William Optics RedCat 51mm Petzval f/4.9 refractor, ZWO ASI 183MC Pro cooled color astronomy camera, SkyWatcher EQ6-R Pro equatorial mount.
Standard-demosaic of a calibrated, single 2-minute exposure, with no other processing performed.
While outside imaging, and using the Pleiades, M45, as a test target for focusing, etc, before moving onto another deep space object, I was watching the ISS pass by.
As it blazed across the sky, I noticed it turning very red, just before it faded into the Earth's shadow.
I have not seen this before. Luckily, the camera caught it.
I assume this is from Rayleigh scattering of the sunlight that was illuminating the ISS.