by Chris Peterson » Fri Nov 06, 2020 9:49 pm
MarkBour wrote: ↑Fri Nov 06, 2020 7:27 pm
Chris Peterson wrote: ↑Fri Nov 06, 2020 2:15 pm
BDanielMayfield wrote: ↑Fri Nov 06, 2020 5:39 am
Interesting geometry here. We’re seeing an unlit side of ISS in front of a sunlit part of the Moon. ISS must have been inside the Earth’s shadow at the time.
The Moon just three days past full, and imaged near midnight. No way that the ISS could be anywhere else than in shadow.
So, would that mean that the photographer had no way to track the ISS visually as it approached conjunction with the Moon? Would Derek Demeter have just aimed the shot and used sufficiently precise data from some source to know when this event would happen? Would he have had to have known this down to a matter of seconds? Maybe a series of shots were taken in rapid fire around the moment of the transit? The high resolution image is wonderfully detailed in its rendering of the space station shape, I guess as you are both saying, there's no light bouncing off of it, it's all a silhouette!
Right, I don't think it would be visible. But the orbit is very well characterized, so capturing it blind shouldn't be a big deal with an accurate time source (like GPS). I posted a
capture I made earlier this year. This was around sunset, and moonrise, so the ISS was much farther away than in today's image. But you can clearly see what it looks like in front of the Moon when it is in sunlight. Brighter than the Moon surface, in fact.
_
[quote=MarkBour post_id=307844 time=1604690838 user_id=141361]
[quote="Chris Peterson" post_id=307841 time=1604672147 user_id=117706]
[quote=BDanielMayfield post_id=307835 time=1604641152 user_id=139536]
Interesting geometry here. We’re seeing an unlit side of ISS in front of a sunlit part of the Moon. ISS must have been inside the Earth’s shadow at the time.
[/quote]
The Moon just three days past full, and imaged near midnight. No way that the ISS could be anywhere else than in shadow.
[/quote]
So, would that mean that the photographer had no way to track the ISS visually as it approached conjunction with the Moon? Would Derek Demeter have just aimed the shot and used sufficiently precise data from some source to know when this event would happen? Would he have had to have known this down to a matter of seconds? Maybe a series of shots were taken in rapid fire around the moment of the transit? The high resolution image is wonderfully detailed in its rendering of the space station shape, I guess as you are both saying, there's no light bouncing off of it, it's all a silhouette!
[/quote]
Right, I don't think it would be visible. But the orbit is very well characterized, so capturing it blind shouldn't be a big deal with an accurate time source (like GPS). I posted a [url=http://www.cloudbait.com/20200604_iss-moon.php]capture I made earlier this year[/url]. This was around sunset, and moonrise, so the ISS was much farther away than in today's image. But you can clearly see what it looks like in front of the Moon when it is in sunlight. Brighter than the Moon surface, in fact.
_
[attachment=0]20200604_stack.jpg[/attachment]