What is it?
Brocken Spectre happens when the sun is at the antisolar point and creates a shadow. Not only just a regular shadow on a wall but a shadow up above the clouds or mist. Whether it is on a mountain ridge or up in a plane, the shadow will have a bow or halo. The shadow will be bigger than usual because the shadow doesn’t have something solid to project on in the mist or cloud. The moisture in the cloud, mist or fog will create a bow. Will it always be a rainbow? It might not be. It will depend on the kind of moisture in the cloud, mist or fog.
What is the difference between an antisolar point and just seeing the sun through the clouds? The antisolar point is when the head of your shadow is in line with the sun behind the object or person.
Where did it get its name?
Well, the reason it was named Brocken Spectre came from the Brocken which is a peak in the Harz Mountains, in Germany. Spectre refers to a ghost or an apparition. It was first observed by Johann Silberschlag in 1780. In this area, there are a lot of low lying fogs. The opportunity to see one is higher.
Johann was a German Lutheran Pastor and a natural scientist. He tried to reconcile theology and science. Did you know that there is a lunar crater named after him? It is a perfect round crater.
Whenever you get the chance to be high on a peak, ridge or just in an airplane, watch for this phenomenon. Look down on the clouds as you fly over in an airplane. Maybe by chance, you will get to see a Brocken Spectre. It would be amazing, to say the least.