Some of our best natural experiences occur close to home.  On December 7th, just after dark, Andrea was driving up to where we park our cars at the farm.  As she pulled in, she saw a Barred Owl perched about 15 feet off the ground in a small White Ash.  Knowing that I was inside and not wanting to disturb the owl, she telephoned me before cutting off the engine or dimming the headlights.  We worked out a plan to try to get an image, knowing that to approach an owl at night without making it fly is not easy. 

We decided she would back up about 10 feet so that the owl was not directly in the headlight beams.  She left the headlights and engine on, then crept up to the house while I hurriedly put together an arrangement to photograph the owl.  I then walked slowly down to the car, not knowing if the owl would still be there.  Amazingly, it was still there, and I eventually got to within about thirty feet of it before it flew.  Manual focusing was very tough, because the owl was only indirectly illuminated, and very faint in the viewfinder.  The light was much too faint for autofocusing.  Out of all of the images, only one image was in crisp focus, and luckily it was one of the close shots.  The owl flew after a couple more images, but only to another tree about 100 feet away.  I left it to resume its hunt.

On December 12th we drove down to Chattanooga, Tennessee to do a Tennessee Naturalist Program.  The program was at Audubon Acres, a beautiful 130 acre sanctuary that serves as the headquarters for the Chattanooga Audubon Society.

Our program was scheduled to begin at 4:00pm, and we arrived early to scout the trail for a night hike we would be doing later that evening.  A warm front was making its way into the area and the sky was laced with high cirrus clouds.  About 3:30pm we looked up to see a beautiful circumzenithal arc directly overhead. 

I didn't have a camera with me other than my iphone, but no image can truly capture the beauty of these arcs.  When viewed with the naked eye, they have an ethereal quality to them.  The colors appear to wax and wain as the ice crystals that form them drift with the high altitude winds.  As the name implies, circumzenithal arcs are arcs around the zenith, the point directly overhead. 

Also faintly visible were parts of the 46 degree tangential arc.  This is an arc around the Sun that just touches the lower portion of the circumzenithal arc and can be faintly seen in the image extending to the right of the brighter circumzenithal arc.  A part of the 22 degree halo can be seen through the branches near top of the tree in the center of the image.  The Sun is mostly hidden behind the trunk of this tree.  The arcs were actually more visible to the eye than the camera.

If you want to see these arcs, always, always check the sky overhead if you see faint wispy cirrus clouds in the sky.  Often these cirrus clouds precede a warm front during the winter months.  An hour or two before sunset seems like a good time to see the arcs.  Conditions for arcs may be particularly favorable if you see "sun dogs," bright colored patches of sky 22 degrees on each side of the Sun.  The most common arc around the Sun (or Moon) is the 22 degree halo.  But don't forget to look overhead.

There is some rather nifty free software out there if you want to simulate arc phenomena.  One of these is HaloSim3, which can be downloaded from the Atmospheric Optics site.  We have not yet tried out this software, but we plan on trying it out soon and we'll let you know how it works for us.

We later had a wonderful night hike at Audubon Acres and had a great look at a Barred Owl.  The sky show continued as well, with a bright corona around the full Moon.  Many thanks to the Audubon Acre staff for all of their hospitality and a very memorable evening.

Evening Sky:  

Bright Venus sets in the southwest around 8:30pm at the beginning of the month.  It will reach greatest elongation from the Sun on January 12th.  Look for pretty pairings of Venus and the crescent Moon early in the month.