Late summer rain showers and rainbow

The past few weeks have produced some very fine late summer weather across northern Arizona. Warm days…cool nights…light winds…and clear blue skies day after day.

But that gets boring after awhile so I was happy that we had a change of weather this week. Copious amounts of tropical moisture have surged northward across Arizona just as a weak Pacific weather system and cool front swept eastward across the state. The result was a night and day with on-again, off-again rain showers and a few thunderstorms.

Rainbow and anti-crepuscalar rays over northern Arizona.
Rainbow and anti-crepuscalar rays over northern Arizona.

Late in the day the clouds were pushing to the east and the sun was beginning to shine in the west producing the right conditions for a rainbow and for anti-crepuscular rays. AC rays are those alternating bands of light and dark seen in the opposite direction of the sun. The Atmospheric Optics web pages describe these and many more optical phenomena.

Rainbow over the San Francisco Peaks.
Rainbow over the San Francisco Peaks.

This was only a partial rainbow and the other end was located in the midst of the San Francisco Peaks north of Flagstaff.

A very nice end to an interesting weather day.

International Space Station transit at twilight

The other day the International Space Station (ISS) made a transit of the western sky during twilight. Low on the horizon was the planet Venus with the ISS streaking across the sky above. I’ve been shooting images of the ISS for a year or two but think this is one of the best. It works for a number of reasons. One is the bright twilight on the horizon deepening into dark night sky above. The planet Venus — and its reflection in the water — add a counterpoint.

To create this image I set the camera on continuous shoot and then used the remote release to start. The images are ISO 200, f/4.0, 28mm wide angle lens, and 10s exposures. Five images were taken so this is 50 seconds of transit.

I opened all five images in Photoshop with each image a layer. Because 50 seconds is long enough for stars to leave trails across the sky — even with a wide angle — I wanted to only use one sky layer. In the other four layers I masked the stars and sky and left only the track of the ISS. The result is sharp points for the stars and Venus and a smooth track for the ISS.

Twilight transit of the International Space Station (ISS).
Twilight transit of the International Space Station (ISS).

To get daily updates on transit times of the ISS — and other space satellites — I use the following two web sites:

Spaceweather.com (http://www.spaceweather.com)

Heavens-Above.com (http://www.heavens-above.com)

Perseid meteor shower

Did you get a chance to view the Perseid meteor shower this year? It peaked on the evening of August 12-13 but meteors were visible for many days preceding the peak. With the moon just a few days past new and setting early the skies were very dark for optimal viewing. A maximum rate of more than 100 meteors per hour has been reported with this years event. This compares with a more typical maximum rate of about 50-80 per hour. So this was a better than average event with higher numbers as well as very dark skies.

Triple planetary conjunction of Venus, Mars, and Saturn along with the crescent moon.
Triple planetary conjunction of Venus, Mars, and Saturn along with the crescent moon.

But to make things even better there was a three-way planetary conjunction taking place at the same time. In the western sky after sunset an observer could see the planets Venus, Mars, and Saturn close together along with the crescent moon.

For the meteors, I used a 28mm wide angle lens, ISO 3200, f/4.0, and 30s exposures. I set the camera to continuous shooting mode and let it run until the card filled a few hours later. I then reclined on a lounge chair with a sleeping bag draped over me.

Two Perseid meteors streak across the early morning sky a few days before the peak.
Two Perseid meteors streak across the early morning sky a few days before the peak.
Perseid meteor passes by the constellation Pleiades.
Perseid meteor passes by the constellation Pleiades.
Perseid meteor streaks across the Milky Way with the San Francisco Peaks on the horizon.
Perseid meteor streaks across the Milky Way with the San Francisco Peaks on the horizon.

Even though I saw a large number of meteors with my eyes — and some of them were spectacular long-path events with residual debris trails — the camera captured far fewer because the field of view of even a wide angle is not wide enough to view the entire sky

Mountain biking in Flagstaff. Part 2: 6500 feet

A previous post talked about mountain biking in Flagstaff along the high elevation sections of the Arizona Trail. Not too far away is another section of the Arizona Trail — this time at an elevation of about 6500 feet. The vegetation is different — and quite green because of all the rain lately — and the trail is more open.

This particular section of the Arizona Trail starts along Old Walnut Canyon Road on the north boundary of Walnut Canyon National Monument. It travels through Ponderosa Pine then moves into Pinyon-Juniper with wide open vistas. There are old homesteads along the trail with collapsed buildings and old toys in what was once someones yard.

View of the San Francisco peaks near Flagstaff from the Arizona Trail.
View of the San Francisco peaks near Flagstaff from the Arizona Trail.
Riding singletrack near Flagstaff on the Arizona Trail.
Riding singletrack near Flagstaff on the Arizona Trail.
The front wheel is all that remains from a young child's tricycle.
The front wheel is all that remains from a young child's tricycle.

Mountain biking in Flagstaff. Part 1: 9000 feet

Flagstaff has a variety of great mountain biking trails. Some of these trails start right in the city or at the city edge; others require only a short trip out of town to the trail head.

In addition to local trails, sections of the Arizona Trail pass through Flagstaff and the nearby mountains. One of the newer sections north of town has some excellent riding through groves of aspen trees.

Riding amongst the ferns and aspens -- and the occasional elk -- on the Arizona Trail.
Riding amongst the ferns and aspens -- and the occasional elk -- on the Arizona Trail.
Aspen trees in full autumn color along a section of The Arizona Trail.
Aspen trees in full autumn color along a section of The Arizona Trail.

This is an amazing ride when the leaves begin to change color in the autumn and the shadows start to get long.

It’s also a good idea to keep a sharp eye for elk wandering through the woods and along the trail. After all, it’s important to share the trail with ALL users!