kosmikaastronomy

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This beautiful photo is of the Rho Ophiuchi cloud complex, one of the most colorful and active star-forming regions in the visible universe.

Somewhat contrary to the original post's caption, this isn't a single nebula but rather a group of nebulae. This particular photo captures Lynds 1688; the largest and most active section of the complex. It's a dark nebula, meaning it doesn't emit or reflect visible light like other nebulae. It's body is so dense that it blocks light from stars and other objects behind it, causing it to appear a "dark" nonvisible void. (The original captioning may be misleading as the complex is made up of multiple nebula including those that reflect or emit visible light).

Now you may be thinking, if it's a dark nebula, why is this picture so colorful and detailed? It very clearly shows the formation and discernable details, not very obscured or dark at all.

This is because of false coloring.

Because dark nebulae block/absorb visible light, astronomers use telescopes that capture different wavelengths of light that give us a clearer picture. In particular, I recognize this image from NASA's WISE telescope, WISE standing for Wide-field Infrared Survey Explorer, a telescope that specially took infrared pictures.

The colors present are due to false coloring, which as I mentioned in my last post is a common technique in astrophotography that's useful for several reasons. Here, it allows us to perceive and visualize lengths of light that are not visible to the human eye.

In this image, blue and cyan coloring represents light of wavelengths 3.4-4.6 microns, mainly emitted by stars. Green and red represent wavelengths 12-22 microns, that mainly come from the dust of the nebula itself.

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Sources: WISE Unveils a Treasure Trove of Beauty & Dark Nebula Swinburne University

image: NASA/JPL-Caltech/WISE Team

The Rho Ophiuchi cloud complex is a dark nebula.

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What Is a Sturgeon Moon?

If you're in astronomy circles online, chances are you've heard a lot about the recent Sturgeon Moon. While this year's Sturgeon Moon has already passed, beautiful photos like the one above, are still circulating and capturing awe and buzz online. So, I figured why not talk a bit about it?

A Sturgeon Moon refers to the full moon during the month of August. The name comes from the Algonquin people, an indigenous group who lived near the great lakes and noticed that sturgeon were especially plentiful during August. Although I can find no information supporting specifically August being an abundant time for sturgeon, sturgeon are migratory fish and August may align with the time sturgeon return from spawning in rivers in spring and early summer.

Cool as that is, the Sturgeon Moon isn't the only name that Native American groups gave to the August moon:

Anishinaabe people call the month manoomin dabik-giizis, meaning the "wild rice moon" (Moon being in reference to a month on the lunar calendar). This is because August is when the native marsh rice, manoomin, ripens for harvest.

The Assiniboine call the Sturgeon Moon the Black Cherries Moon in reference to the ripening of chokecherries. And even on the west coast, the Tlingit people in Alaska call it the Mountain Shadows Moon after the harsh shadows created by the full moons light.

 While the colors on the photo above look especially beautiful and colorful, it should be noted the Sturgeon Moon does not have any special visual phenomena besides being the full moon. The colors are due to false coloring and filters which are commonly used in astrophotography.

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photo : Ildar Ibatullin

[kosmikaastronomy]

Ghostly Cloud NGC 1788: the Cosmic Bat in Orion © ©

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Great star gazing opportunity for those in the northern hemisphere!

✨ Don’t sleep tonight! ✨ The Perseid meteor shower is peaking tonight (Aug 12–13) 🌠 — one of the brightest, most reliable meteor showers of the year.

🔭 When to watch: After midnight for the most activity 📍 Where to look: Northeast toward Perseus (but meteors can streak anywhere) 🌌 Best viewing: Far from city lights 🌕 Heads up: The bright moon might wash out faint meteors, but those brilliant fireballs? Still totally worth staying up for.

Bundle up, bring a blanket, and get ready for nature’s own fireworks show. 💫

[kosmikaastronomy]

What does "Retrograde" mean?

You've probably heard the term "retrograde", likely in conjunction with the planet Mercury. But have you ever wondered what it really means when a celestial object, or anything for that matter, is in retrograde?

Firstly, retrograde refers to anything, although especially planets, moving backwards. You or I could technically be in retrograde if we moon walk! But when someone says, for example, "Mercury is in retrograde", they're describing the visual phenomenon of Mercury appearing to "moonwalk" or move backwards throughout the night sky. Crazy right? Is Mercury, or any object, literally moving in reverse?

Before you start worrying your head about the implications and consequences of such odd motion, the answer to the previous question is no. Celestial objects (or planets at least) do not literally move backwards.

This visual effect is called apparent retrograde motion, meaning the planet only seems to move backwards from one's perspective on Earth. In reality, it continues its orbit in a normal forwards fashion. This illusion is caused by differing and relative speeds of Earth and other celestial bodies as they orbit the Sun.

Earth takes 365 days to orbit the Sun, but Mercury circumnavigates the Sun in 88 days. As Earth catches up to Mercury (who you can think of as having "lapped" Earth in a track race) and looks back at Mercury, it creates the illusion that it is moving backwards in the sky.

Here is a helpful visual explanation!

[kosmikaastronomy]

Robert Gruszecki

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M4 / Spider Cluster

This bright splattering of light is called M4, short for messier 4, but colloquially (casually) called the Spider Cluster.

The Spider Cluster is a globular cluster, meaning a large grouping of stars, in this case upwards of 100,000.

M4 is unique for a couple of reasons. 1, it's my favorite globular cluster. 2, it's the closest GB to our solar system- only 5,500 light years away! 3, it's home to some of the oldest stars in our universe, with some up to 13 billion years old (which is also super cool because it gives us a better idea of the minimum age of our universe).

M4 makes a great amateur stargazing target as its pretty easy to find in the night sky (if you're in the northern hemisphere that is). Look for Antares, the bright red star in the middle of Scorpio, and look slightly up and to the right. It's usually visible as a bright blob in binoculars and as a cluster in 4 inch telescopes. Due to how close it is it's very bright with an (apparent) magnitude of 5.9.

M4 is most visible in the summer months with June through July being optimal viewing months.

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photo credits: La Silla Observatory 

citations: https://science.nasa.gov/mission/hubble/science/explore-the-night-sky/hubble-messier-catalog/messier-4/

[kosmikaastronomy]

Welcome to my corner of space!

I go by Kosi, and I love Astronomy!

My credentials are too much time surfing the internet and some years operating a small observatory. This blog exists to make physics, especially astrophysics, accessible in an easy to understand format (And also just to spread cool astronomy news and images I stumble across). Feel free to ask questions or request certain kinds of posts (star gazing guides, astrophotography / astrophotography guides, general physics questions and studies). I'm a total nerd and would love to answer them!

Every Monday is Object Monday where I post about an observable celestial object for stargazing. (posted under #COMonday)