Time for another physics lesson in optics. Using the small concave 3″ mirror in a previous post, light rays from a window were directed at it from about 10 meters away from across the room. I asked my assistant to stand in front of the window with her arms up so her outline was visible. The rays reflected off the concave surface of the small round mirror in the foreground and formed a small image of her in the window on a piece of white paper standing in front of the mirror. Her image on the paper card is very reduced in size and hard to see.
During the evening of 23 May 2023, the Moon was located near the planets Venus and Mars. Close by were the stars Pollux and Castor of Gemini. It was a grouping worthy of a photograph.
~9:30 PM local time | 23 May 2023 | Canon PowerShot SX60 HS | J. Ruebush
I wondered how the approach of Venus toward Mars would look during the coming nights and weeks. With desktop planetarium software I simulated the view using Pollux and Castor as a frame of reference. This screen grab shows the movements of the planets toward the upper left on several consecutive nights at about 9 pm.
Starry Night Pro 8
Clear skies on the following consecutive nights allowed me to record the scene a total of 7 times. I used software to layer the images onto each other. Each image was adjusted so that Pollux and Castor were superimposed as the frame of reference. Progress of Venus and Mars relative to Pollux and Castor was very obvious. Their orbital motions carried them toward the upper left each night. More commentary about their progress is in this previous blog post.
~9:30 PM local time | Canon PowerShot SX60 HS | J. Ruebush
Venus neared Mars due to its faster orbit and nearness to Earth. It became harder to photograph this scene each night as the stars Pollux and Castor moved lower toward the western horizon and they moved behind some trees near my vantage point. In order to continue photographing the progress of the planets, I needed to use another set of stars as a frame of reference. The constellation Leo was to the upper left. So, each clear night I included Regulus and gamma 1 whenever I shot the two planets. Here is an example.
The Moon posed with Venus, Mars, Regulus and gamma in Leo last evening about 9:41 pm CDT. It was over exposed in order to see the dimmer planets and stars. A second photo zoomed in on the Moon and adjusted for exposure.
Weather in the middle of the US has been unusually good for astronomy for more than a week. But, not so good for those who grow things. The forecast discussion yesterday used the term ‘flash drought’ to describe the worsening conditions. No general relief is in sight. The clear skies and dry air are welcome conditions for those of us who look upward.
Back on May 23rd, the forecast called for several days of clear skies. I’d been watching Venus in the evening as it moved below the stars Pollux and Castor and as it moved closer to Mars to its upper left. Each night for a week at about 9:30 I aimed my camera at the scene and captured a series of 7 images from the 23rd to the 29th. I used image editing software to layer those images in order to show the movements of Venus and Mars as they moved toward the upper left. Each image layer was centered on Pollux and Castor as reference points in the sky. The Sun is well below the horizon out of view to the lower right of the image frames.
~9:30 PM local time | Canon PowerShot SX60 HS | J. Ruebush
In the video below, Mars (orange) being far from the Sun is in a slower orbit. Its daily movements are smaller than those of Venus (grey). Venus is much closer to the Sun and in a faster orbit. It will eventually make the turn in its orbit and pass the Earth (blue). The date of greatest elongation angle of Venus from the Sun is June 4th this year. From our point of view on Earth, Venus will stop getting nearer to Mars and appear to reverse direction across the sky as it passes the Earth. I hope to capture some images as Venus reverses course and update this post. It will become a morning planet in the late summer and fall months.
Last night at about 10 the space station passed overhead. It was a chance to see it pass near Venus and Mars plus the stars Pollux and Castor of the Gemini twins. The iPad app Nightcap captured the scene including 3 airplanes. Their trails completed a trapezoid in the sky during the 147 sec exposure. That was an interesting surprise.
Taken with NightCap, ISS mode, 147 sec exposure, 1/2 sec shutter speed.
How I See It 