Starship Asterisk*

[quote="Chris Peterson" post_id=326772 time=1666709094 user_id=117706]
[quote=johnnydeep post_id=326769 time=1666708305 user_id=132061]
[quote=daddyo post_id=326760 time=1666676176 user_id=142712]
Isn’t the apparent moon orbital tilting over time due to an alt/az scope mount vs equatorial?
[/quote]

Frankly, I'm just not understanding why we are seeing the axial tilt of Jupiter (along with the tilt of the moons' orbital planes) change over the course of this video. Isn't the axial tilt of Jupiter relative to the line of sight from the Earth always the same no matter where on Earth you are or when you happen to look? [ Note: I fully expect to be proven to be wrong here since my 3D software is obsolete and bug-riddled. ]
[/quote]

If you don't track Jupiter with a mount that unwinds Earth's rotation, this is what you get. Jupiter certainly doesn't maintain the same orientation with respect to the horizon as it moves across the sky!
[/quote]

Ok. Still having a hard time visualizing it though. But my line of sight claim is still correct, isn't it? That is, the line through Earth's center and Jupiter's center is always at the same angle to Jupiter's axial tilt? ...gah - No, that can't be right either, since if Jupiter's axial tilt was 90 degrees, sometimes it would be perpendicular to our line of sight, and sometimes parallel to it!

[quote=johnnydeep post_id=326769 time=1666708305 user_id=132061]
[quote=daddyo post_id=326760 time=1666676176 user_id=142712]
Isn’t the apparent moon orbital tilting over time due to an alt/az scope mount vs equatorial?
[/quote]

Frankly, I'm just not understanding why we are seeing the axial tilt of Jupiter (along with the tilt of the moons' orbital planes) change over the course of this video. Isn't the axial tilt of Jupiter relative to the line of sight from the Earth always the same no matter where on Earth you are or when you happen to look? [ Note: I fully expect to be proven to be wrong here since my 3D software is obsolete and bug-riddled. ]
[/quote]

If you don't track Jupiter with a mount that unwinds Earth's rotation, this is what you get. Jupiter certainly doesn't maintain the same orientation with respect to the horizon as it moves across the sky!

First time I've felt seasick viewing an APOD.

Great animation, though, I just like having the ecliptic horizontal-ish, or at least consistent.

[quote=daddyo post_id=326760 time=1666676176 user_id=142712]
Isn’t the apparent moon orbital tilting over time due to an alt/az scope mount vs equatorial?
[/quote]

Frankly, I'm just not understanding why we are seeing the axial tilt of Jupiter (along with the tilt of the moons' orbital planes) change over the course of this video. Isn't the axial tilt of Jupiter relative to the line of sight from the Earth always the same no matter where on Earth you are or when you happen to look? [ Note: I fully expect to be proven to be wrong here since my 3D software is obsolete and bug-riddled. ]

[attachment=1]220px-Jupiter_and_the_Galilean_Satellites.jpg[/attachment]
If Jupiter was a Star! We have Jupiter orbiting The sun and if it was
indeed a star; than we would have double star system! The Galilean
moons would be planets! 8-) Now, this makes me wonder that other
star systems may have planetary systems in similar fashion! :shock:
[attachment=0]c4ce0df8.png[/attachment]
Today's Kitty of The Day! :D

I like this video! :D

And I don't know about you, but I like seeing Jupiter's Great Red Spot looking so bright and orange. It doesn't always look like that!


