C/2017 K2 (PanSTARR) is a comet discovered around five years ago. It is notable for the amount of activity it exhibited despite being so far from the sun. It is at its brightest from Earth this week at a distance of 'just' 270 million kilometers. When it reaches its closest distance to the sun (perihelion) it will be closer to Mars and less visible. This image shows the superimposed core arcing across the sky for about 30 minutes.