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- Luke
- Jun 1, 2022
- 16 min read
Updated: Jul 15, 2022
Here's a list of what you will see on an AstroTour this summer! M44 - Beehive Cluster [in cancer] (back up open clusters: M39[Cyg], M11[Sco], M6[sco], M21[Sag], Double Cluster [Per])
Open cluster
Can be seen as a mist, cloud, or fog with the naked eye. Kinda like a little drip of the milky way that strayed.
“Town of stars, just down the road” aka: Thousands of stars, hundreds of light years away (actual distance 520 to 610 ly, and about 1,000 stars).
like little towns of stars just down the road like Lyons, Jamestown, or Nederland. Hundreds of light years sounds far and it is a mind boggling large distance but compared to the globular clusters and galaxies (thousands and millions of light years away respectfully) we look at, it is just down the road.
What does it look like to you? I hear some say an arrow head, some say, bees, butterflies, etc. some just say “stars”
Try to count/estimate how many stars you see it should be at least ~70 so this might take a while
Open Clusters are like teenage stars. They were likely all fourmed closer together, in the same star forming nebula (or more simply “stellar nursery”), and are now spreading out leaving the nursery and going their own ways in our galaxy
Cloud of stars in our galaxy ~39 light years wide with a core that’s about 11 ly wide
Total mass is about 550 times that of our sun
Age of the cluster is about 650 million years old
I think of this like young or *teenage* stars. Stars get to be billions of years old, our sun is 4.6 billion years old
One of the first objects Galileo studied in a telescope. First called “little mist” by a greek poet in 260 BC
The main thing to see in the constellation Cancer
Seen as a manger and the two stars next to it seen as donkeys eating from the manger by the Greeks and Romans
In China it was seen as a ghost riding a chariot and is one of the 28 chinese zodiac signs (lunar mansions)
Origin of calling it the “beehive” is unknown.
M13 - Hercules Cluster [in Hercules] (back up globular clusters: M4 [Sco], M5 [Ser], M22 [Sag], M3 [CVen], M92 [Her])
Globular cluster
“city of stars” Thousands of light years away, Millions of stars (actual distance 23 thousand ly away, about a million stars) like far away a mega city of stars like NY, LA, Madrid, Tokyo. thousands of light years away is far compared to the open clusters we look at but it’s still in our galaxy and really close compared to the galaxies we look at.
We’re seeing how it looked 23 thousand years ago because it’s 23 thousand light years away but little has probably changed as these clusters are ancient.
M13 is twice the age of our solar system at 11.6 billion years old
M13 is about 84 light years across and if our solar system was in it we would have about 500 times more stars in our sky as it’s so dense with stars
Can’t count all the stars, many stars can be seen on the edge of it but as you get closer to the center core it becomes a fuzzy glob of star light from millions of stars shining together.
What does it look like to you? I usually get spider webs, or shards of glass. Sometimes I hear spilled salt or sugar. My favorite is a girl scout who said it looked like a dandelion seed ball just before you blow it out. My least favorite is a nurse who told me it looks like COVID in a microscope.
On really dark moonless nights you can just barely make it out with the naked eye as a faint fuzzy star if you have really good eyes
Easily found in binoculars, first look for the “keystone” of hercules (Vega in the summer triangle points at the key stone) Then it’s about halfway in between the western most two stars of the keystone (see chart on other side).
Discovered in 1715
Brightest and richest of all of the globular clusters in the northern hemisphere. (omega centauri, and 47 Tuc are only two that are brighter but they can only be seen in the southern hemisphere)
We usually show at least two globular clusters to show how different the globular clusters can look. I think M13 looks more like an american city (like dallas/ft.worth) with sprawling suburbs, where M92, and some of the others, look more like a european city with a dense urban core (like Madrid or Tokyo).
In 1974 we sent a high powered radio signal called the arecibo message (named after the now defunct arecibo observatory that sent it) to M13 potentially telling any life in M13 about life on earth. It will still take over 23 thousand years for the message to reach M13 and another 23 thousand years for a response (if any) to come back
Globular cluster’s origin is a mystery, usually said to be old cores of galaxies that our galaxy has run into and consumed/captured. This has been called into question as there’s a nebula (the tarantula nebula) in a satellite galaxy of ours (the large magellanic cloud, unfortunately only seen in the southern hemisphere) that seems to be forming a globular cluster. The mystery being that all globular clusters we see (even in other galaxies) are made up of super old stars, except for one; right on our doorstep we see what looks like it’s one being born. So if you can think of a story for why that would be, I would love to hear it and I would love even more to be cited on your paper when you write it ;)
M81 - Bode’s “Nebula” {galaxy} [in the big dipper (UMa)] (back up galaxies: M82 (whirlpool) [UMa], M51 (sunflower) [CVn], M104 [vir], M64 [com], M63 [CVn], M87 [vir], M86 [vir], M66 [leo]
Galaxy
Billions of stars, Millions of years away
Looks like a faint fuzzy thing, can no longer see individual stars (too many stars too far away) but only see millions of stars shining together in a luminous cloud.