[float=left][img3="Jupiter and its Great but wan-looking Not-So-Red Spot in 1979, photographed by Voyager 1. Image: NASA/JPL/USGS"]https://upload.wikimedia.org/wikipedia/commons/e/e2/Jupiter.jpg[/img3][/float][float=right][img3="Jupiter (and Europa) and Jupiter's Not-So-Great but deeply orange Red Spot in 2020, photographed by Hubble."]https://cdn.spacetelescope.org/archives/images/wallpaper1/heic2017a.jpg[/img3][/float]
[clear][/clear]


Once again I don't know about you, but I thought it was cool seeing Europa glide across the face of Jupiter, preceded by its black shadow like an evil twin! How suitable for Halloween! 😀 🎃 👻


[attachment=0]APOD 25 October 2022 image of Jupiter and moons from video.png[/attachment]


But where is the fourth Galilean moon, [url=https://upload.wikimedia.org/wikipedia/commons/e/e9/Callisto.jpg]Callisto[/url]? Okay, Callisto is in a wide orbit around Jupiter, so maybe Callisto strayed a bit far off and went to visit Mars, which has been shining so bright and ruddy in our night skies lately? And if Mars is too far away for Callisto (and it is), then maybe Callisto went to visit dwarf planet [url=https://upload.wikimedia.org/wikipedia/commons/thumb/b/be/PIA18920-Ceres-DwarfPlanet-20150219.jpg/1024px-PIA18920-Ceres-DwarfPlanet-20150219.jpg]Ceres[/url] in the asteroid belt?

Yes, that's probably it! So let's follow the sign so that we can find Ceres and Callisto!


[img3=""]https://plenty-lions.de/wp-content/uploads/2019/01/callisto_ceres.jpg[/img3]


But hey, what's this? The way to Ceres is "up" - yes, we know - but Callisto isn't up there? What's up? A Halloween ghost ate it up? :shock:

Ann

Isn’t the apparent moon orbital tilting over time due to an alt/az scope mount vs equatorial?

[url=https://apod.nasa.gov/apod/ap221025.html] [img]https://apod.nasa.gov/apod/calendar/S_221025.jpg[/img] [size=150]Jupiter Rotates as Moons Orbit[/size][/url]

[b] Explanation: [/b] Jupiter and its moons move like our Sun and its planets. Similarly, [url=https://solarsystem.nasa.gov/planets/jupiter/in-depth/]Jupiter[/url] spins while [url=https://en.wikipedia.org/wiki/Moons_of_Jupiter]its moons[/url] circle around. [url=https://apod.nasa.gov/apod/ap211026.html]Jupiter’s rotation[/url] can be observed by tracking circulating [url=https://en.wikipedia.org/wiki/Atmosphere_of_Jupiter#/media/File:Jupiter_cloud_bands.svg]dark belts and light zones[/url]. The [url=https://www.nasa.gov/feature/goddard/jupiter-s-great-red-spot-a-swirling-mystery]Great Red Spot[/url], the largest storm known, rotates to become visible after about 15 seconds in the 48-second time lapse video. [url=https://youtu.be/8thpIjA8_VI]The video[/url] is a compilation of shorts taken over several nights last month and combined into a digital recreation of how 24-continuous hours would appear. [url=https://solarsystem.nasa.gov/moons/jupiter-moons/overview/]Jupiter's brightest moons[/url] always orbit in the plane of the planet's rotation, even as <a rhef="ap200701.html">Earth’s spin</a> makes the whole system appear to [url=https://apod.nasa.gov/apod/ap220911.html]tilt[/url]. The moons [url=https://solarsystem.nasa.gov/moons/jupiter-moons/europa/in-depth/]Europa[/url], [url=https://apod.nasa.gov/apod/ap211011.html]Ganymede[/url], and [url=https://apod.nasa.gov/apod/ap140330.html]Io[/url] are [url=https://livedoor.blogimg.jp/kijyo_ita/imgs/c/4/c4ce0df8.png]all visible[/url], with Europa's [url=https://apod.nasa.gov/apod/ap220427.html]shadow appearing[/url] as the icy [url=https://en.wikipedia.org/wiki/Galilean_moons]Galilean moon[/url] crosses Jupiter's disk. Jupiter remains [url=https://blogs.nasa.gov/Watch_the_Skies/2022/09/16/jupiter-to-reach-opposition-closet-approach-to-earth-in-70-years/]near opposition[/url] this month, meaning that it is unusually bright, near to its closest to the Earth, and visible nearly all night long.


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