Strange Squiggly line in frames

[LooseFur]

Hi all,

A quick question - I am sure someone here has seen this before, but what is it?
In about 10 frames (of 100+) I see the below 'squiggly line'. What on earth (or space!) is it?

It clearly moves from the top of 1 frame to the bottom of tenth (ish) frame. I assume it's not an aircraft? Drink flying?

 

Thanks

 

[Tomatobro]

try "heavens above" to search for satellite

[LooseFur]

25 minutes ago, Tomatobro said:

try "heavens above" to search for satellite

Thanks, I'll have a look. Strange that it's so wobbly though - I thought satellite trajectories were quite linear/straight. But I am not expert by any means!

[tooth_dr]

59 minutes ago, LooseFur said:

Thanks, I'll have a look. Strange that it's so wobbly though - I thought satellite trajectories were quite linear/straight. But I am not expert by any means!

It could be a satellite but with some vibration/movement with the telescope during capture, so it’s recorded as oscillating.

[JamesF]

Aircraft trails can look a bit like that sometimes, in my experience.  The apparent "wobble" might be lights flashing on each wing.  Not certain it's that, but neither would it surprise me if it were.

James

[LooseFur]

42 minutes ago, tooth_dr said:

It could be a satellite but with some vibration/movement with the telescope during capture, so it’s recorded as oscillating.

I too was suspecting camera shake actually, but on closer inspection - the stars themselves do appear sharp (at least to me, see below - a different frame with the line near some stars) . Shutter speed was 1/10th of a second

[Tomatobro]

There are some websites that show pictures of tumbling space junk or other stuff.  That's moved quite a distance for a tenth of a second and you say the other frames show the object moving in a straight line frame to frame. You are right though in thinking that usually sats produce straight lines on the frame.

I wonder if it appeared mid frame and disappeared the same way. Could be interesting to stack just those frames to see what it looked like

 

[LooseFur]

15 minutes ago, Tomatobro said:

There are some websites that show pictures of tumbling space junk or other stuff.  That's moved quite a distance for a tenth of a second and you say the other frames show the object moving in a straight line frame to frame. You are right though in thinking that usually sats produce straight lines on the frame.

I wonder if it appeared mid frame and disappeared the same way. Could be interesting to stack just those frames to see what it looked like

 

yep, it moves in a straight line, frame to frame but always 'squiggly' like that. Similar shape each time too.

[LooseFur]

I did a quick stack, using only the frames with the line in it - it's very noisy actually and it has a lot of what I think you guys call 'walking noise'? PS I did no dithering, this was taken on a fixed tripod (no tracking/guiding). I was just experimenting with a 200mm lens I have.

Edited August 6, 2020 by LooseFur

[tooth_dr]

47 minutes ago, LooseFur said:

I did a quick stack, using only the frames with the line in it - it's very noisy actually and it has a lot of what I think you guys call 'walking noise'? PS I did no dithering, this was taken on a fixed tripod (no tracking/guiding). I was just experimenting with a 200mm lens I have.

It could be a tumbling satellite.  I did recently experience this and my stars also looked ok, but it was concluded that it was the wind shaking the scope.  The stars appears slightly elongated in line with the oscillations, so perhaps it is shake?  The mirror clicking up might cause this?

[LooseFur]

7 minutes ago, tooth_dr said:

It could be a tumbling satellite.  I did recently experience this and my stars also looked ok, but it was concluded that it was the wind shaking the scope.  The stars appears slightly elongated in line with the oscillations, so perhaps it is shake?  The mirror clicking up might cause this?

maybe you are right. I was using 'quiet continuous' drive mode on my nikon d810, which I had _thought_ locked the mirror the up prior to exposure. Maybe I am  wrong. Strange, though - because other images using the quiet mode show satellite trails as straight lines. Puzzling, but interesing! See below:

Edited August 6, 2020 by LooseFur

[tooth_dr]

Just now, LooseFur said:

maybe you are right. I was using 'quiet continuous' drive mode on my nikon d810, which I had _thought_ locked the mirror the up prior to exposure. Maybe I am  wrong. Strange, though - because other images using the quiet mode show satellite trails as straight lines. Puzzling, but interesing!

I was wondering if it was possible to do mirror lock up.  I have a nikon d800e and havent worked it out yet. 

[LooseFur]

23 minutes ago, tooth_dr said:

I was wondering if it was possible to do mirror lock up.  I have a nikon d800e and havent worked it out yet. 

It could be that actually, using the quiet mode DOES lock the mirror up but there is still vibration from the shutter mechanism itself (hence the Electronic Front Curtain feature, only engaged in Mup drive mode). But I am still confused why the satellite trail in the above image doesn't 'wobble'.

[tooth_dr]

22 minutes ago, LooseFur said:

But I am still confused why the satellite trail in the above image doesn't 'wobble'.

I wouldn't be sure but an educated guess, because it's at right angles to movement of the shutter (or whatever is causing vibration), so the vibrations are longtitudinal relative to the satellite movement (rather than tranverse as in the top photo)?

[The Admiral]

3 hours ago, LooseFur said:

I too was suspecting camera shake actually, but on closer inspection - the stars themselves do appear sharp (at least to me, see below - a different frame with the line near some stars) . Shutter speed was 1/10th of a second

I really wouldn't like to say, but it's interesting that there is colour associated with it, with a light green on the right 'bump' and magenta on the left 'bump', with white in between:

I would just make the comment that aircraft navigation lights are red on the left of the aircraft and green on the right and white at the rear. Quite often than these are strobed. I'm not sure that this explains the sequence of colours though, unless perhaps the left and right lights are strobed alternately, but it is food for thought.

Ian

[LooseFur]

48 minutes ago, The Admiral said:

I really wouldn't like to say, but it's interesting that there is colour associated with it, with a light green on the right 'bump' and magenta on the left 'bump', with white in between:

I would just make the comment that aircraft navigation lights are red on the left of the aircraft and green on the right and white at the rear. Quite often than these are strobed. I'm not sure that this explains the sequence of colours though, unless perhaps the left and right lights are strobed alternately, but it is food for thought.

Ian

Yes, I noticed the colour too. I thought perhaps it was some mild chromatic aberration or colour fringing. It's very odd. I am not stressed about it, I am curious however.

[LooseFur]

I think I know what it is, I think my suspicion was correct - it's shutter shock (not mirror slap shock). Electronic Front Curtain only works in Mirror up mode on the D810 - not on the quiet modes (although the mirror is indeed raised in this mode). 

Edited August 6, 2020 by LooseFur

[tooth_dr]

2 hours ago, LooseFur said:

I think I know what it is, I think my suspicion was correct - it's shutter shock (not mirror slap shock). Electronic Front Curtain only works in Mirror up mode on the D810 - not on the quiet modes (although the mirror is indeed raised in this mode). 

I thought it was something to do with the camera 👌🏻, at least you have worked out the exact cause 👍🏼