What are these trails?

[gnomus]

I had one frame last night with perfectly parallel trails in it.  I don't think these are planes.  Could these be satellites?  If so, which ones might travel in tandem like this?

[Davey-T]

Lots about, you can load them into Stellarium to see which ones they are.

Dave

[xtreemchaos]

thay look like satellites if thay where a plane you would pick the nav lights up aswell .clear skys  charl.

[michael.h.f.wilkinson]

Almost certainly satellites. Some travel in formation, others form parallel tracks more-or-less by chance

[Pompey Monkey]

They might be several thousand miles apart. Clue: How long were your subs?

PS Was that taken with your Atik or Canon?

[laudropb]

Nice image. Look like satellites to me.

[gnomus]

They might be several thousand miles apart. Clue: How long were your subs?

PS Was that taken with your Atik or Canon?

5 minute subs. The Atik.

[jambouk]

Satellites. What software are you using to stack? I think sigma-clipping in DSS will remove them.

If you know the exact date and time in UTC, you could use Heavens above to work out what satellites they were.

James

[ronin]

NOSS satellites I suspect. They are tethered tandem or triplet satellites (US or Chinese) so would give the tracks seen and people often see the satellites as 2's or 3's and then the cry of UFO's goes out as they travel in formation.

[gnomus]

NOSS satellites I suspect. They are tethered tandem or triplet satellites (US or Chinese) so would give the tracks seen and people often see the satellites as 2's or 3's and then the cry of UFO's goes out as they travel in formation.

I didn't cry 'UFO', it was more 'What are they?' When I get a chance I will check the timing of the sub and see if I can work out what they were.

[StargeezerTim]

Train Tracks... clear as night...

[gnomus]

Satellites. What software are you using to stack? I think sigma-clipping in DSS will remove them.

If you know the exact date and time in UTC, you could use Heavens above to work out what satellites they were.

James

I marked it as 'Bad' and took another frame, but PixInsight was able to remove the trails.

[ollypenrice]

I marked it as 'Bad' and took another frame, but PixInsight was able to remove the trails.

Don't throw them away. Sigma stacking will take them out if you have a decent number of others. Maybe 7 or 8. People say 10/12 but in Astro Art you don't need that many when stacking. AstroArt also has a 'remove line' cosmetic funcion which would kill these. I often wonder why more people don't use it. Our guests see me stacking in AA and often buy it n the spot. It's pretty good.

Olly

[gnomus]

Don't throw them away. Sigma stacking will take them out if you have a decent number of others. Maybe 7 or 8. People say 10/12 but in Astro Art you don't need that many when stacking. AstroArt also has a 'remove line' cosmetic funcion which would kill these. I often wonder why more people don't use it. Our guests see me stacking in AA and often buy it n the spot. It's pretty good.

Olly

Yes I probably wasn't clear. I took 10 x 5 mins in each channel using SGP. When I saw this one come up I marked it as 'Bad' in SGP, and this then offered me the chance to take an additional frame (so I would have 10 good ones). But when it came to processing I thought I'd give it a go in PI using sigma clipping. Turned out there was no trace of the trails, so my blue channel consisted of 11 frames. I'm quite impressed that they were removed by PI given how dramatic they are.

I'll look at AA, but I've spent quite enough already this month, and it's only the 8th!

[gnomus]

Well, I've not been able to identify both these satellites.  According to my Fits header the image was captured at 23:26:17 UTC on 7 September 2015.  I assume that the time given is the end of capture time.  The exposure was 5 minutes duration, so that gives us a window back to just after 23:21.  

Having got the Stellarium plugin working, it does show a satellite called Iridium 22 passing close to M31 at 23:22:22 UTC.   The direction of travel shown in Stellarium would take this satellite slightly closer to M110 after it passes M31, and this fits with what is in the image.  As to the second satellite, nothing else is shown in Stellarium.

I registered with "Heavens Above", but, probably due to my own ineptitude, I could find no way of interrogating the site to get the information I was after.