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Measuring the Cosmos: A Hazy Night with Lyra the Harp

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Often, when amateur astronomers gather under the stars, the conversation turns to size and distance. We might say a planet looks incredibly tiny, or note that two stars seem to be sitting right next to each other. But how do you measure the sky? You can’t exactly hold a tape measure up to a constellation. Instead, astronomers use something called angular measure to describe how big or how far apart things look from our perspective on Earth. To understand how this works, imagine the night sky as a giant, transparent sphere. We are standing right at the very center, looking out. Even though stars, planets, and galaxies are actually at vastly different distances from us, they all appear to be glued to the inside of this bubble. Astronomers call this the celestial sphere. If you were to draw a line on the inside of this sphere that went all the way around the Earth and back to your starting point, it would form a perfect circle. Like any circle, this one can be divided into 360 degrees. So...
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Observing in Ursa Major

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When we look up at Ursa Major, the Great Bear, we’re seeing a constellation that barely rises above the horizon in much of the southern hemisphere. But from mid-northern latitudes, Ursa Major is a year-round presence—one of the most easily recognized constellations in the sky, thanks to the prominent asterism known as the Big Dipper. That familiar pattern of seven stars—Alkaid, Mizar, Alioth, Megrez, Phecda, Merak, and Dubhe—has featured in sky lore for thousands of years. Many of its stars are physically related, part of the Ursa Major Moving Cluster—a collection of stars that formed together and still travel through space in the same general direction.* I was thinking of all these things while observing one moonlit night. The sky wasn’t ideal—washed out by city lights and a nearly full gibbous moon—but I set up my 203mm Dobsonian reflector anyway to take a look around.  Observing in Ursa Major The Big Dipper hung just above the trees to the north, and I backed up against the shed...
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Moon Photos

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These are my cell phone photos taken through a 203mm telescope, zooming in on successive shots. The last image identifies craters by name. Things to notice: 1) Sinus Iridum is partly buried. 2) Rays of brighter material fan out from Kepler Crater. 3) A mountain peak within Lansberg Crater is visible in close-up. I took these photos during the morning of March 27, 2025.
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The Brightness of Stars

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The night sky, when viewed from a dark rural location on a clear evening, is a spectacle of stars. Some of these stars shine quite brightly, forming familiar constellations such as Orion the Hunter, or creating distinctive shapes like the Summer Triangle. Other stars shine less brightly. The individual brightness of a star is determined by a combination of how much light it creates and its distance from Earth. These two fundamental characteristics result in varying levels of brightness among the stars we observe. To quantify and describe the brightness of stars, astronomers use the concept of magnitude. Magnitude and its Logarithmic Scale The magnitude of an astronomical object refers to its apparent brightness as observed from Earth. Historically, the ancient Greeks called the brightest stars first-magnitude stars, with the dimmest visible stars described as sixth-magnitude stars. Magnitudes 2, 3, 4, and 5 fell in between. The key takeaway from this early classification is that the lo...
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Lunar Eclipse Photos

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Here are my photos of a lunar eclipse through varying clouds. It was nice to watch even though I couldn't get a clear sky image.  I took the photos on March 14, 2025, using a cell phone camera on a 203mm Newtonian telescope.
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Planetary Neighbor

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A fellow amateur astronomer and I, both members of the Auburn Astronomical Society, headed to scout camp with our telescopes to share the night sky with several dozen Cub Scouts and their families on a perfect, moonless autumn evening. Our purpose was to introduce them to the cosmos in a new way. I set up my telescope, focusing on the evening’s highlight: Saturn. Meanwhile, my colleague aimed his telescope at Vega, a bright star positioned high in the sky. Though we had only two objects in our lineup, each had a story. As the families trickled in, my counterpart welcomed the first few kids to his telescope. Vega didn’t reveal much detail; stars, even seen through a telescope, tend to look like brighter versions of themselves. But my colleague was well prepared to share Vega’s story. He explained that it was about 25 light-years away and described what that distance meant—light that had left Vega 25 years ago was only just now reaching us.    The group then made their way to m...
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An Introduction and Observing the Seedling

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In the summer of 2022, I started a podcast called A Backyard Astronomer's Diary as a creative outlet. The podcast ran for ten episodes before I ended production. The reasons I ended it were twofold: first, it was taking me two months to produce an episode—too slow to effectively build an audience. Second, I wasn't satisfied with how my scripted approach worked in audio format. I decided the scripts conveyed their content better in written form. The first episode, presented as a written piece, is shared below. I've included the original illustrations that I made for the podcast website. I'll be editing and posting excerpts from additional episodes in coming weeks. Enjoy! A Backyard Astronomer's Diary, Episode One: An Introduction and Observing the Seedling Greetings from Montgomery, Alabama, USA. This is A Backyard Astronomer's Diary with Jim Harstad. In this episode: An Introduction and Observing The Seedling. I'm an amateur astronomer. I'm not a profess...
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