Polar Orbit Satellite?

[dr_gn]

All,

I've been trying star trail photograpy for the first time this week. This is a crop from one example:




You can see there's a dotted red/white line that's pretty much vertical, and passes close to Polaris.

I'm assuming it's a satellite in a polar orbit?

Does the red/white alternating colour indicate a specific one?

Is it actually a satellite at all, or is it just some obvious artefect or imaging effect that I've missed?

The image is a stack of about 75 20' exposures, with a couple of seconds or so between subsequent images. There appears to be a gap in the sequence near the top for some reason.

Cheers.

[Eric Mc]

Possibly a tumbling spent upper stage that is in a polar orbit. I spotted one a couple of weeks ago. It had a dimming/brightening period of around 8 seconds.

Nice picture.