Comet C/2023 A3 (Tsuchinshan-ATLAS)–Morning Observations

Comet C/2023 A3 (Tsuchinshan-ATLAS) has been in the headlines and the morning sky for a few weeks. Yeah, some of the headlines and news articles are over-the-top but most of them are quite good. And the comet in the morning twilight has been fun to photograph.

Comet C/2023 A3 (Tsuchinshan-ATLAS) and Ashurst Lake, Flagstaff, Arizona.
Comet C/2023 A3 (Tsuchinshan-ATLAS) and Ashurst Lake, Flagstaff, Arizona.

I have taken photos on five different mornings over a nine-day period and have captured images of the comet growing brighter and the tail growing longer. On only one occasion was I able to see the comet with the unaided eye. On three occasions I was able to see it with binoculars. On all five mornings it was very easy to capture the comet with even very short exposures on the camera.

The comet is now getting very close to the Sun so I have suspended photography for a few days. When it reemerges in the evening sky I will once again start shooting photos. I hope it is easier to see during this phase.

I shot the comet with a few different focal lengths (50mm, 85mm, and180mm). I think the best images were with the 85mm f/1.8 lens (usually shot at f/2.8) as it gave a wide-enough view to include some foreground.

Here are some photographs and time-lapse video from the period 25 September through 03 October.

25 September 2024

This was my first attempt to photograph the comet. It was taken from the overlook on Mars Hill, home of Lowell Observatory, in Flagstaff. The comet is small and located in the upper middle of the photograph. I often shoot photos of astronomical objects in the eastern sky from this location because I can include much of the city.

Comet C/2023 A3 (Tsuchinshan-ATLAS) and the City of Flagstaff. (25 September 2024)
Comet C/2023 A3 (Tsuchinshan-ATLAS) and the City of Flagstaff. (25 September 2024)

26 September 2024

I was planning on returning to Mars Hill but smoke from a managed wildfire suggested I should try elsewhere. I ended up at the Mormon Lake Overlook. The first image is a stack of 16 images taken over the course of about five minutes. The stacking increases the signal, reduces noise, and allows more stretching of the histogram to pull out the faint details.

The video was taken from the same set of images but without any cropping. The camera was mounted on a star tracker so that the comet remained fixed in the images.

A stack of 16 images taken over the course of about five minutes. (26 September 2024)
A stack of 16 images taken over the course of about five minutes. (26 September 2024)

Time-lapse video of the comet rising above the eastern horizon. (26 September, 2024)

28 September 2024

With some smoke still present I returned to the Mormon Lake Overlook on this morning. I was disappointed at the clouds but afterwards decided that I really liked the image of the clouds partially obscuring the comet tail.

Clouds partially obscure the tail of the comet. (28 September 2024)
Clouds partially obscure the tail of the comet. (28 September 2024)

October 01 2024

I went to Ashurst Lake for this photo session with the hopes of catching a reflection of the comet tail in the calm waters of the lake. I was not disappointed!

In the first image, the comet has not risen above the horizon but the comet tail is strikingly visible in the sky and reflected in the water. In the second image, the comet has barely cleared the trees, the tail is still quite bright, but the reflection on the water has dimmed. Next, the waning crescent Moon rises–and is partially behind a cloud–as the sky brightens making the comet’s tail more difficult to see. The final image is a stack of six images and cropped to show only the comet and tail.

The tail of the comet is reflected in the still waters of Lake Ashurt, near Flagstaff, Arizona. (01 October 2024)
The tail of the comet is reflected in the still waters of Lake Ashurt, near Flagstaff, Arizona. (01 October 2024)
The comet has risen above the trees and the tail remains strikingly visible while the reflection has dimmed.
The comet has risen above the trees and the tail remains strikingly visible while the reflection has dimmed.
The crescent Moon joins the scene in the eastern twilight. The sky has brightened making it more difficult to see the tail. (01 October 2024)
The crescent Moon joins the scene in the eastern twilight. The sky has brightened making it more difficult to see the tail. (01 October 2024)
Close up of the comet and tail in the bright twilight. (01 October 2024)
Close up of the comet and tail in the bright twilight. (01 October 2024)

October 03 2024

My goal on this morning was to shoot a long sequence of images so that I could produce a time-lapse video starting when the comet was below the horizon until twilight became too bright to see the comet. Again, I was at Ashurst Lake hoping for reflections or smooth water. Success!

The first image was taken ~14 minutes before the comet rose above the horizon but the tail is still easily visible.

The comet is below the horizon but the tail extends well up into the twilight sky. (03 October 2024)
The comet is below the horizon but the tail extends well up into the twilight sky. (03 October 2024)

Time-lapse video of the comet rising during the period 0503ā€“0533 MST. (03 October 2024)

As I mentioned at the beginning, there have been many articles about the comet. I think this one from Sky and Telescope is one of the better ones.Ā Also, EarthSky.org has published many beautiful photos of the comet.

The best is yet to come!

North American Monsoon–August 2024

A curtain of light rain from a dissipating thunderstorm is brilliantly illuminated by the setting sun.

Storms in August were more plentiful than in July although there were still some extended breaks in the monsoon. Rainbows remained elusive for me. I was able to photograph a few that displayed short segments but I never captured a full rainbow. Lightning, on the other hand, was plentiful and I did well in that genre.

