The weather forecast for today predicted over an eighty percent chance of rain so I either needed to make my observation before midnight or wait a couple of days for cloudless skies. Fifteen minutes before my Mythgard Academy class started last night (at nine o’clock Central Time), I decided to make my first observation. I set the timer on my smartwatch for ten minutes and hung outside while my neighbors to the north decided a fire in their firepit was warranted (not helping my light pollution survey one bit). My neighbor to the south also appeared to have search lights trained on my backyard so adjusting my eyes for optimal viewing already had steep hills to climb. I somewhat patiently waited for the timer to count down.
Meanwhile, I found Venus immediately, very high and extremely bright in the west. Next, both Procyon and Sirius shown brightly in the upper and lower southwest. Even though the sun had set over an hour ago, the western sky still seemed dimly luminescent and I detected a very slight haze obscuring the fainter stars. My timer buzzed and I began sketching out the brightest stars and the only constellation I could identify – Orion – sinking slowly into the southwestern horizon. To the north I could just barely make out Polaris but could not find the Big or Little Dipper (mostly because the trees are starting to leaf out).
Almost directly overhead but still on the eastern side of the zenith, I could barely make out a sickle, an asterism that can be found in the constellation Leo (see diagram below). I had checked the Sky and Telescope Interactive Star Chart before stepping outside so I knew where to crane my neck in the hopes of spotting the lion. In addition to the sickle, I could also make out, barely, the triangle of stars that form the lion’s rear and tail. I could not tell where Leo ended and Virgo began as the stars were so faint I gave up.
I returned to my computer, logged into the Webinar and while I waited for it to start, I verified my sketch against the star chart. I had found Leo, but only by the very brightest of it’s stars (which aren’t that bright when you compare them to Sirius, Vega or Procyon). Fast forward two hours, where I found myself nodding off and decided I’d consumed enough First Age elven antics for one session and bailed out of the webinar (I can always watch the last 15-30 minutes via YouTube later).
I went back outside and noticed immediately the haze had disappeared. The air was crisper and I didn’t even need to wait the full ten minutes before I could clearly see the constellation Leo, now slightly west of top-dead-center overhead. My northern neighbors were still enjoying their outdoor fire but my southern neighbors had toned down the search lights to just one very bright LED porch light.
I returned inside and recorded both of my observations via the Globe at Night web site. I plan to repeat my observations each night weather permitting until the middle of next week.
I can take good advantage of this occultation since I live in the middle of the country just shy of 40 degrees north latitude. If I were visiting my daughter in the Pacific Northwest, I’d have a bit more dark time but might not see it as well being at a more northern latitude at 47 degrees.
Actually, not just Mars will be in the spotlight in mid-February. Three planets are center stage in the predawn skies starting February 18th (see first graphic above). Listen to Sky Tour courtesy Sky & Telescope for some viewing tips and other astronomical tidbits for February observing.
My only concern will be the weather, which in February in Kansas, is dodgy at best.
Keeping my fingers crossed and as always keep looking up!
Enjoy the shortest day of the year because I’m looking forward to the longest, darkest night of the year – every amateur astronomers dream.
Today, my son, daughter-in-law and grandson are driving here from Texas. They left before dawn and we anticipate their arrival late this afternoon.
With the help of my daughter, who arrived earlier this week, my main floor living area is mostly baby proof. And the new furniture was delivered Thursday afternoon. And Friday, Rachelle setup the Christmas tree and last night over home-made pizza we decorated (or rather she decorated because she’s the artistic one).
Rachelle and I will spend part of the day shopping, taking advantage of her Costco membership to stock up on food she can eat (corn allergy) and for the rest of the family as well. While I have a Christmas goose in the freezer, I need to plan for other meals and sides. Instead of just Terry and I to feed, I’ll have three to four times that many to provide for.
So we are ready for family gathering and making new memories until we once again scatter back to our nests for the new year.
These are a few of my favorite things during the winter months and they add up to darker skies and brighter stars. This weekend also has a few things going for it, astronomically, and also happens to be Twelfth Night (tomorrow, January 5th) and Epiphany (the day after) commemorating the journey of the Three Wise Men guided by a Star in the East.
Friday, January 4
Although people in the Northern Hemisphere experienced the shortest day of the year two weeks ago (at the winter solstice December 21), the Sun has continued to rise slightly later with each passing day. That trend stops this morning for those at 40° north latitude†. Tomorrow’s sunrise will arrive at the same time as today’s, but the Sun will come up two seconds earlier Sunday morning. This turnover point depends on latitude. If you live farther north, the switch occurred a few days ago; closer to the equator, the change won’t happen until later in January.
