The Great Conjunction of Jupiter and Saturn

Great Conjunction of Jupiter and Saturn (21 December 2020)
Great Conjunction of Jupiter and Saturn (21 December 2020)

On 21 December 2020, Jupiter and Saturn passed a tenth of a degree from each other in what is known as a Great Conjunction. Great Conjunctions are not rare and occur every 20 years. But the apparent separation between the two planets varies with each event and this one was the third closest in over 800 years (1226 and 1623 were closer) but only one of these was visible; the other was lost in the bright glare of twilight.

Great Conjunction with labels of Jupiter and Saturn (21 December 2020)
Great Conjunction with labels of Jupiter and Saturn (21 December 2020)

The images shown here used a 300mm telephoto lens—which is barely sufficient to resolve the rings of Saturn. The rings can be seen as making Saturn appear oval shaped.

The first image is from 1803 MST on 21 December 2020, just a few hours after closest approach. The second image has labels for the brightest moons of Jupiter and Saturn.

Below is an image showing the daily movement of Jupiter relative to Saturn. It is also easy to see the motions of Jupiter’s four largest moons as they appear in different locations for each of the three Jupiter positions.

Three-day sequence of the Great Conjunction of Jupiter and Saturn.
Three-day sequence of the Great Conjunction of Jupiter and Saturn.

Finally, NASA’s Astronomy Picture of the Day has a very nice image of the two planets. Telescope required.

Crescent Moon Joins Jupiter and Saturn in the Evening Sky

The planets Jupiter and Saturn are drawing closer to each other in the evening sky with each passing day and will be at their closest on December 21st. In the meantime, the crescent Moon moved through the same part of the sky making a nice triplet in the evening twilight.

Here are views from two nights of the Moon, Jupiter, and Saturn.

Moon, Jupiter, and Saturn in evening twilight.
Moon, Jupiter, and Saturn in evening twilight.
Moon, Jupiter, and Saturn in evening twilight.
Moon, Jupiter, and Saturn in evening twilight.

A Thin Crescent Moon Reflected in the Lake

Although it’s fun to photograph the Full Moon, I actually prefer photographing a thin crescent Moon, usually just a day or two after the New Moon. The thin crescent is brightly lit while the remainder is softly lit by light reflected by Earth, hence known as Earthshine. It’s also known as DaVinci Glow. As well, the Moon does not overwhelm the night sky so that stars can also be in the photograph.

A wide-angle view showing the crescent Moon just above the horizon with Venus shining brightly above. The stars of Orion, Pleiades, and Hyades are also visible.
A wide-angle view showing the crescent Moon just above the horizon with Venus shining brightly above. The stars of Orion, Pleiades, and Hyades are also visible.

During late Spring and into early Summer the crescent Moon sets in the west-northwest and this makes it a good target for shooting at Upper Lake Mary. The long and narrow lake is aligned WNW–ESE so that the Moon casts a brilliant reflection that can run the length of the lake.

I’ve shot this several times over the last few years but never tire of it. All it requires is enough of a gap in the clouds for the Moon to shine and for light winds so that the lake surface is relatively smooth.

A zoomed-in view of the crescent Moon with reflection on Lake Mary.
A zoomed-in view of the crescent Moon with reflection on Lake Mary.
As the Moon settles closer to the horizon a thin veil of high clouds adds some interesting texture to the scene.
As the Moon settles closer to the horizon a thin veil of high clouds adds some interesting texture to the scene.

Objects in the Night and Twilight Sky—February 2020

The past few weeks have offered numerous opportunities for photographing objects in the twilight and night sky.

Venus and Mercury in the evening sky.
Venus and Mercury in the evening sky.

Above is a photograph showing the planets Venus (visible near the top of the image) and Mercury (located just below the center of the image). The glow of evening twilight on the horizon is reflected in the shallow waters of Mormon Lake.

Four planets and an asteroid.
Four planets and an asteroid.

Taken later on the same evening is a photograph showing four planets and an asteroid in a single frame. This was taken with a 24mm focal length lens to capture these solar system objects (SSO). I did this as a fun test to see if a wide-angle lens was able to capture these dim and distant SSOs. From top to bottom are the asteroid Vesta, Uranus, Venus, Neptune, and Mercury.

Zoomed-in crops (below) show the dimmer objects that are in the image above.

Zoomed in crops showing Vesta, Uranus, and Neptune.
Zoomed in crops showing Vesta, Uranus, and Neptune.

Before leaving that night I did a final wide-angle shot of the southeastern sky which included the constellation Orion as well as a portion of the winter Milky Way.

Wide-angle view of Orion and Milky Way.
Wide-angle view of Orion and Milky Way.
Pleiades star cluster.
Pleiades star cluster.

The following night I was out again to test my recently purchased Nikon 180mm Ć’/2.8 ED AIS manual focus lens. A few previous tests have shown that star images are pretty good at an aperture of Ć’/2.8 but much better at Ć’/4. At Ć’/2.8 there is just a hint of star spikes; at Ć’/4 they are quite prominent. This is a stacked sequence of images of the Pleiades star cluster. Image stacking was done with Starry Sky Stacker; histogram stretching was done with rnc-color-stretch.

Occultation of Mars.
Occultation of Mars.

On 18 February there was a Lunar occultation of the planet Mars. I had planned to get up early and drive to a dark location but an alarm failure meant I barely had time to get up and set up the gear on the rear deck of the house to start the sequence. Luckily, Flagstaff is a Dark Sky City and it was dark enough to get the shots. This is a sequence from just a few minutes before the Moon moved in front of Mars followed by a longer sequence after it reappeared.

Comet C/2019 Y4 (ATLAS)
Comet C/2019 Y4 (ATLAS)

Finally, Comet C/2019 Y4 (ATLAS) is in the northern sky making it an easy target—except that it is still very dim with a magnitude of about +12 at the time of this image. The still image is a stack of 49 images each 120 seconds duration at ISO 1600, 180mm, and Ć’/2.8. As noted above this lens is pretty good at Ć’/2.8 but better at Ć’/4. Because the comet is so dim I wanted the maximum light gathering ability so settled for an aperture of Ć’/2.8. Also in the image is M97 (“Owl Nebula”) and M108 (“Surfboard Galaxy”). The star Merak is part of the “Big Dipper.”

Also, there is an animation—made from the same images—showing the movement of the comet over a period of just under 2 hours.

Moonrise over Wukoki Pueblo

Moonrise over Wukoki Pueblo, Wupatki National Monunent.
Moonrise over Wukoki Pueblo, Wupatki National Monunent.

Wukoko Pueblo in Wupatki National Monument is an amazing place. Here is what the National Park Service has to say about the pueblo:

An architect today might win an award for designing Wukoki Pueblo. The corners, angles, and lines of masonry are meticulous. From its base, the eye is drawn skyward to a height that inspires awe of this ancient craftsmanship.

The architecture blends so well with the environment that the building seems to grow out of the rock, disguising where nature’s work ends and handcrafted walls begin. Today these walls stand as a silent tribute to prehistoric people.

I have visited this site many times capturing the Milky Way above it, lightning around it, and sunsets. But I’ve never had a chance to capture the rising [nearly] full Moon until yesterday. The terrain is such that the best time of the year is December when the full Moon is farthest north in the sky. At other times of the year, nearby hills obstruct a view of the Moon until it has risen high in the sky. Even in December, the distant Tloi Eechii Cliffs rise above the horizon. But in this case, they add to the drama of the rising Moon. This was taken the day before the full Moon so that the late afternoon sun could still light up the landscape and the pueblo.