File:Red rain Kerala optical microscope.jpg

Summary
Red rain in Kerala under an optical microscope at 1000x magnification. Original caption: Photomicrograph of the red rain particles under 1000x magnification. Particles have size variation from 4 to 10 micrometers. Inset shows red rainwater contained in a 5ml sample bottle.

Licensing
The image is non-free fair use in Meteor astronomy.

Fair use for Meteor astronomy
To illustrate the microscopic nature of meteor radiation (specifically the origin of red rain particles), since no picture can be obtained of the meteor radiation itself (the image is of the collected particles from the red rain rather than the red rain itself).

The image linked here is claimed to be used under fair use as:
 * 1) It is a scientifically significant photo of a meteor astronomy phenomenon.
 * 2) It is of much lower resolution than the original (copies made from it will be of very inferior quality).
 * 3) The photo is only being used for informational/educational purposes.
 * 4) Its inclusion in the article adds significantly to the article because it shows the phenomenon depicted in the article and how it has a significant impact on meteor astronomy to the general public.
 * 5) Not replaceable with a free image since this phenomenon is very rare.