Star trails from a long exposure astro photography. One additional light source is also present in the picture which someone interprets as TB2 but it could be anything really. We could calculate the exposure time and radius from the star trails to see if it could be TB2 or just a small quad-copter.
Edit: it looks like 120s exposure so the air-craft needs to make a full circle in that time. I would assume that it is a small quad-copter at short distance but it could be TB2 if it makes a very tight curve with 1.0-1.5km radius.
This calculator goes beyond the basic “500 rule” to determine the best shutter time for non-tracked astrophotography on a fixed tripod. Rather than just focal length, this calculator al…
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