46 replies to this topic

[fmeschia]

While processing some data taken earlier this year, I found a strange curved track on the rejection map for my L frames:

 

 

I then started blinking the individual frames, and I found the fast-moving object you can see in this video (also with better quality on YouTube at https://youtu.be/Q6butAuRhGY):

 

 

 

The first frame in the sequence was taken at 10:33 UTC, the last one at 12:24 UTC on 02/27/2025. The object moved over 20 arcminutes in a bit less than two hours. It’s way too slow to be an airplane or a satellite. For an asteroid, it would be fast but not impossibly fast, and the strong curvature suggests that it was close to Earth. But the Minor Planet Center doesn’t list any asteroid following that trajectory. I saw that the IM-2 lunar mission was launched earlier that day... could I have imaged the spacecraft during translunar coasting?

 

Thanks for any idea or suggestion!

[ngc7319_20]

Maybe geosynchronous satellite?

[fmeschia]

Maybe geosynchronous satellite?

No, it wouldn’t have any curvature. Also it’s way too slow: a geosync satellite would appear to move at 15 degrees/hour from the perspective of a telescope tracking the stars. This thing moves at roughly 10 arcminutes/hour.

Edited by fmeschia, 20 April 2025 - 12:48 PM.

[ngc7319_20]

Could it be a hot pixel on the sensor?  Without knowing more about the imaging equipment, image sequence, pointings, etc. it is hard to rule it in or out.

[fmeschia]

Could it be a hot pixel on the sensor?  Without knowing more about the imaging equipment, image sequence, pointings, etc. it is hard to rule it in or out.

I don’t think so. It covers more than 20-30 pixels, it moves in a consistent direction which is not correlated with my dithering.

[iamstickman]

It almost has the appearance of StarLink Satellite train. I see them all the time here in AZ.

 

https://katu.com/new...hington-pacific

[fmeschia]

It almost has the appearance of StarLink Satellite train. I see them all the time here in AZ.

 

https://katu.com/new...hington-pacific

Save for the fact that I’ve never seen Starlinks going anything but in a straight line.

[Pompey Monkey]

Could it be a satellite at one of the Lagrange points?

I'm not skilled enough do do the analysis, but maybe someone else on here might have a feel for it.

[JWolf_21]

My doubt is, which kind of satellite would move at that speed?

[fmeschia]

Could it be a satellite at one of the Lagrange points?

I'm not skilled enough do do the analysis, but maybe someone else on here might have a feel for it.

This is an interesting idea. The imaged field is quite close to where the Lagrange point L2 would have been, although not quite on it. But satellites orbit L2 rather than sit at it, so I guess it’s possible.

[dcbrown73]

The closet Lagrange point is almost a million miles away.   If it were something there, It would have to be gigantic to be able to see it.   The largest satellite is the ISS and it's 254 miles away and it's quite small at that distance.  The Lagrange point is 3,669 times further out than the ISS.

 

Maybe a drone?   Just throwing out ideas.

[fmeschia]

The closet Lagrange point is almost a million miles away.   If it were something there, It would have to be gigantic to be able to see it.   The largest satellite is the ISS and it's 254 miles away and it's quite small at that distance.  The Lagrange point is 3,669 times further out than the ISS.

 

Maybe a drone?   Just throwing out ideas.

People have imaged the JWST which is at L2. Of course it’s just a dot, but it’s what we have here: we’re not seeing the shape or size of an object, but its trajectory across the sky. In any case I don’t think this is the JWST, it’s too bright.

Unlikely to be a drone as well... it moved in a curved but apparently smooth trajectory for almost two hours, at an average angular speed of 10 arcmin/hr.

Edited by fmeschia, 21 April 2025 - 11:20 AM.

[JWolf_21]

People have imaged the JWST which is at L2. Of course it’s just a dot, but it’s what we have here: we’re not seeing the shape or size of an object, but its trajectory across the sky. In any case I don’t think this is the JWST, it’s too bright.

Unlikely to be a drone as well... it moved in a curved but apparently smooth trajectory for almost two hours, at an average angular speed of 10 arcmin/hr.

The thing is that we can know exactly where the L2 point is in the sky, right? and with the trayectory you have there, you can calculate the center of the circunference. 

 

https://www.cuemath....try/arc-length/

 

You can even get a screenshot of Sky Charts or any star chart software that you use, and overlap with transparency on your picture, and directly draw the lines between the L2 point and your trajectory, and check if they make sense.

 

If L2 and the center of that circle are close to each other it would be time to check the list and magnitude of satellites in L2

[dcbrown73]

People have imaged the JWST which is at L2. Of course it’s just a dot, but it’s what we have here: we’re not seeing the shape or size of an object, but its trajectory across the sky. In any case I don’t think this is the JWST, it’s too bright.

Unlikely to be a drone as well... it moved in a curved but apparently smooth trajectory for almost two hours, at an average angular speed of 10 arcmin/hr.

