A Hole-Punch Cloud

We were just setting up the telescopes when I looked up and spotted it.

Waikoloa School was hosting a community picnic, a couple bands, food, performances by a karate club and a halau, plus a few telescopes provided by Keck and the West Hawaii Astronomy Club. It promised to be a fun evening.

What I spotted was a hole-punch cloud above the school. OK, that was unexpected. A high thin layer of altocumulus perforated by a neat circular hole.

The hole had a thickened edge as if something had pushed the cloud layer aside. Otherwise it was completely clear in the center and nearly perfectly circular.

Hole punch clouds are often formed when something passes through a cloud layer, such as an aircraft, disturbing and destabilizing it. This does not appear to be the case here, rather I would guess that an updraft from below pushed its way into this particular cloud from below.

The hole was short lived, fading in about 15-20 minutes as the cloud layer reformed.

A Hole-Punch Cloud over Waikoloa
A Hole-Punch Cloud over Waikoloa School

Naked Eye 100 Challenge

Amateur astronomers love lists… The Messier observing list, the Hershel 400, the Hershel II, and on. Some lists can be complete on a night or two, some lists may take years, or even a lifetime to accomplish. Amateur astronomy is not the only avocation to use lists like this. Birders attempt to see all of the birds known to occur in their home country. Aircraft spotters love to see each model of aircraft in the air. Divers keep lists of species seen underwater.

Rainbow Wheel
A rainbow and cloud shadows produce a rainbow wheel
Lists like these are not only fun, but allow the list chaser to sample the wonders our universe has to offer. The challenge of finding and observing each of the items is worthwhile. Each object is a lesson into the science, hunting each object allows skills to be practiced.

Most of the astronomy observing lists require a small telescope to accomplish, or at least a pair of binoculars. One list is a bit different, it does not require any optical aid at all… The Naked Eye 100.

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