Shortly after the miracle, the Catholic lawyer named Coelho said in his article that a few days later, he saw the exact same motions and colour changes in the Sun as he did on October 13th. He says, "One doubt remained with us however. Was what we saw in the Sun an exceptional thing? Or could it be reproduced in analogous circumstances? Now it was precisely this analogy of circumstances that presented itself to us yesterday. We could see the Sun half overcast as on Saturday. And sincerely, we saw on that day the same succession of colors, the same rotary movement, etc." Meessen observes that Sun Miracles have been witnessed in many places where religiously charged pilgrims have been encouraged to stare at the Sun. He cites the apparitions at Heroldsbach, Germany (1949) as an example, where many people within a crowd of over 10,000 testified to witnessing similar observations as at Fátima. Meessen also cites a British Journal of Ophthalmology article that discusses some modern examples of Sun Miracles. Prof. Stöckl, a meteorologist from Regensburg, also proposed a similar theory and made similar observations. Critics also suggest that a combination of clouds, atmospheric effects and natural sunlight could have created the reported visual phenomena. Steuart Campbell, writing for the edition of Journal of Meteorology in 1989, postulated that a cloud of stratospheric dust changed the appearance of the Sun on 13 October, making it easy to look at, and causing it to to be yellow, blue, and violet, and to spin. In support of his hypothesis, Campbell reported that a blue and reddened Sun was reported in China as documented in 1983. Paul Simons, in an article entitled "Weather Secrets of Miracle at Fátima", stated that it is possible that some of the optical effects at Fátima may have been caused by a cloud of dust from the Sahara. Skeptical investigator Joe Nickell wrote that the "dancing sun" effects reported at Fátima were "a combination of factors, including optical effects and meteorological phenomena, such as the sun being seen through thin clouds, causing it to appear as a silver disc. Other possibilities include an alteration in the density of the passing clouds, causing the sun’s image to alternately brighten and dim and so seem to advance and recede, and dust or moisture droplets in the atmosphere refracting the sunlight and thus imparting a variety of colors". Nickell also