Hello
I was going over some of the frames of 2008 BT18 when I noticed that several appeared to suggest some type of gap or discontinuity in the “dashes” recording the passage of 2008 BT during each 60 second exposure.
I selected one frame and ran a contour plot in MIRA AP with an interesting result. On Frame 2008_BT18.00000029, a Contour plot in MIRA AP shows a gap between peaks of around 10 pixels.
At an image scale of 0.81 arcsec/pixel, this would suggest a separation of some 8 arcsecs between two components of 2008 BT18, if this is a real effect and not a system or processing artefact.
On the other hand, maybe this can be attributed to some periodic error in the mount?
SpaceWeather on 13th July 2008 mentions the binary nature of this asteroid.
Cheers
Dennis