Bright Objects in the Morning Sky—December 2018

The other morning promised an interesting alignment of the planets Venus and Mercury, the waning crescent Moon (3.4% illuminated), and the bright star Spica (Alpha Vir, the brightest star in the constellation Virgo) in the morning sky. All that was required was clear skies.

Morning twilight with Mercury, Venus, Spica, and the Moon (0629 MST 05 December 2018).
Morning twilight with Mercury, Venus, Spica, and the Moon (0629 MST 05 December 2018).

Various weather models showed essentially the same forecast. There would be a band of high clouds to our northwest and another band to our southeast. Overhead it would be clear.

And the forecasts turned out correct. Below is a satellite image taken at ~1330 UTC (0630 MST) showing a nice clear gap in the clouds.

IR satellite image at 1332 UTC (0632 MST) showing the gap in the clouds across northern Arizona.
IR satellite image at 1332 UTC (0632 MST) showing the gap in the clouds across northern Arizona.
Model forecast for cloud cover. White/gray is cloud; black is clear.
Model forecast for cloud cover. White/gray is cloud; black is clear.

I drove to the overlook on Mars Hill, home of Lowell Observatory, in Flagstaff. It has very good views towards the east and is a location I have used many times over the years for astrophotography.

Comet 46P/Wirtanen Approaches

The much-anticipated Comet 46P/Wirtanen is nearing its closest approach (approximately 30 lunar distances) to Earth. From the SpaceWeather.com site (cited 11/28/2018):

Small but hyperactive Comet 46P/Wirtanen is approaching Earth and could soon become visible to the naked eye. On Dec. 16th, the kilometer-wide ball of dirty ice will be less than 11.5 million km away–making it one of the 10 closest-approaching comets of the Space Age.

Earlier this week I made my first attempt at photographing the comet. I had patiently waited until the Moon was several days past full so that I could capture images of the comet without the interference of moonlight. I wasn’t successful because the moon was already rising by the time I was completely set up. Even with the bright sky in the presence of an 85% illuminated moon, I was able to get acceptable images.

Not only was this my first effort to photograph the comet, it was my first effort to even find it in the sky. Having a pair of binoculars helps.

I used a Nikon 85mm f/1.8 lens because it has a moderate field of view (24°x16°) and is a “bright” lens. It can [usually] successfully autofocus at night using bright stars, planets, or best, the moon. And, as I mentioned above, the moon was already above the horizon.

Comet 46P/Wirtanen (85mm, f/2.8, ISO 400, 15x60s)
Comet 46P/Wirtanen (85mm, f/2.8, ISO 400, 15x60s)

Later, I switched the lens and used my ancient manual focus Nikon 80–200mm zoom lens. This lens is almost 40 years old—and from the images it appears that it needs some servicing. Many of the stars have a “bulge” in the upper left. Maybe I’ll send it to Nikon servicing—if they still work on this old lens.

Comet 46P/Wirtanen (200mm, f/4.0, ISO 800, 6x60s)
Comet 46P/Wirtanen (200mm, f/4.0, ISO 800, 6x60s)

We are now entering an extended period of unsettled weather across the southwest U.S. and there may not be another chance to capture images of the comet for some time. I hope the weather is clear on the night of December 15 when the comet passes very close to the constellation Pleiades. That should make for an interesting sight!

Comet C/2018 V1 (Machholz-Fujikawa-Iwamoto) in the Morning Sky

Venus and Spica in the morning twilight.
Venus and Spica in the morning twilight.

There’s a new comet in the morning sky. The comet was discovered in early November by three amateur astronomers—one in Arizona and two in Japan. Nowadays, most comets and asteroids are discovered by robotic Near-Earth-Object (NEO) search programs. The discovery of a comet by amateur astronomers is becoming a rare event.

So, with that bit of information, I set out to capture some images of the comet. As an 8th magnitude object it would not be easy using a short telephoto (i.e., 85mm focal length). My first attempt was marred by clouds but after viewing the images later I was finally able to find the small and not very bright comet.

A few days later I tried again. And, once again, high clouds moved across the sky. Finally, just before twilight, the clouds moved out of the way and I was able to get about 25 minutes of images.

 

Because the comet is so dim, individual images are not very revealing. In this case, better results are obtained by creating a short animation over the 25 minutes showing the motion of the comet relative to the stars.

As the eastern sky brightened the planet Venus and nearby star Spica stood out (image at top of post). A very nice end to a morning of shooting photographs in the cold.

Autumn Colors in Northern Arizona—2018

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.

Aspen leaves on Weatherford Trail.
Aspen leaves on Weatherford Trail.
Waterline Road.
Waterline Road.
Inner Basin Trail after an early-season snowfall.
Inner Basin Trail after an early-season snowfall.
This is the classic shot along Waterline Road.
This is the classic shot along Waterline Road.
Waterline Road.
Waterline Road.
Near Arizona Snowbowl.
Near Arizona Snowbowl.
Snowbowl Road after an early-season snowfall.
Snowbowl Road after an early-season snowfall.
Weatherford Trail.
Weatherford Trail.
Frozen water droplets on a leaf.
Frozen water droplets on a leaf.
Colorful hillside along the Elden Springs Trail.
Colorful hillside along the Elden Springs Trail.
Reflection in Frances Short Pond.
Reflection in Frances Short Pond.
Inner Basin and the Kachina Peaks Wilderness.
Inner Basin and the Kachina Peaks Wilderness.

 

Fog and Atmospheric Optics

Fog with a Glory, Brocken spectre, and two segments of a fogbow.

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!

GOES-16 IR satellite image from ~5 a.m. showing large areas of fog across northern Arizona.
GOES-16 IR satellite image from ~5 a.m. showing large areas of fog across northern Arizona.

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.

Sunrise through the fog.
Sunrise through the fog.
Layers of fog at sunrise.
Layers of fog at sunrise.

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.

Fog with a Glory, Brocken spectre, and two segments of a fogbow.
Fog with a Glory, Brocken spectre, and two segments of a fogbow.
Fog begins to dissipate across the Mormon Lake basin.
Fog begins to dissipate across the Mormon Lake basin.

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.

Fogbow near Lake Mary.
Fogbow near Lake Mary.

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.

Another glory and Brocken spectre projected onto fall foliage.
Another glory and Brocken spectre projected onto fall foliage.

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.