Purple Puzzler

Photo date: May 30, 2015. Photographer: Mark Mahin.

The photo below shows a rare purple orb in Grand Central Station in New York (where I mainly get blue and white orbs).

 Below is a closeup (I used the IrfanView "Auto-adjust colors" menu option on this closeup). This type of color helps to exclude possibilities such as dust (even if you deliberately raise a cloud of dust and photograph it, you won't see a purple orb).