Tag: conjunction

Moon-Venus Conjunction

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A few days ago, the thin crescent Moon passed close to the planet Venus in the evening twilight sky. Conjunctions such as this repeat at roughly one-month intervals so this is not a rare occurrence—just a beautiful one.

Conjunction of Venus and the Moon.
Conjunction of Venus and the Moon.

The crescent Moon is ~2.4% illuminated by the direct light of the Sun; the remainder of the Moon is lit by Earthshine which is bright enough to show detail on the shadowed face of the Moon. Leonardo da Vinci explained the phenomenon in the early 16th century when he realized that both Earth and the Moon reflect sunlight at the same time. Light is reflected from Earth to the Moon and back to Earth as earthshine.

Conjunction of Venus and Mars

As mentioned in the previous post, the planets Venus and Mercury passed very close to each other in the evening twilight sky a few nights ago. In fact, this conjuction is the closest conjunction of these two planets until 2033. I chose to photograph the two planets the night before closest approach as I was interested in getting a bit of separation of the two in both the sky and their reflections in the water.

Venus and Mercury in evening twilight (2025 MST 27 May 2021).
Venus and Mercury in evening twilight (2025 MST 27 May 2021).
Venus and Mercury in evening twilight (2037 MST 27 May 2021).
Venus and Mercury in evening twilight (2037 MST 27 May 2021).

The first image was taken at 2025 MST 27 May 2021 with an 85mm focal length. The second image was taken a short time later at 2035 MST with a focal length of 120mm.

In the first image, there is a very nice and long reflection of Venus in the water; the reflection of Mercury is also present but is faint and diffuse. In the second image, the planets were just a few minutes away from dropping below the ridge to the northwest. In this image, the reflections of both planets are easily seen.

The weather cooperated nicely with light winds allowing reflections on the smooth water of Upper Lake Mary.

 

Conjunction of Mars and Uranus

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.

Mars and Uranus in the evening sky
Mars and Uranus in the evening sky

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

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.
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.
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.

Venus and Pleiades Conjunction—April 2020

During the first few days of April 2020 the planet Venus moved towards and then through the Pleiades star cluster. Venus and Pleiades have a conjunction every year but every eight years the conjunction is at its closest. This year, Venus moved right through the star cluster.

Conjunction of Venus and Pleiades
Conjunction of Venus and Pleiades

I shot images of Venus and Pleiades on three nights: 01 April, 03 April, and 05 April. Venus and Pleiades were closest on the night of 03 April. I then did a composite image of the three nights showing the progression of Venus past the star cluster. These were all shot at 8 seconds, f/4, 180mm, and ISO 800.

Additionally, I overlaid another image taken 13 February 2020. This is a stacked composite with 11 images shot at 120 seconds, f/4, 180mm, and ISO 1600. The images were stacked using Starry Sky Stacker. The stack was then post-processed using rnc_color_stretch. This composite image was used because it shows the nebulosity and color within the Pleiades better than the shorter exposures captured that show the motion of Venus.

Composite image of Venus and Pleiades.
Composite image of Venus and Pleiades.

The image above shows the composite from the three nights without the additional layer showing the nebulosity.