunset on October 3, some of the Solar System's largest moons stood low along the western horizon with the largest planet. Just after nightfall, a pairing of the Moon approaching first quarter phase and Jupiter was captured in this telephoto field of view. A blend of short and long exposures, it reveals the familiar face of our fair planet's own large natural satellite in stark sunlight and faint earthshine. At lower right are the ruling gas giant and its four Galilean moons. Left to right, the tiny pinpricks of light are Ganymede, [Jupiter], Io, Europa, and Callisto. Our own natural satellite appears to loom large because it's close, but Ganymede, Io, and Callisto are actually larger than Earth's Moon. Water world Europa is only slightly smaller. Of the Solar System's six largest planetary satellites, only Saturn's moon Titan, is missing from this scene. But be sure to check for large moons in your sky tonight.

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I like it!

Have photos of all six large moons in the same frame been taken?

BDanielMayfield wrote: ↑Sat Oct 05, 2019 2:15 pm
Have photos of all six large moons in the same frame been taken?

Probably...but since Titan is more than 10 times dimmer than Jupiter's large moons
it would require some processing to see them all at once.

What is that dot just to the right of the Moon, Saturn?

Psnarf wrote: ↑Sat Oct 05, 2019 3:30 pm
What is that dot just to the right of the Moon, Saturn?

• ξ Ophiuchi ?

The eye is superior to the emulsion, or digital camera equivalent, which is why this picture is "A blend of short and long exposures"
Could the eye have seen this, down the appropriate telescope to achieve the same magnification?

If not, then I submit, M'Luds, that this is another picture where art has conquered science.
John

JohnD wrote: ↑Sat Oct 05, 2019 4:19 pm The eye is superior to the emulsion, or digital camera equivalent, which is why this picture is "A blend of short and long exposures"
Could the eye have seen this, down the appropriate telescope to achieve the same magnification?

If not, then I submit, M'Luds, that this is another picture where art has conquered science.
John

The eye is significantly inferior to modern electronic sensors. It is lower resolution, it has poor optical quality, it has low quantum efficiency, and it has poor dynamic range. Do not confuse the ability of the eye with the ways that our visual processing system can make up for this, allowing our brains to construct an image that bears little resemblance to what is on the retina itself.

In short, you could not see an image like this with your eye, except by moving your eye around between the different parts and letting your brain paint a larger image. But this image captures rather well how you would perceive this scene through a small telescope (like a pair of binoculars). Eye or camera, either requires post processing to produce a realistic image.

Beautiful. Too bad we are not allowed on Europa.

neufer wrote: ↑Sat Oct 05, 2019 4:14 pm

Psnarf wrote: ↑Sat Oct 05, 2019 3:30 pm
What is that dot just to the right of the Moon, Saturn?

• ξ Ophiuchi ?

An ID for the brightest star (mag~7) to the right if the moon is HIP 84198. 4th magnitude ξ Oph (Aggia) is about 1° beyond the upper left corner (1.5° from the moon).

The links to the discussion, the previous and next day are all the same as for the Oct 04 page