Friday the 13th

Two of my images were unveiled at Perkins Observatory as part of the Ohio Art League Show: The view from Dione. The stormy weather kept the show's opening reception turnout low. It was Friday the 13th, after all. The day produced a couple of nice new images in spite of the weather...

Stellar emission spectra...





The end of Friday the 13th...



Hint:(1 and 3)