During April 2022, the morning predawn sky had Venus, Saturn, Mars, and Jupiter in various alignments. In the last days of April, Jupiter approached Venus and closed the angular distance between them as seen from our perspective on Earth. This short video shows the locations of the planets as time is stepped forward from 27 April to 4 May. Notice how Earth, Venus, and Jupiter are nearly along the same line of sight at the middle of that time interval.
I hoped to get an image of Venus and Jupiter on 30 April when they were at their closest angular distance of about 0.3˚. Our Moon’s diameter in the sky is only 0.5˚. But, cloudy skies during that time prevented any sight of the pair. Today, 4 May, the sky was finally clear. I got a good image of Jupiter well past and to the right of Venus. This composite aligns today’s image with 3 previous images.
I assumed someone in the world had a clear sky on 30 April and got an image of the two planets together in the same field of view of a telescope eyepiece. I check daily for interesting astronomical images on Spaceweather Gallery. There I found an image by Particio Leon in Santiago, Chile, taken at 11:27 am local time. They displayed differences in size, phase and surface brightness. He used a Canon Canon EOS Rebel T7i through his 8″ telescope with settings of f/6, 1/320s, and ISO100. I took the liberty of rotating his image to simulate my view from the northern hemisphere if I had been able to witness it myself.
The Moon was watching from below as Jupiter and Venus neared each another. This view was at 5:40 am local time. The closest approach for the two planets is Saturday 30 April. They will be separated by less than the width of our Moon. Get up and see it if you have clear skies.
Two days ago, I viewed Venus as it crossed the meridian to the south at 10:26 am. I attached an old smart phone to the eyepiece in order to confirm settings and setup. It was an easy target. Image quality was not very good. But, it worked.
I tried to image Jupiter as it passed the meridian at 11:00 am and didn’t succeed. I could see it with my naked eye. But the camera didn’t capture it. Removing the phone adapter to look through the eyepiece and then returning it for an image disturbed the alignment.
Venus has been a prominent early morning sight for several weeks. If you are an early-riser and look low toward east, you can’t miss it. It will be there until late summer or early fall. Less obvious in the same part of the sky are the planets Saturn and Mars. On 28 March 2022, the clear predawn sky even presented a thin crescent Moon below this grouping of those planets.
On successive mornings, Saturn and Mars approached closer to each other. This view on 3 April 2022 was photographed through a living room window. The green thing is a glass ornament. This was the only unobstructed viewpoint due to trees and rooftops.
It was a rainy morning on April 4. But, the sky was mostly clear on the 5th. Saturn and Mars were at their closest approach less than the diameter of a full moon.
Keep watching that part of the sky to the lower left of Venus. Jupiter will begin making an appearance. On 18 April 2022, these four planets will form a straight line like this.
The four largest moons of Jupiter are Io, Europa, Ganymede, and Callisto. First seen by Galileo Galilei in December 1609 or January 1610, he described them as satellites in orbit of Jupiter in March 1610. They are easily seen near the planet using a simple telescope or a steadied pair of binoculars. They are currently well placed with Jupiter in the evening sky to the southeast soon after sunset.
Imagine being high above Jupiter looking down at the planet and the four moons. Desktop planetarium software is very helpful here. In this view, Jupiter is centered. The Sun is far to the left off-screen. The moons are labeled in each of their orbits. The fastest is Io closest to Jupiter. Callisto is the slowest. Three of the moon have shadow lines drawn in orange. Play the video and watch their movements. The shadows cast by each of those three moons are intercepted by Jupiter. The software speeded up the rate many times.
What would this event look like for viewers on Earth? Earth would be located far off-screen to the left toward the Sun. Could we see the shadows cast by the moons upon the cloud tops of Jupiter? Again, software can simulate the view accurately. The answer is yes. Earthlings with powerful amateur telescopes are capable of seeing the shadows.
Play the video and watch for several things in this simulation. The first is Callisto casting its shadow on Jupiter. Over the course of several hours, it moves across the entire face of the planet. Next, Ganymede and Europa approach from the left. At 24 sec in the video, both of their shadows are cast. Also, Callisto’s shadow moves off the planet and the moon Io disappears into the shadow of Jupiter just off the right limb of the planet.
Watch at the 30 sec time how Europa is occulted by Ganymede. Both shadows are still visible but they become one briefly at the 32 sec mark. Finally, at 38 sec, both moons and their shadows are off to the right. Did you notice how Io emerged to the left of Jupiter in the distance? You might need to view both of these videos a few times.