Lofted Fog Phenomenon

Photo by Otis: During the early morning May 23, 2022 at 5:23am with an overcast sky, the lofted fog phenomenon was observed and imaged with an iPhone XS Max ISO100 6mm f/2.4 1/122 sec. exposure with a telephoto lens. By 5:43, the patch was gone.

Lofted Fog Phenomenon
The Lofted Fog Phenomenon is frequent, seen over sections of the mountains or the urban city. It can cover the entire city or a mountain range at one time or occur in more readily delineated patches as seen here. The fog is undoubtedly a mix of air pollution smoke particles thus creating smog. When moisture or rain is present, the patch takes on a greater content of mist. These patches move as quickly as fast moving clouds, usually appearing then gone in 20 minutes. In the photo above, the patch appeared and was gone in 20 minutes.

Sucker Holes in Clouds

This sky is completely cloudy and very tricky. It appears to have open spaces in the sky, yet the spaces are all covered with obstructions. There are large amounts of upper atmospheric haze in addition to clouds closer to the ground. At the top, thousands of small clouds have gaps which are changing too fast and are too small for reliable telescope observations. It is possible to observe directly through the haze and apply methods to subtract the haze when the photo is taken or after through software image processing.

Sucker Holes in Clouds
We talked about telescope observing through holes that appear in clouds and then we heard the expression "Sucker Holes" used. Surprisingly the term is real and can apply to both astronomy and aviation.

Sucker hole is a colloquial term referring to a short spate of good weather that "suckers" sailors into leaving port just in time for a storm to resume at full force. It can also refer to breaks in cloud cover, which lead astronomers into trying to make observations, only to have the cloud close in again.

A sucker hole is an unsuccessful observation break in the clouds. Maybe an opening is seen, the telescope is set up, and by the time the telescope is ready, the hole is gone! To deal with the phenomena, the rate of change in position of the cloud is measured per unit time and this can determine how much time might become available for the clearing to remain open before changing. Typically high level atmospheric clouds can move at speeds up to 1,000 mph and bring about changes in only 20 minutes or less. Meandering cumulus clouds can also bring about short term changes just when you least expect it. Upper atmospheric haze is more tricky and can affect celestial objects as if they are being viewed through a thick filter. This may in some instances help when looking at the Sun, Moon or bright planets. On the other hand, contributory dimming of the object, added water vapor, and particles held in suspension may ionize and polarize the region, absorbing, blocking, and scattering light, thus degrading the image.

Astroimaging Through Cloud Cracks & Holes

https://otisastro.blogspot.com/2022/04/astroimaging-through-cloud-cracks-holes.html

Astroimaging Through Cloud Cracks & Holes

Twenty minutes later, compared to the photo below, these additional clouds formed. These clouds are timed to indicate they move at 1,000 mph.

This is an extreme example of clouds with holes and cracks in the early morning - a time when observing the Sun is often ideal. Unfortunately this morning, the clouds remained in front of the Sun and it took another hour for the clouds to move. Taipei 101 at left. Captured through a closed window with iPhone 10. A haze covers everything due to air pollution and smog.

Astroimaging Through Cloud Cracks & Holes
When the weather's so quickly changeable, all efforts must be made to utilize every available opportunity to see the sky and observe the Sun, Moon or planets.

There's a spring season when the overcast and rain break up into clouds with cracks and spaces in between. This is the interim period before the skies briefly clear for a week or two and telescope fever sets in.

These fast changing clouds offer rich observing opportunities for the vigil and patient. Given the speed of cloud movement, there is usually a 20 minute opening. Even so, upper atmospheric haze is nearly always a contention and sky filtration with moisture and haze penetration is highly useful.

Update: Seasonal Variations

By the time Saturday morning, April 9th rolled around, the sky was totally clear and remained until 9:30 am when a few straggler clouds began moving in. It was a period of several hours to observe the planets, Venus, Saturn, Mars and then the Sun was in perfect position.