Starship Asterisk*

by **orin stepanek** » Thu Mar 16, 2023 10:36 pm

Idon't know if other worlds have views like this one' but i'll be happy
if they do!

Pretty kitty!

by **johnnydeep** » Thu Mar 16, 2023 8:17 pm

Chris Peterson wrote: ↑Thu Mar 16, 2023 5:14 pm
johnnydeep wrote: ↑Thu Mar 16, 2023 3:35 pm
Chris Peterson wrote: ↑Wed Mar 15, 2023 9:32 pm
The two images were taken about a day apart. And both are framed such that the planets are aligned horizontally, not so the local horizon is horizontal.
"Yeah, but..." I can't figure out how the one gets transformed into the other. Hmm. I suppose if the Jupiter-Venus line was rotated clockwise about 90 degrees around Jupiter as the pivot, that would do it. Is that essentially what's happening over the course of a day due to relative motions of the two planets?

angles of jupiter moon plane and line to venus.png
Horizon (red line) based view from my location on March 1 (about when the second image was taken) and March 2 (when my image was taken) with the orientation of the moons shown, as well.
_

conj.png

Thanks! That makes it much clearer for me. I take it Venus was the planet doing most of the moving over that single (Earth) day.

by **Chris Peterson** » Thu Mar 16, 2023 5:14 pm

johnnydeep wrote: ↑Thu Mar 16, 2023 3:35 pm
Chris Peterson wrote: ↑Wed Mar 15, 2023 9:32 pm
johnnydeep wrote: ↑Wed Mar 15, 2023 9:02 pm Hmm, why is the angle of the orbital plane of Jupiter's moons so different from the line between Jupiter and Venus in Chris' image compared to Bird_Man's image? Being tilted toward or away I could see being caused by Jupiter and Venus passing each other, but in both images the planets are on the same sides.
The two images were taken about a day apart. And both are framed such that the planets are aligned horizontally, not so the local horizon is horizontal.
"Yeah, but..." I can't figure out how the one gets transformed into the other. Hmm. I suppose if the Jupiter-Venus line was rotated clockwise about 90 degrees around Jupiter as the pivot, that would do it. Is that essentially what's happening over the course of a day due to relative motions of the two planets?

angles of jupiter moon plane and line to venus.png

Horizon (red line) based view from my location on March 1 (about when the second image was taken) and March 2 (when my image was taken) with the orientation of the moons shown, as well.
_

by **johnnydeep** » Thu Mar 16, 2023 3:35 pm

Chris Peterson wrote: ↑Wed Mar 15, 2023 9:32 pm
johnnydeep wrote: ↑Wed Mar 15, 2023 9:02 pm Hmm, why is the angle of the orbital plane of Jupiter's moons so different from the line between Jupiter and Venus in Chris' image compared to Bird_Man's image? Being tilted toward or away I could see being caused by Jupiter and Venus passing each other, but in both images the planets are on the same sides.
The two images were taken about a day apart. And both are framed such that the planets are aligned horizontally, not so the local horizon is horizontal.

"Yeah, but..." I can't figure out how the one gets transformed into the other. Hmm. I suppose if the Jupiter-Venus line was rotated clockwise about 90 degrees around Jupiter as the pivot, that would do it. Is that essentially what's happening over the course of a day due to relative motions of the two planets?

by **Chris Peterson** » Wed Mar 15, 2023 9:32 pm

johnnydeep wrote: ↑Wed Mar 15, 2023 9:02 pm Hmm, why is the angle of the orbital plane of Jupiter's moons so different from the line between Jupiter and Venus in Chris' image compared to Bird_Man's image? Being tilted toward or away I could see being caused by Jupiter and Venus passing each other, but in both images the planets are on the same sides.

The two images were taken about a day apart. And both are framed such that the planets are aligned horizontally, not so the local horizon is horizontal.

by **johnnydeep** » Wed Mar 15, 2023 9:02 pm

Hmm, why is the angle of the orbital plane of Jupiter's moons so different from the line between Jupiter and Venus in Chris' image compared to Bird_Man's image? Being tilted toward or away I could see being caused by Jupiter and Venus passing each other, but in both images the planets are on the same sides.

by **Bird_Man** » Wed Mar 15, 2023 7:41 pm

Here is an image I captured of Jupiter and Venus. You can see three of Jupiter's moons. To get the moons to show I did have to over expose the planets, making them appear larger than they are.

by **Chris Peterson** » Wed Mar 15, 2023 5:40 pm

Fred the Cat wrote: ↑Wed Mar 15, 2023 4:35 pm I'm a little dissapointed there were no submissions where you could clearly see Jupiter's moon in conjuction with its proximity to Venus. Are there technical reasons for this or just nobody submitted a such an image? :?

Well, I posted this a few days ago in another conjunction APOD. It helps demonstrate the problem- this is essentially an HDR image exposed separately for the sky, the planets, and the moons. Even here, the planets are processed such that they are overexposed and larger than their actual sizes. In widefield astronomical landscape pictures like today's APOD, with a light sky background, there just isn't enough dynamic range to capture the scene and the moons. It's not impossible, but it would require careful HDR processing, and the moons would be very close together and close to Jupiter given such a wide FOV (my image has a FOV of just over a degree. Today's image is more like 30°.)
_

by **Fred the Cat** » Wed Mar 15, 2023 4:35 pm

I'm a little dissapointed there were no submissions where you could clearly see Jupiter's moon in conjuction with its proximity to Venus. Are there technical reasons for this or just nobody submitted a such an image?

by **APOD Robot** » Wed Mar 15, 2023 4:06 am

Jupiter and Venus Converge over Germany

Explanation: This was a sky to show the kids. Early this month the two brightest planets in the night sky, Jupiter and Venus, appeared to converge. At their closest, the two planets were separated by only about the angular width of the full moon. The spectacle occurred just after sunset and was seen and photographed all across planet Earth. The displayed image was taken near to the time of closest approach from Wiltingen, Germany, and features the astrophotographer, spouse, and their two children. Of course, Venus remains much closer to both the Sun and the Earth than Jupiter -- the apparent closeness between the planets in the sky of Earth was only angular. Jupiter and Venus have passed and now appear increasingly far apart. Similar planetary convergence opportunities will eventually arise. In a few months, for example, Mars and Venus will appear to congregate just as the Sun sets.

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