When the air quality works as a solar filter...
(Really cool, but on a safety note, you should still use a filter. Visible light is blocked well, but high intensity infrared and sometimes UV could still pass through, damaging your eyes or equippment. Better safe than sorry. It's probably fine for a quick snap, but a video or timelapse definitely needs a filter. Non-visible light can still damage sensors, and with longer exposure, eyes. Great shot though.)