Well, even so the Lagrange point's halo orbit is hundreds of thousands of miles around.   You wouldn't see that type of curvature from the image above in it's orbital path as I believe it takes six months to make a full orbit.  Though I have seen an image that an APer took over 45 minutes that shows movement.

[fmeschia]

The thing is that we can know exactly where the L2 point is in the sky, right? and with the trayectory you have there, you can calculate the center of the circunference. 

 

https://www.cuemath....try/arc-length/

 

You can even get a screenshot of Sky Charts or any star chart software that you use, and overlap with transparency on your picture, and directly draw the lines between the L2 point and your trajectory, and check if they make sense.

 

If L2 and the center of that circle are close to each other it would be time to check the list and magnitude of satellites in L2

 

 

Well, even so the Lagrange point's halo orbit is hundreds of thousands of miles around.   You wouldn't see that type of curvature from the image above in it's orbital path as I believe it takes six months to make a full orbit.  Though I have seen an image that an APer took over 45 minutes that shows movement.

Both good points and suggestions. I just checked the precise position of L2 at that moment, it was off to the right and below the FOV, so the path would be in the wrong direction for a halo orbit. Then it wasn't something at L2...

Edited by fmeschia, 21 April 2025 - 11:49 AM.

[JWolf_21]

Both good points and suggestions. I just checked the precise position of L2 at that moment, it was off to the right and below the FOV, so the path would be in the wrong direction for a halo orbit. Then it wasn't something at L2...

I like to test easiest things first, so done, L2 discarded... Now let's talk about UFOs....  

[WadeH237]

What is the orientation of your frame?

 

I once watched what I believe was a tumbling satellite in a polar orbit in the eyepiece.  It was interesting due to the constantly changing brightness.  It was slowly drifting northward in the eyepiece.  By periodically moving the scope north, I and a few other people were able to follow it for about 45 minutes before we moved on to something else.

 

I've not thought through the geometry, but Earth would have rotated a bit over 10 degrees during the time that we observed it.  In a deep sky imaging session, I suspect that it would have a curved path.

 

If your frame is oriented with N/S up and down in the  field, is it possible that you caught something similar?

[fmeschia]

The orientation is North-up and East-left. The sides of the frame are parallel to the celestial grid lines.

I think it would be possible, but the velocity seems too slow for a satellite orbiting the Earth.

I've seen a weather balloon doing what you described, and tracked it visually with a Dob. But a balloon drifts with the airmass, whereas the telescope here was tracking the stars: in almost two hours I would expect a very different drift.

Edited by fmeschia, 21 April 2025 - 12:14 PM.

[Zambiadarkskies]

Chinese spy balloon?

[fmeschia]

Somehow I managed to forget to even indicate the position where this happened. The galaxy visible in the animation is M96; the coordinates of the approximate midpoint of the track are RA 10h46m24.5s Dec +12°05’13.3”. 

[vtaDan]

The IM-2 vehicle is a possibility. It launched directly into lunar transfer so its apparent motion could be roughly 15 degrees per hour. You should send them the pic and video you included above. Their orbital analysts could figure it out.

[WadeH237]

The orientation is North-up and East-left. The sides of the frame are parallel to the celestial grid lines.

I think it would be possible, but the velocity seems too slow for a satellite orbiting the Earth.

I've seen a weather balloon doing what you described, and tracked it visually with a Dob. But a balloon drifts with the airmass, whereas the telescope here was tracking the stars: in almost two hours I would expect a very different drift.

The object that I described was not a weather balloon.  It was near midnight, and the object was rapidly and irregularly fluctuating in brightness, and was far too faint to be seen naked eye.

 

Regarding the velocity, it was moving from south to north slowly enough that we followed it for 45 minutes with a 31 Nagler in my C14.  It took nearly a minute to drift the entire diameter of the field, and we just used occasional bumps on the move buttons to stay with it.

 

My conclusion is that it was a tumbling object on a highly elliptical polar orbit.  If it was near apogee, the apparent movement could be very small.

 

If someone has a better explanation for what I saw, I would be interested.  But whatever it was, the path it took was similar to what you captured.

[Dan Crowson]

Just from the look of it, this looks like space junk to me. It looks similar to launched things I've purposely imaged in the past. I suspect you could plug the time and coordinates into Heavens Above or one of the interfaces to findorb and it would spit out something.

Dan

[WildMarker]

To my eye, I see multiple separate objects each going in a straight line.  They just happen to resemble a curved path when shown together.

What are your sub lengths, and what is your sequence like?  Sub length can help calculate the object(s) speed. 
What is happening during the large gaps, and how much time is passing during those gaps, between the dashed groups?  Autofocus?  Other filters? 

[fmeschia]

The sub length was 180 seconds. This is the rejection map for L, and the gaps you see are because my sequence was running like LLLLLRGBLLLLLRGB etc. I'm fairly certain it's the same object, I can actually see it in the "gaps" when I look at the RGB frames.