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Who knows, what is this oscillating line/satellite trail?

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Who knows, what is this very odd oscillating satellite trail (if that's what it is)?
this was near Deer Lick Galaxy, at date and time shown (zoom up in 5min exposure), shot from Likely, CA:
thx
glen

 

 
2 years 8 months ago #73910
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hummmm that's prove Alien drinks too much ...
2 years 8 months ago #73911

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Hi Glen,

I think as the wobbly satellite trail comes together with slightly egg shaped stars means it is due to imperfections in your mount.

CS
Klaus
2 years 8 months ago #73912

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Are you guiding at a high sampling rate? With that scale, I wonder what the duration of each oscillation is?
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2 years 8 months ago #73921

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I had a similar trail on one of my exposures (of a different target) and it was a firework.... though I suspect closer than the one in your frame.... 

 
Last edit: 2 years 8 months ago by jiberjaber.
2 years 8 months ago #73941
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I have never seen a satellite trail that looked like that and it is unlikely since the amount of lateral movement would probably tear it apart. They usually appear as a single solid or dashed line.

Look for something much closer, such as a plane or balloon.

Paul
Last edit: 2 years 8 months ago by Paul.
2 years 8 months ago #73948

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I saw this  odd trail on 2 separate nights, near same Deer Lick Galaxy target.   It is not fireworks.   I too at first suspected a mount issue, combined with a probably slow moving satellite, but seems odd that I have never seen this kind of artifact before, if it is due to my mount. The star eccentricity is roughly orthogonal to trail, and by eyeball the magnitude of the eccentricity is 'in the ballpark' of the trail peak to trough amplitude.  So that supports the mount issue explanation. But if it is a mount issue, sort of odd that no one else has ever seen such an artifact (as far as I know), and I have numerous other satellite trails that are all straight (although they may be much faster moving satellites).  If the wiggle was due to mount, that sine wave wiggle would make star image somewhat bimodal; whether my stars show that is not so obvious(most don't seem to, some others are arguable). Also, I don't know the time periodicity of wiggle;I only know that exposure was 5min, that trail extends across the full image, so we only know that ~200 cycles(eyeball) occur in photo, and occur in less than 300sec, so cycle upper limit is ~1.5sec.  (My mount is an Ioptron CEM60.)   Also I just now noticed a fainter trail in the very same image (attached), and it does NOT exhibit the wiggle. (See bottom right corner faint trail.)   So if both satellites traveling at same angular speed, then issue unlikely to be the mount.  But may be the satellites were travelling at different speeds - I have no idea.     

...... and now as I am searching more, I found someone else reported something very similar in Cloudy Nights, on an Ioptron CEM70:   www.cloudynights.com/topic/773952-wobble-in-satellite-trail/
They seem to think it was an Ioptron issue.   I think I will have to do a more quantitative analysis(eg PSF) on my stars and my other images, to see if I agree.   
 
2 years 7 months ago #74034
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Sorry - try this image:
 
2 years 7 months ago #74035
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I do wonder if the simple sine oscillation is a tumbling satellite. If so, it being non-uniform in shape would catch sunlight in a repeating pattern. An example, consider a satellite with solar panels off each side. If it is spinning as it travels, then one side solar panel will catch the light and then the other.

The other thing I thought about is it could still be a mount issue. The stars in the attached image seem to be oblong in the same direction as the peaks of the sine wave. If the satellite travel was perpendicular to the error in the mount, it would show up the most vs the lower, fainter trail in the right corner, the fainter trail runs more parallel to the potential mount error. Parallel to the error would greatly reduce the magnitude of the error appearing in the trail as a much larger component of the oscillation is along the trail instead of perpendicular to it.

It seems too linear and uniform in pattern to be a firework I think.
2 years 7 months ago #74069

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Hi,

This is a tricky one but my guess is that the wobbly line is a geostationary (TV broadcast) satellite, the stars are moving but the satellite is not, and the cause of the line is wobbly is because of the guiding.

Br,
/Markku
2 years 7 months ago #74089

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The period seems too short to be periodic error. My guess is vibrations, possibly wind. Or maybe even a firefly
Last edit: 2 years 7 months ago by Andrew.
2 years 7 months ago #74151

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