Here is a partial summary of August monsoon photography.

04 August 2024

Mormon Lake Overlook is a short drive from Flagstaff and affords an amazing 360Ā° view. This was one of the many days with only a partial rainbow but the juxtaposition of the rainbow and the tree in the grasslands of Anderson Mesa was a pleasing composition. A few minutes later the Sun beautifully illuminated some light rain falling from a dissipating thunderstorm. The color was intense and only lasted a few minutes.

A short segment of a rainbow above the grasslands of Anderson Mesa in northern Arizona.
A short segment of a rainbow above the grasslands of Anderson Mesa in northern Arizona.
A curtain of light rain from a dissipating thunderstorm is brilliantly illuminated by the setting sun.
A curtain of light rain from a dissipating thunderstorm is brilliantly illuminated by the setting sun.

Continue reading →

Winter Sunrise

The sunrise after a winter storm often results in beautiful scenery and colors. Low-lying areas may have shallow fog. Mountains may have multiple layers of clouds. All of this is enhanced by the low sun angle as it first rises above the horizon.

Low clouds and fog partially obscure the San Francisco Peaks as the sun rises (24 Jan 2024).
Low clouds and fog partially obscure the San Francisco Peaks as the sun rises (24 Jan 2024).

On the other hand, getting up before sunrise, driving on snow-packed roads, and standing around shooting photos with cold temperatures is a challenge. But the results are often worth the effort. Here are a few sunrise photographs.

Wispy clouds cap the San Francisco Peaks (08 Jan 2024).
Wispy clouds cap the San Francisco Peaks (08 Jan 2024).
First light on some old ranching structures near Mormon Lake (08 Jan 2024).
First light on some old ranching structures near Mormon Lake (08 Jan 2024).
Earth's shadow can be seen behind the San Francisco Peaks in this pre-sunrise image (26 Jan 2024).
Earth’s shadow can be seen behind the San Francisco Peaks in this pre-sunrise image (26 Jan 2024).
Telephoto image of snow and clouds on the San Francisco Peaks (26 Jan 2024).
Telephoto image of snow and clouds on the San Francisco Peaks (26 Jan 2024).
Layers of clouds are draped across Mingus Mountain (03 Feb 2024).
Layers of clouds are draped across Mingus Mountain (03 Feb 2024).

This week should bring lots of snow to northern Arizona. I hope to get some interesting photographs.

 

A Very Foggy Morning

Fog at sunrise in the Mormon Lake Basin.
Fog at sunrise in the Mormon Lake Basin.

A few days ago we had a cold front move across the area and overnight temperatures fell below freezing for a few hours in the higher terrain. It turns out that October is a good month for fog formation from these first frontal incursions. Area lakes still have relatively warm water from the recently ended summer. The passage of the cold air over the warm water allows for increased moisture flux from the warm water into the colder air that increases the dewpoint (and relative humidity) and can result in fog. Also, the shorter days–and longer nights–allows radiation fog to develop in the valleys.

Fog in the Mormon Lake basin with a colorful but diffuse glory.
Fog in the Mormon Lake basin with a colorful but diffuse glory.
A small sailboat lies at anchor on a foggy morning at Upper Lake Mary.
A small sailboat lies at anchor on a foggy morning at Upper Lake Mary.
Fog and Upper Lake Mary.
Fog and Upper Lake Mary.

With that in mind, I found myself driving past Lake Mary to Mormon Lake before sunrise on Tuesday morning. As I approached Lake Mary visibility dropped quickly to 1/4 mile, then 1/8 mile, and then 1/16 mile. Visibility improved once I passed both Lower and Upper Lake Mary. At Mormon Lake, there was fog swirling in the basin and the rising Sun was just starting to illuminate the summits of the San Francisco Peaks.

Fogbow over Upper Lake Mary.
Fogbow over Upper Lake Mary.
Fogbow over Upper Lake Mary.
Fogbow over Upper Lake Mary.

After the fog dissipated in Mormon Lake, I returned to Lake Mary where the fog was still present and I was able to capture fogbows plus a nice photo of a sailboat anchored in the lake.

Time-lapse video of the swirling fog in the Mormon Lake basin.

Time-lapse video of the swirling fog and glory in the Mormon Lake basin.

The time-lapse videos show remarkable motion of the swirling for over Mormon Lake as well as the colorful but diffuse glory that was present.

A very fun morning.


Fog definitions from Weather.gov:

(1) Steam fog (arctic sea smoke). Steam fog forms when water vapor is added to air that is much colder, then condenses into fog. It is commonly seen as wisps of vapor emanating from the surface of water. This fog is most common in middle latitudes near lakes and rivers during autumn and early winter, when waters are still warm and colder air masses prevail.

(2)Ā Radiation fog (ground or valley fog).Ā Radiational cooling produces this type of fog. Under stable nighttime conditions, long-wave radiation is emitted by the ground; this cools the ground, which causes a temperature inversion. In turn, moist air near the ground cools to its dew point. Depending upon ground moisture content, moisture may evaporate into the air, raising the dew point of this stable layer, accelerating radiation fog formation.