Hi guys thanks for all the input. I checked my images and only one image shows the "object" which now seems more and more like a cosmic ray maybe? I thought my stack with Sigma rejection would take care of outliers but it kept it.
Dave that's a beautiful image btw. Gorgeous
Too slow. Would have moved more in that time I think.
Maybe you are only addressing Geosats, but there is danger in dismissing satellites/rocketbodies as not potential candidates based on angular velocity.
Of course, the first assumption might be that because the streak stays within the frame, the object took the 48 minutes (of stack) [not including any delay between images if not calculated] to cross the amount of the streak seen.
However, further investigation you did into the actual subs show it only is seen in one 5 min. sub if I read your post correctly?
So maybe we can assume to narrow its speed into covering that streak in 5 minutes?
But not so fast (pun intended)....
Since only one of the continuous subs (assuming you didn't have a long (multi-minute break) between subs,
then it would not make sense for the subs before the one with the artifact and after to not show a continuation,
IF the streak showed a continuously lit object moving across.
So the speed assumption can only be used if the object is presumed to be continuously lit during its entire travel through the frame.
However, since the before/after frames have no hint of the object,
it would be reasonable to deduct that the one sub captured a flare event of the object into the limiting magnitude(momentary, not integrated LM) of the single 5 min. image,
then the before/after (even maybe during the image with the streak) and the subs before/after would have not captured the continuation because the object had faded/was darker than the limiting magnitude (momentary, not integrated) of the image reach.
With only the shared stack, it is a little pointless to do, but observing an individual sub compared with a starchart one can quickly assess the limiting magnitude of the individual sub. Comparing the brightness of the streak to other stars in the image, finding a star's magnitude that is similar would demonstrate that object would then have to be many times brighter than the comparative star since the star had 5 minutes for its integrated brightness to build in the image while the object moves across pixels and has less time to integrate brighter into its pixels.....Thus one can guess at what the least magnitude the object may be.
Overlaying the image with Equatorial lines, one can estimate the inclination. Note Geosats would trace parallel with the lines from right to left across the image (rotated to EQ configuration)..
Interestingly Ariane 44L Deb, NORAD 23239 (643 minute orbit period) passes near the streak location at ~21:55EST that night. From its radar cross section Calsky estimates its brightness could get to around mag. 10. Its inclined path shows a little different however.
A closer look at the streak shows brightness variations in the pixel brightness,
but that might be attributed to seeing issues (DSO AP'ers forget seeing effects since it is averaged out in a long exposure, but moving objects trace across pixels in short time and can show such artifacts).....Such does lead me to believe it traced across the pixels at a slower pace than a quick streak....
The jaggies betray the object (at least in uploaded image sampling) is only pixel width.
I've captured some cosmic ray streaks (esp. in video) and they often leave a different signature...
Of course the idea of a non-id'd asteroid or satellite could still fit....Considering the flaring effect possibility.
Note people often only think of flares with Iridiums, but a satellite can flare without a slow ramp/up fade/out as Iridiums do.....
Another thing to consider is it could have been a faint telescopic meteor captured at just pixel resolution and attenuated by the h-alpha filter...