Weird tandem Satellite?

Comet NEOWISE below the Big Dipper. The bright streak in the lower right is the International Space Station passing through the shot.

I shot some photos of Comet NEOWISE around 11:00 PM Eastern Daylight Time on 7/23/2020. The comet is past its peak, and relatively low in the sky, so with even rural Michigan light pollution it was not especially photogenic. I then turned my camera toward Cassiopeia, in the hopes of capturing the Andromeda Galaxy (M31) for the first time. I got some pictures, but with my wide angle lens, and with M31 being fairly low in the sky at that time, the photos were not impressive.

Faint tandem objects and brighter Starlink 1098 about to “enter” Cassiopeia.

In viewing the photos, though, I notice something odd. There are very many satellites orbiting Earth, and they often photobomb star images (this is not odd, just annoying). In several shots of Cassiopeia, though, I noticed a pair of very faint objects, moving in tandem from southwest to northeast (from the top of the image toward the bottom; [EDIT: I had originally stated that the movement was from south to north, but upon reflecting on the camera orientation I have corrected that]). They had no flashing lights (satellites typically do not) and they moved at a constant speed over the course of 8 10-sec photographs taken sequentially (with 10-sec dark frames interspersed, and a 0.5 sec delay between each dark frame and the next image); the objects were thus photographed over the course of 164 sec.

Detail from other image – tandem objects are a bit easier to see.

I found them only after examining the photos an hour or so after taking the photos. Stellarium-Web is a great program for identifying objects in the sky, including an extensive database of satellites. However, these tandem objects do not appear. However, the time of my observation can be pretty accurately determined, as Starlink 1098 (one of Tesla’s many, many internet satellites) passed into Cassiopeia from southwest to northeast at essentially the same time as the two objects from my vantage point (42.261578, -84.862236). Both Starlink 1098 and the objects were in multiple photos, so it’s possible to determine the the tandem objects were moving at approximately the same angular speed as Starlink. See an annotated image here.

All of my photos that include the objects are here in somewhat reduced resolution, and here in the highest resolution that I have. Astrophotography is not my forte; a better photographer might produce better images from what the camera gave me.

The  animation  below  might  make  the  objects  easier  to  see,  as  our  eyes  are  very  good  at  detecting  motion.  They enter at the top of the image, about 1/4 of the way across from the left, and proceed straight down. Starlink 1098 enters from the left side, near the top, and crosses diagonally down through the image.  An aircraft appears in the top center and proceeds diagonally down to the right. Starlink and the faint tandem objects pass through Cassiopeia (near the center of the image) at about the same time, with Starlink entering just before the objects.

This screenshot from Stellarium-web shows that Starlink was at this position at about 23:07:30 on this date. 

I am really curious now. I’ll keep trying to determine what I saw, but if anyone has an idea please email me at wjwilson@albion.edu to share your thoughts.

 

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