What did I capture here? Meteor or space junk breaking up?

[Peter Prendergast]

Took this last night and found it in the stack this morning. Looks like either a piece of space junk or small meteor broke up. What do you think?
Peter
PS, FITS header included.

https://www.dropbox.com/s/fu7y2wp2zr...21-Blue-B2.fts

[Bob Denny]

All of the trails are exactly the same shape and speed. That makes this look fishy. But the "objects" are quite faint compared to others so it can't be mount movement. If the objects are real they are in air (friction) and gravitational field. If real I'll guess meteor breakup.

[Dick Berg]

Hi Peter, Was the image immediately before (or maybe immediately) after this one of the same star field? I would agree with Bob's assessment, except that the trails are absolutely identical in shape, which suggests to me an image taken while slewing. NONE of those trailed "stars" in your image are stars found in the field of the Cocoon Nebula (at that brightness). A simple comparison with a planetarium program will show that (two positive images attached).

SECOND THOUGHTS:
I thought I would be smart and mark the heads of these streaks on a clean piece of paper and then send the image to Astrometry.net to see where in the sky it was. But as soon as I marked the heads, I recognized right away that it was indeed the same FOV but shifted diagonally NW<>SE about (very about) 200 pixels, or 200 arcsec. You'll see this in the negative image, where I've marked almost all the stars with tails to their corresponding round star image. (The faint rectangle in the middle is an artifact of my scanner.)

So the question you need to answer then is why was there a double exposure, and what caused the streaking. I think that the streaks are caused by the telescope slewing away from (or maybe to) its tracking position. (Slew starts south (moving streak up; north is at the top) first, then slew east starts, and as the slewing gets up to speed the trails fade.) But I don't know why there's a double exposure. This is probably a one in a thousand event that will remain a mystery.

[Bob Denny]

I think Berg is on to something, which is why I said the trails being the same shape is fishy.

[Peter Prendergast]

I agree, this is a weird situation. No, this was the last in a set of three pictures. Someone suggested that the camera may not have flushed properly. Well, what ever it was it was interesting to research.
Thanks for taking the time to analyze this photo. I too was suspicous the stars were not in the cacoon nebula, but as you noted, they were indeed, just shifted.
Peter

[Peter Prendergast]

OK, while getting ready tonight, here was a pointing exposure and it exhibits similar artifact. Note the streaks yet the overwhelming body of stars is just fine.
https://www.dropbox.com/s/rskzc25mn5...%2072.fts?dl=0

[Dick Berg]

Peter, I haven't had a chance to look at this new image, but I just wanted to mention that there's at least one other forum posting in the last year or so with a similar problem. I'll look for it, and I'll look at your image, when I get home from work this evening. Is the pointing image from the same camera?

[Peter Prendergast]

Right same camera. I wonder if its a shutter problem??? Only happens occasionally and randomly.

[Peter Prendergast]

OK I just spoke to Tim Puckett at Apogee, and he feels this is indeed shutter failure. He's seen this before. I use this equipment a LOT. So, I'll put in a new shutter when this fails a bit more. Right now its to random, but, I'm going to buy the shutter in the meantime.
HTH the next guy!
Pete