Although people have observed clouds for tens of thousands of years, one group of clouds long escaped human detection. Not because those clouds were too small to see, but because they were too big. The dawn of the satellite era changed that, revealing a type of cloud that scientists named “actinoform.” The name of these radial, or leaf-shaped, clouds is based on the Greek term for “ray.”

The first recorded detection of an actinoform cloud occurred on August 16, 1962, southwest of Hawaii. NASA’s Television Infrared Observation Satellite V (TIROS V) observed a chain of the clouds west of Peru on October 7, 1962.
Rest of the story & links & pictures here. http://earthobservatory.nasa.gov/IOTD/view.php?id=78562&src=eoa-iotd

Deano those two photos safe amazing - prefer the top one though as looks like a hoar frost has got to the clouds.
Thanks for the article very informative.