The colors have peaked and the leaves have fallen across the higher elevations of northern Arizona. Here are some of my favorites from this season.
Autumn Colors in Northern Arizona—2018
Fog and Atmospheric Optics
In the wake of a departing low pressure system I expected that there might be areas of dense fog in the morning. I awoke well before sunrise to look at satellite images to see if fog was developing. And, yes, there were some hints that fog was present. Good!
I left the house around 6 a.m. and headed east on Lake Mary Road. A few miles outside of town I ran into fog. Visibility dropped quickly to around 1/4 mile. Drive carefully!
My destination was the Mormon Lake Overlook. I had some success last winter at this site with a similar fog situation. As I approached the overlook the fog lifted becoming a low cloud deck above me. Hmmmm….not quite what I wanted. Ahead, I could see the edge of the cloud/fog. As I made the final approach to the overlook the road gained a bit of elevation and, suddenly, I was above the cloud/fog deck. Wonderful.
The sun had not yet risen but it was light enough to see that there was a shallow layer of fog covering the Mormon Lake basin. Moments later the sun began to rise through the dense fog.
With the sunrise a Glory and Brocken spectre became visible. Moments later, two short segments of a fog bow appeared. Also visible is a shadow of the overlook.
As the fog began to dissipate over Mormon Lake, I headed towards Anderson Mesa Station (home to several telescopes) because it is high enough to be above the fog. But first, along the way, the road dropped down into the fog and I saw this fog bow.
Finally, atop Anderson Mesa I once again was above the fog and able to photograph a Glory—this time projected onto trees with autumn colors.
Finally, here is a time-lapse of the fog over Mormon Lake that includes the Glory and the right-hand side of the fog bow.
Edit: Replaced GOES-16 visibile image with IR image.
Severe Thunderstorms Near Two Guns
By late morning it was evident that convection was going to be interesting. Updrafts were quite vigorous and there was pileus atop many updrafts.
I thought about photographing storms but got sidetracked. Then I heard the first Severe Thunderstorm Warning on NOAA Weather Radio. Less than an hour later a Tornado Warning was issued.
I looked at the radar data for the warned storm but was unable to see a clearly defined mesocyclone or tornado vortex signature (TVS). As it turns out, this was a non-supercell tornado (NST), sometimes called a landspout—and landspouts are often difficult to detect by radar.
This warning finally got my attention. A short while later, I headed out the door to see if any other storms would be as interesting as this one. I drove east towards some existing convection near and north of Winslow—stopping frequently to take photographs.
New storms then began to form back to the west and I set my sights on these. By this time, I had moved back west to the Two Guns exit on Interstate 40. Two Guns is now a ghost town and there are several old and interesting buildings in the area. I set up so that I could photograph both the old buildings and the storm. That worked out well.
Then it was time to move to the north side of I-40 so I could get some photos without any buildings in the way. You know—just in case a tornado formed.
No tornadoes were observed although for a brief period the visual appearance and radar depiction suggested that the storm was developing supercell characteristics and had some rotation.
I shot both still images and video. Unfortunately, the dynamic range from the brilliantly lit updraft to the dark shadowy areas elsewhere was too much for the video and portions of the updraft were overexposed.
Still, the video shows some interesting evolution. Thirty minutes (1711–1741 MST) of raw video was compressed into ~18 seconds.
First Snow—Last Flower
The first snowfall and probably the last wildflowers of the season.
A look at Comet 21P/Giacobini-Zinner
Comet 21P/Giacobini-Zinner is a periodic comet with an orbital period of 6.6 years. It made its closest approach to Earth on September 10–11 when it was ~58 million kilometers distant. At that time it brightened to around magnitude 7—which is still too dim to be an unaided eye object. Binoculars, telescopes, or long-exposure photography is still necessary.
My first attempt to capture images was on September 15 when the comet passed in front of M35. Oddly enough, I was unable to clearly see the comet because of the large number of stars in the star cluster.
My second attempt was a few days later (September 18) after it had moved away from M35. This was a better setup. But my imaging wasn’t great. Perhaps the sky wasn’t as clear as I thought it was or my technique isn’t as good as I think it is. Either way, the results aren’t as sharp and clear as I hoped.
Still, it was fun—especially the second attempt. After setting up the tripod, aligning the equatorial mount, and getting [almost] sharp focus I let the camera run for over an hour taking 120 second exposures (followed by 120 seconds of Long Exposure Noise Reduction, LENR).
I was surprised (but should not have been) at how much movement there was in the position of the comet in just a bit over an hour. The video covers the time period from 0320 to 0431 MST.
I also used Deep Sky Stacker (DSS) to stack the individual images in which the software keeps the comet sharp while the stars have trails. Because of the 2-minute gaps between images, there are also gaps in the star trails.
During the 1-hour period in which the camera was on “autopilot” I was able to lie back and stare up at the sky. I saw about two dozen meteors during that period and many of them seemed to have origins near the constellation Orion. The Orionid meteor shower doesn’t peak for another several weeks (active from September 23rd to November 27th with a peak on October 21–22) but it’s possible these were early arrivals of that meteor shower.