Moving White Dot in Night Sky
- Thread starter johne1618
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johne1618
Active Member
When I frame step through the video I frequently have to step through quite a few frames before the dot jumps from one location to another.
What causes this effect?
If the object was simply travelling fast I would expect it to jump forward every time I stepped the frame forward.
Just a difference in frame rates. The video you uploaded is 30 fps. The original must have been something like 24.
Gary McH-P
Member
As Mick suggested it’s the irregular path of an insect. The flight does not have to be a constant moving path, as the insect can hover and hold its position before moving off again. So the path is random rather than exponential In flight versus distance.
MclachlanM
Active Member
Here is the playback info in VLC:
The video is playing at 30fps but as you can see this doesn't match the actual fps of the video, VLC seems to think that the actual frame rate is around 5fps which is why you need to skip through 4-6 frames in the playback to see one frame of the video change. Perhaps it has been slowed down at some point?
johne1618
Active Member
Would an insect close to the camera be illuminated at night?
johne1618
Active Member
I don’t know much more about the livestream though it might be a NASA official source.
A week ago someone else recorded a similar object on the livestream traveling on a similar trajectory.
If these objects are insects then they must be quite large insects to show up so well on the video. But a large insect like a moth wouldn’t fly so fast or so smoothly between changes of direction as the object in the twitter video.
Source: https://twitter.com/awakeningman/status/1426779107052851206?s=21
Last edited:
Mendel
Senior Member.
I have done theater lighting, and you learn quickly that you can't see how well a given volume of air is lit. You can have every inch of the stage floor brightly lit, and still have an actor stand in the shadows on that very stage. (Stage magicians employ this effect to make big things disappear.) Conversely, you can have a camera pointed at something dark, and still have the air in front of the camera be very well lit. (Maybe you've seen flash photography at night: the subjects close to the camera are well lit, while the background is still dark.)
We get the illusion that everything is dark because we don't see any light, but you can't really see light when you're looking at it sideways. (This is why laser traps in heist movies etc. used to need smoke or fog to make them visible- nowadays they're just CGI, of course.) So you can have a brightly lit volume of air in front of the camera that you can't see, but any insect or bat that flies through that is still going to be well lit.
(Another example is brightly lit satellites on a dark night sky, or even the moon. It's hard to intuitively grasp that the moon is in bright sunlight when the whole night sky looks so dark.)
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