† I’m just 68 miles south of the Kansas-Nebraska border, which juxtaposes with the 40th parallel. Weird fact discovered this morning via Google Maps: The Kansas Highway that is literally a block west of my house (K-7) ends at the border and turns into 666 Avenue (see map screenshot below). Continue reading “There’s a Star in the East”
I’ve reached the halfway point through my Introduction to Astronomy class. This week marks the eighth week of fifteen, sixteen if you count the first week where we just spent time getting to know each other and exploring the textbook and getting the lab software, Starry Night, installed and licensed. Last week, we reached the outer limits in the Kuiper Belt and Oort Cloud of our solar system where only comets and Voyagers I and II have ventured. Now we’ve snapped back to study our closest star, Sol, or more commonly just the Sun. My topic for discussion responds to the following question:
Why is the solar cycle said to have a period of 22 years, even though the sunspot cycle is only 11 years long?
Some surface features on our active Sun vary periodically in an eleven year cycle. The Sun’s magnetic fields which cause the surface changes vary over a twenty-two year cycle. The relatively cool and slightly darker regions, commonly called sunspots, are produced by local concentrations of the Sun’s magnetic field piercing the photosphere. The latitude and number of sunspots on average vary during the same eleven year cycle. But the hemisphere where the Sun’s north magnetic pole anchors during one eleven year cycle will have south magnetic poles during the next. Because it takes a full twenty-two years for the magnetic poles to return to their original orientation astronomers refer to the entire solar cycle. The magnetic dynamo model posits that many transient features of the solar cycle are caused by the effect of differential rotation and convection on the Sun’s magnetic field. The Sun’s differential rotation (different speeds at different latitudes) causes its magnetic field to become increasingly stretched like a rubber band. The bands can’t break so they periodically untangle themselves with the help of trapped gases which leak out (sunspot) and gradually settle back under the photosphere, when the sunspot disappears. The most recent reversal of the Sun’s magnetic field occurred in 2013. We are currently at the tale end of Solar Cycle 24. (Comins, 2015, p. 272-83)
My topic for discussion this week will attempt to answer the question:
Why do astronomers believe that the debris that creates many isolated meteors comes from asteroids, whereas the debris that creates meteor showers is related to comets?
But first, I want to share two things that serendipitously fell from my Twitter feed (@mossjon) today. Today’s APOD (Astronomy Picture of the Day@apod) featured the unusual mountain on Ceres (Comins, 2015, p. 239).
The second thing that immediately caught my eye today was an episode of Astronomy Magazine‘s “The Real Reality Show” entitled “How an Asteroid Killed Off the Dinosaurs” covered late in Chapter 8 of our textbook (Comins, 2015, p. 263-4) and which also bonked me on the head via my Twitter feed:
In this week’s discussion topic, I attempt to answer the question “Why are Uranus and Neptune distinctly bluer than Jupiter and Saturn?”
On Uranus and Neptune, the methane absorbs red, orange and yellow light, reflecting back the blue. In contrast, Jupiter and Saturn have only minor trace amounts of methane and quite a bit more hydrogen and ammonia.
On the basis of lunar rocks brought back by the astronauts, explain why the maria are dark-colored, but the lunar highlands are light-colored?
Regions of both the near side and far side of the Moon not covered by mare basalt are called highlands. The highlands consist of the ancient lunar surface rock, anorthosite, and materials thrown out during the creation of the impact basins. (“Lunar Rocks | National Air and Space Museum,” n.d.)
The anorthosite rock highlands are brighter than the maria basalts. Pulverized by meteoric action, both the basalts of the maria and the anorthosite of the highlands are covered by a blanket of powdered rock, also known as regolith. Continue reading “Dark Seas and Bright Highlands”
Long answer: Still Jupiter, but let’s dive in and take a more detailed look.
Birth of a Gas Giant
A long time ago in a solar system very near you, just 1 or 2 AU past the snow line, enough surrounding planetesimals were accreted to become an Earth-like body containing about ten (10) Earth masses of metal and rock. This, in turn, gave this massive body enough gravitational attraction to pull vast amounts of hydrogen, helium and ices near its orbit, creating the first planet in our solar system: Jupiter. Impacts from the infalling gases and ices heated Jupiter up, so much so that for a short time, it outshown the protosun, if viewed from equal distances. Jupiter lacked the total mass to become a star, needing to be seventy-five (75) times more massive to achieve the necessary compression and heat in its core to sustain fusion.
My second post in my series of weekly discussion topics for my Introduction to Astronomy online class. Last week I got up close and personal with the many sides of the Moon. This week I take a closer look at the other blue planet in our solar system and how we discovered it without observing it first.
Why was the discovery of Neptune a major confirmation of Newton’s universal law of gravitation?
Before Newton, astronomy relied on observational data from which mathematical formulae and equations were created. Newton pioneered an approach which allowed mathematicians to extrapolate and predict the movement of objects using three assumptions, now commonly known as his laws of motion. Together with his formula for gravitational force, Newton transformed Kepler’s three laws to predict orbits of comets and other solar system objects. He further formulated a mathematical model, known as the Law of Universal Gravitation, that describes the behavior of the gravitational force that keeps the planets in their orbits. (Comins, 2015, p. 42-44)