M15

The globular cluster was shot in the L channel from a balcony in Moscow with an Askar 103apo using the 1x lucky technique (2-sec subs), 2 hours total integration.

Color was added from Uzunovo (south of Moscow Oblast) with a Newton 250 f/3.6, 30 minutes per channel (2-min subs), shot by Dima (smol69).

The green (emerald) star at 11 o'clock from the center turned out to be a tricky puzzle for many. Let me say right away, this is not a processing error, which is confirmed by the color of the other stars — it is quite accurate. I won't write the answer, I'll only give a hint: emerald stars don't exist, everyone knows that, and with a color camera this star would never come out emerald. The whole trick is in shooting color with a monochrome camera through RGB filters.