Conjunction of Mars and Uranus

January 19, 2021 / Add comment

The planets Mars and Uranus will at their closest in the evening sky on 20 January 2021. Unfortunately, the Moon will also be very close to these two planets which could make it difficult to see Uranus. Mars, however, is bright enough to be easily viewed even with the Moon. Currently, Mars has a magnitude of 0.16 while Uranus is considerably dimmer at magnitude 5.76 — making Mars ~175 times brighter than Uranus.

I chose to shoot the two planets a few days early to avoid any issues with the Moon and clouds from an approaching winter storm. Besides, the appearance a few days either side of the date of conjunction would not look too much different.

Mercury, Jupiter, and Saturn in the Evening Sky

January 12, 2021 / Add comment

A few weeks ago Jupiter and Saturn passed very close to each other during the Great Conjunction of 2020. Jupiter and Saturn are now pulling away from each other and are lower in the southwestern sky—but they have been joined by Mercury resulting in a planetary triplet viewable in the twilight.

Mercury, Jupiter, and Saturn in the evening sky.

This is a composite of three images taken over successive nights (09–11 January 2021) that shows the relative motions of the planets Mercury, Jupiter, and Saturn in the southwestern sky. The images have been aligned using Saturn as an anchor point.

Mercury, Jupiter, and Saturn on 09 January 2021.

From this composite, one sees small daily motions of Jupiter as it continues to move eastward away from Saturn—which had their Great Conjunction on 21 December 2020. Mercury exhibits large daily eastward motions as it races toward its greatest eastward elongation on 24 January 2021.

Winter Sunrise on the San Francisco Peaks

January 1, 2021 / Add comment

A weak winter storm brought small amounts of snow to northern Arizona earlier this week. Storms have been rare this autumn and winter so I was motivated to shoot some sunrise photographs.

Early morning sunlight illuminates new fallen snow on the San Franciso Peaks.

A look at satellite imagery early in the morning showed that clouds were still plentiful across a lot of the area except that there was a broad clearing to the east. This meant that the sun had a chance to shine on the peaks as it was rising.

And it did. For about eight minutes the sun illuminated the peaks and new snow. And then, as it rose higher, it was obscured by clouds and the morning light disappeared.

It was brief. It was cold (-9C, 16F). It was worth it.

The Great Conjunction of Jupiter and Saturn

December 23, 2020 / Add comment

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)

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.

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

December 18, 2020

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.