It was mid-October and that made it a good time to head to southwest Utah for some autumn mountain biking.
We left Flagstaff around 8:30 a.m. and arrived at the Wire Mesa Trailhead on Gooseberry Mesa about 4 hours later. After a quick lunch, we jumped on the Wire Mesa trail. Good news! They are upgrading the parking lot with a fence and possibly other amenities.
This was our first time on Wire Mesa Trail. It’s a nice loop with some great views of Zion National Park and the cliffs of Gooseberry Mesa.
The next day we visited the Gooseberry Mesa trails, starting on Windmill, then North Rim and out to the west end of the mesa. This route wanders between the edge and then through ramps, chutes, small hills, all on a high-traction surface. The geologic name for this rock is Shinarump Conglomerate.
The return to the trail head included a quick jaunt on Yellow Trail. Great fun! We then returned to North Rim and connected with Practice Trail. The photos shown here are very similar to photos taken on earlier trips to this mountain biking area. See, for example, the trip reports for April 2015 and October 2016.
We had planned on a third day of riding but instead opted to do some hiking in Zion National Park.
The weather was perfect with clear skies and light winds in northern Arizona to photograph the transit of Mercury across the face of the Sun.
From Wikipedia: “A transit of Mercury takes place when the planet Mercury passes directly (transits) between the Sun and Earth, becoming visible against the solar disk. During a transit, Mercury appears as a tiny black dot moving across the disk of the Sun.”
Mercury is small so it is difficult to photograph a transit without using a telescope or large telephoto lens. I photographed the transit using a (1) full-frame Nikon DSLR and a 70–300mm telephoto zoom lens, and (2)a Panasonic Lumix FZ150 “bridge camera” with a 600mm [equivalent] zoom. The Nikon takes vastly superior images; the Lumix has more zoom. And the better results came from the Lumix.
The photograph above shows the first image taken as the Sun had partially cleared the cliffs. Subsequent images were stacked and aligned on this image so that it shows a sequence of positions during the transit.
The last transit of Mercury was 09 May 2016; the next will be 13 November 2032. The image above is from the 2016 transit.
Transits of Venus are easier to capture because Venus is much larger than Mercury and also closer to Earth. The last two transits of Venus were 05 June 2012 and 08 June 2004. The next transits of Venus will not occur until 10–11 December 2117 and 8 December 2125. Above is an image of the 2012 transit with a bird also “transiting” the sun.
On Monday and Tuesday (28-29 October 2019) the thin crescent Moon passed near the planets Venus and Mercury in the evening twilight sky. A check of The Photographers Ephemeris indicated that I could set up at Little Horse trailhead near Sedona and capture the thin crescent as it slipped between the spires of Cathedral Rock. Venus and Mercury would also be visible.
Ah, if only is was as easy as that. I never was able to see the crescent Moon.
But, wait! A closer inspection of the images shows that I did capture the crescent Moon. It was only 1% illuminated in a bright twilight sky. If you look carefully at the image and above the two people, you can just barely see a very thin crescent in the gap.
The next evening the Moon was 4% illuminated and higher in the sky making it an easy target. Venus and Mercury were below and the star Antares was to the left. Fitting all four objects in the image was the goal and I was successful. The only issue was the strong winds which resulted in some camera movement during the image capture.
I used Stellarium to determine how the Moon, planets, and stars would look at that time of the evening. I also used the Ocular plugin to show the field of view (FOV) of various lenses and focal lengths so that I could know, in advance, which lens would capture the whole scene. Very helpful!
It has been a dry October and the last measurable precipitation at the Flagstaff airport was September 26 until rain and snow fell on Sunday, October 27.
Forecast models had been showing a slight chance of rain and/or snow with the passage of a cold front but precipitation amounts were light. The GEFS plumes showed generally less than 0.03 inches. The airport actually measured a bit more than that as 0.05″ of rain fell with a trace of snow.
Overall, not a bad forecast. So I was not surprised that rain and some snow arrived with the cold front. I was surprised that it was accompanied by thunder and lightning.
It’s always interesting to observe Thundersnow!
A look at the lightning map shows that the only place where there was cloud-to-ground lightning was in the vicinity of Flagstaff.
It was a dry summer (driest on record in Flagstaff) and autumn hasn’t been too wet, either. And, yet, the autumn colors have been good. Very good, even, with leaves staying on the trees well into mid- and late October.
In early October, the aspen were changing colors on the north side of the San Francisco Peaks.
A week later, the leaves had already peaked along Waterline Road and were falling from the trees and covering the road.