by johnnydeep » Sun Apr 21, 2024 5:51 pm
Chris Peterson wrote: ↑Sun Apr 21, 2024 3:46 am
johnnydeep wrote: ↑Sat Apr 20, 2024 7:20 pm
wrightdobbs wrote: ↑Sat Apr 20, 2024 6:19 pm
Hey there, I'm the author of this composite. These images were captured with my lens on a star tracker in Arkansas. The camera was not level at the time of the exposures because I didn't make any adjustments to the camera during tracking by adjusting where the camera was on the right ascension axis. The angle of the features is not meant to exactly match reality, but I did my best to not rotate any of the images when compositing them together, but some small adjustments were made. That might be why the alignment isn't exactly perfect. However, the goal of this image wasn't really attempting to get this composite astronomically correct, more just show the two diamond rings, roughly on opposite sides of the solar disc, combined with a HDR version of totality. Hope that helps clear some things up, Johnny. Additionally, the angle of the features in this composite are not meant to show the celestial bodies apparent motion through the sky, it's just what I thought was the better angle to not put any diamond rings smack in the middle of a coronal streamer.
Thanks for the further explanation, but I still don't understand why the two diamonds wouldn't be on the path of the Moon across the Sun, or at least close to it, allowing for a little tweaking. Not "exactly matching reality" is one thing, but this difference in the locations of the diamonds seem way more than not "exactly". What did it actually look like in reality for someone watching (or filming) at the time? [ Not that I
still don't understand how Chris' reply above helps to explain my (apparent) misconception any better! ]
So I posted this animation on another thread, but I'll do it again because it's very relevant here. Note how much larger the Moon is than the Sun (which is why this was a long duration eclipse). Now I was only 100 meters from the center, so in this image the centers of the two bodies do cross. But imagine you were far off the centerline. The Moon and Sun would be offset, so the contact points wouldn't lie across a diameter. Now throw in the fact that the Moon isn't a circle, but has a jagged, mountainous edge, and maybe some field rotation... lots of things combine to explain why you might not see those contact points where you expect them.
_
prom_stack_anim2.gif
Thanks. But to me that short clip looks like it should still show any "diamonds" on the travel path, and not (significantly) off it.
But here's a great - interactive! - animation of how the eclipse would look from Greers Ferry AK, which I think is where the APOD image author took it from. It's on the path of totality:
https://www.timeanddate.com/eclipse/in/ ... o=20240408
But I'll note that the path of the Moon is decidedly curved, which also surprised me. I still have a hard time visualizing these astronomical events, and the close those events are to Earth, the harder it seems to be!
And this animation also seems to show that any diamonds would be on symmetrically opposite sides of the Sun's (and Moon's) disk. True though, it is only an animation and not the real thing.
[quote="Chris Peterson" post_id=338471 time=1713671195 user_id=117706]
[quote=johnnydeep post_id=338465 time=1713640840 user_id=132061]
[quote=wrightdobbs post_id=338463 time=1713637173 user_id=146342]
Hey there, I'm the author of this composite. These images were captured with my lens on a star tracker in Arkansas. The camera was not level at the time of the exposures because I didn't make any adjustments to the camera during tracking by adjusting where the camera was on the right ascension axis. The angle of the features is not meant to exactly match reality, but I did my best to not rotate any of the images when compositing them together, but some small adjustments were made. That might be why the alignment isn't exactly perfect. However, the goal of this image wasn't really attempting to get this composite astronomically correct, more just show the two diamond rings, roughly on opposite sides of the solar disc, combined with a HDR version of totality. Hope that helps clear some things up, Johnny. Additionally, the angle of the features in this composite are not meant to show the celestial bodies apparent motion through the sky, it's just what I thought was the better angle to not put any diamond rings smack in the middle of a coronal streamer.
[/quote]
Thanks for the further explanation, but I still don't understand why the two diamonds wouldn't be on the path of the Moon across the Sun, or at least close to it, allowing for a little tweaking. Not "exactly matching reality" is one thing, but this difference in the locations of the diamonds seem way more than not "exactly". What did it actually look like in reality for someone watching (or filming) at the time? [ Not that I [b][i]still [/i][/b]don't understand how Chris' reply above helps to explain my (apparent) misconception any better! ]
[/quote]
So I posted this animation on another thread, but I'll do it again because it's very relevant here. Note how much larger the Moon is than the Sun (which is why this was a long duration eclipse). Now I was only 100 meters from the center, so in this image the centers of the two bodies do cross. But imagine you were far off the centerline. The Moon and Sun would be offset, so the contact points wouldn't lie across a diameter. Now throw in the fact that the Moon isn't a circle, but has a jagged, mountainous edge, and maybe some field rotation... lots of things combine to explain why you might not see those contact points where you expect them.
_
prom_stack_anim2.gif
[/quote]
Thanks. But to me that short clip looks like it should still show any "diamonds" on the travel path, and not (significantly) off it.
But here's a great - interactive! - animation of how the eclipse would look from Greers Ferry AK, which I think is where the APOD image author took it from. It's on the path of totality:
https://www.timeanddate.com/eclipse/in/@4113167?iso=20240408
But I'll note that the path of the Moon is decidedly curved, which also surprised me. I still have a hard time visualizing these astronomical events, and the close those events are to Earth, the harder it seems to be!
And this animation also seems to show that any diamonds would be on symmetrically opposite sides of the Sun's (and Moon's) disk. True though, it is only an animation and not the real thing.