| Did I capture an airplane or the start of an alien invasion? | |
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| Airplane(s) | |
| Alien Invasion | |
| Neither | |
| Stop eating mushrooms when you're doing astrophotography in the forest. | |
| Login to vote and view results. |
3.31
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Hi Folks, I was imaging remotely at a dark site about 30 minutes from my house. When I started processing the results, I noticed a single frame that had the strangest pattern that I can't quite figure out. The target is the Iris Nebula, and just about at the center of the frame there are star trails in concentric circles that almost look like the shot was taken at the pole. Except... it's obviously not the pole, and there are other weird things going on like what looks to be a plane or satellite coming into the frame and then curving with the other trails. There's also some curves, like in the top left, that don't seem to be on the same circular plane as the central trails. There's also what clearly looks like a standard satellite bombing through in a strait line on the left. Here's the single 180" shot with the trails, neither of the subs on either side of this sub had any aberrations:  I also have an all-sky camera set up at my house that captured what surely must be an airplane circling overhead about 4 hours before the above photo was taken. Here's a video of that. Forgive the trees, I live in a literal forest: allsky-20220901.mov I removed this sub when I processed the final image from that night, but eventually I couldn't help myself and added the "UFO" photobomb into the final result:  Any thoughts on what this is? I wasn't anywhere near an airport, but it's got to be a plane circling, right? But if you look closely at the first photos, there are TONS of circular trails... all within just 180 seconds.Thanks for looking, and CS! -Kelly |
1.81
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| It looks like you have started a sub, and for some reason the mount has slewed back to Polaris - ie gone to home half way through a sub. So gone back to home, finished in the Dec axis, and then spent a little time finishing the home in the RA axis... my best guess. Nice bit of comedy on the poll :-) |
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Most aircraft will have multiple sets of lights distinguishable if they are low enough here is an extreme example: |
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ok, I give it a try, I like puzzles. To me this looks like two or even more images superimposed. We see different signals/patterns - star field and nebula - satellite trails - arcs The star field and satellite trails are clearly understood, what is puzzling is the arcs showing. The fact the the brightest arc is connecting to a satellite trail is coincidence. The arcs end in a star. This indicates that the camera moved for some time and then stopped but continued to gather light. The arcs seem to be concentric with the center in the center of the image. This is no concidence but indicates that some sort of rotation of the camera is causing this. The chances that something that is creating these arcs is effecting this in a way that it shows up centered in your image are next to zero. That means the explanation has to be that a rotation of your camera is creating these. So my verdict is: this is a prank. Likely a test of your new rotator. How am I doing ? Cheers Gernot |
4.07
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| The camera rotated for some reason. |
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3.31
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So my verdict is: this is a prank. Ha! Thanks, Gernot. Definitely not a prank. But your and others' seeing clear camera rotation had me doing some further investigation. This was from a session a few weeks ago. I distinctly remember seeing this sub when I was doing my "Blink" inspection and thinking it was too interesting of an aberration to just throw out. So I put it into a different folder. My memory was that it was from the middle of the session and that each sub on either side of this one looked fine. I had also checked the video from my all-sky and saw those circular over-flights in there, which seemed to confirm my initial thought that it was aircraft. My memory was not correct, however. Looking at the timestamp on the photo, it was from the very *end* of the session, right at 5am, right when my software tells my mount to autopark. At the NCP. So... I guess this is finishing the shot at the pole? It still doesn't seem to explain why all the stars except the ones with trails seem to mostly look fine. I suppose the Iris is pretty close to the pole, so maybe the jump was quick enough not to mess things up too much. But, yeah, this must be the mount slewing in RA then Dec as it heads for home. Usually with this mount (CEM26) they move in tandem, but I have seen it do one at a time when parking depending on starting position. In any event, thanks for looking. I thought it was a weird artifact worth sharing. Added with the video from the all-sky, makes for a good UFO story to start off the fall season. May alien joyrides (or broadband satellites launched from one apparently living here among us) steer clear of your subs. CS! -k |
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It looks like you have started a sub, and for some reason the mount has slewed back to Polaris - ie gone to home half way through a sub. So gone back to home, finished in the Dec axis, and then spent a little time finishing the home in the RA axis... my best guess. Nice bit of comedy on the poll :-) Yep. I think you nailed it! Thanks, -k |
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Hi Kelly, I don't mind a prank if it is fun for all  .But to be more serious, I still think it could be a superposition of two images. If you look at the stars at the end of the arcs it is apparent that these stars do not belong there within the context of the image. You can create an annotated image with PI and it will give you the names of all the (larger) stars. The ones at the end of the arc are not given, because they don't belong there.  So it really looks like two images in one. Could it be that the software with which you captured the images caused this ? CS Gernot |
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Looks like it's been solved. Referring to the question though, my answer would be "nothing on earth, it's outer space". Sorry couldn't resist.  |
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I also think your mount slewed back to home position before the frame was finished, moved in dec first and then in RA. the bright arc is Polaris, the smaller ones are the other stars surrounding the northern celestial pole.It still doesn't seem to explain why all the stars except the ones with trails seem to mostly look fine. I guess the other stars look fine because compared to polaris and some of the brighter stars ath the NCP they are so tiny they won't be registered once the mount is moving because their signal gets spread too much on the sensor. I guess Dec movement was pretty quick, since only in the trail of polaris you can properly see it. RA was slow enough for the smaller stars to leave a trail. |
