I wrote about image formation using a concave mirror in previous posts. One was about virtual images. The other about real images. This time the mirror used is convex. The reflecting surface bulges outward instead of caving inward. You have seen these mirrors in use. A shiny Christmas tree ball-ornament has a convex surface. Stores can have large convex mirrors above the ends of aisles to help avoid collisions. The passenger side mirror of an automobile is slightly convex. “Objects in mirror are closer than they appear”.
We have a decorative convex mirror on our wall. Here is a view of that mirror on the left. The wall shelf unit is visible reflected in the mirror.
Desktop planetarium software helps plan viewing sessions and keep track of the planets and Moon. Many products are available for all computer platforms and smartphones. A browser search yields links to many sources often open source and free. They can be customized to your location and have a nice look and feel. For Android and Mac phones and tablets, I like SkySafari. It isn’t free but is inexpensive. For my desktop computer and laptop, I am a big fan of Starry Night 8 from Simulation Curriculum. It is more costly, but sales are often offered.
If you are near Fairfield Iowa, consider visiting the Maharishi Vedic Observatory. The link is my tour when I visited. There is no large telescope dome. Instead, it is made up of 10 solar and celestial measurement instruments, or sundials, and a collection of inner circles. One is pictured here.
What will the Moon look like on any date in 2025? What will it look like on your birthday? Find out at NASA Dial-a-Moon. An example of what you will see is pictured below for 15 January 2025. The 2025 dates will give a different phase of the Moon. Set dates and see views for readers in the northern hemisphere and for southern hemisphere by following either link. Enter any month and day to see a high definition image. You may leave the universal time (UT) hour at the default value. If you want to be more precise, your local-to-Universal time conversion can be done at this link. Or, type ‘universal time’ into Google. Go back to Dial-a-Moon to enter the UT.
After visiting Dial-a-Moon, scan down that web page for a wealth of additional information about the Moon’s motions and appearance. The images of Dial-a-Moon are made from those of the Lunar Reconnaissance Orbiter (LRO) in low altitude orbit around the Moon since 2009.
I had hopes for clear skies this morning to witness the Moon’s occultation of Spica. Mostly cloudy skies prevented seeing most of the event. An opening in the clouds came by 20 minutes after Spica reappeared and I was able to get this shot.
A larger patch of clear sky was overhead as I waited for the Moon and Spica. A stream of satellites was going over me toward the southeast. I assumed it was a group of Starlink satellites. I saw a similar stream of them two weeks ago. I quickly reset my camera from the Moon and tried to capture some of the stream before they went out of view. The bright star is Arcturus.
The night of 27 Oct 2024 was my last sighting of Comet C/2023 A3 Tsuchinshan-ATLAS. Others with high-end telescopes and equipment will continue to image it for a few weeks. But, it is going beyond the reach of my cameras. I used desktop software that predicted where to look. I tried to see it using 15x binoculars with no success. I put my phone on a tripod with the camera in PRO mode of 3200 ISO and an 8 sec exposure. Only then could I see it…..just barely. This image looks southwest.
It has been fun following the progress of this comet. It was discovered early in 2023 hence the A3 designation. Astronomers soon plotted the orbit and found it would pass very close to the Sun. It was going to rapidly move between Earth and the Sun. After that, no one knew whether it would survive the close encounter or be a brilliant display.
My first view was in late September. I wrote about it in this blog post. It was barely visible to me then. For a few days in the second week of October, the comet passed between Earth and the Sun. It was not visible to us due to the glare of the Sun. But a spacecraft was positioned so it did record the passage. I wrote about that in this blog post.
The comet emerged and has put on a wonderful display to amateur and professional astronomers. Pictures have been posted from all over the world. A blogger friend Bob in British Columbia shared this photo as well as several others.
Rarely does a comet put on a lengthy display like this one. If you missed this one, it will return in 80,000 years. I wonder if any humans will see it.
How I See It 