12 million lightyears away, the light (photons) you’re seeing left that galaxy 12 million years ago and has been traveling all the way through space for 12 million years to land in your telescope and interact with your retina so you are having a physical interaction with a galaxy 12 million light years away… not bad for a “faint fuzzy” thing
70,000 light years across
The furthest away we will look in the telescopes much farther than the globular or open clusters
Everything we look at tonight exists a multitude of times in this other galaxy. This galaxy has about 250 billion stars, each of those stars just like our sun likely has many planets, and many of those planets have multiple moons, it has thousands of nebulae, thousands of open clusters, and hundreds of globular clusters.
It’s called bode’s “nebula” because before the 1920s we didn’t even know other galaxies were out there and everything astronomers saw that were faint and fuzzy in a telescope were called “nebula”. It wasn’t until Edwin Hubble using the biggest telescope at the time looked at this galaxy and about a dozen others and realized that they were other galaxies. It wasn’t until the 1930s that other galaxies became widely accepted as astronomers had thought our galaxy to be the entire universe at the time, and Hubble was saying our galaxy was just one of many. Now NASA has cataloged over two trillion galaxies (that’s just what they’ve counted, we know there’s more), so less than 100 years ago astronomers thought the universe was half a trillionth of what we know it to be today. Makes you wonder what the next 100 years holds for us
There is a black hole in the middle of M81 that is 70 million times the mass of our sun
If there’s extra time we show M82 as well it’s right next to it and shows how different the galaxies can look if you’re looking edge on (M82) or more of a top view of the full disk (M81)
M81 and M82 collided a few hundred million years ago causing M82 to be deformed.
M81 is 150,000 light years away from M82 right now
M81 and M82 are still interacting gravitationally this has pulled some gasses from M81 to M82 letting M82 form more stars
In zoomed out binoculars you can get M82 and M81 in the same field of view.
Can’t be seen with the unaided eye but easily seen in decent binoculars
Can be found by using the diagonal stars of the vessel of the big dipper as a pointer (see chart)
Discovered in 1774
It’s slightly bigger than our own galaxy.
M57 - Ring Nebula [in Lyra] (back up planetary nebula: M27 [Vul], NGC 7293 (helux) [Aqr], NGC 7009 (saturn) [Aqr], NGC 6543 (cats eye) [Dra], NGC 2392 (eskmo) [Gem], NGC 3242 (ghost of jup) [Hyd])
The “ring nebula” is a planetary nebula
Looks like a little cheero ring or little poof ball
It’s actually about 1,000 times the size of our entire solar system
Sometimes you can see a little white dwarf star left behind in the middle this “dwarf” star is actually about the size of earth
Planetary nebulae are called “planetary” by mistake, early astronomers thought the little disk looked like a planet in a telescope.
The ring nebula is only seen in telescopes (you won’t see it with just your eye and won’t see it even in fairly good binoculars)
You might be able to notice the ring isn’t perfectly round but slightly elliptical in the telescope
It’s roughly 2,000 light years away but it’s hard to really tell how far it is
It’s about 7,000 years old
Usually seen as white but some eyes see it as greenish
“A ghost of a star”, planetary nebulae are stellar ghosts. They are old exploded star remnants
It was a sun like star that blew away the outer envelope leaving behind the earth size white dwarf
Stars are a very complex topic in astro physics, there’s a whole separate part of physics called heliophysics that’s the study of stars. You can get a PHD in heliophysics and still not know everything about stars. So this is an oversimplification and don’t worry if you don’t get it:
Stars are really really big
Our star the sun is 112 times the diameter of earth, if you square that to get the volume it’s over 1 million times the volume of earth
The gravity on the sun is also about 1 million times that on earth
If you were on the sun you would weigh 1 million times what you do now and collapse under your own weight
Because of the immense gravity everything on the star is collapsing to the center pushing really really hard on the center. It pushes so hard that the nucleus of the atoms in the center core of the star are being pushed to touch each other this is called “fusion”
Fusion causes a huge explosion (the only time we’ve ever done fusion on earth was the hydrogen bomb) this explosion starts pushing aginst the immence gravity of the sun and balances the star out creating the consistent light we’re used to from our sun.
This balance lasts billions of years but eventually all of the hydrogen in the star is fused up. Hydrogen is the easiest to fuse (that’s why we did it in the ‘hydrogen’ bomb) once it’s gone the gravity starts winning and pushing harder on the core.
This increase of gravitational pressure pushes bigger and bigger elements together in fusion at the core (until Iron which will not fuse). Fusing these bigger and bigger elements means the explosion in the core of the star can go bigger and bigger, eventually it blows apart the star, pushing all the stuff that made up the star’s outer layer away in all directions in a ball of gas, leaving behind the core as an earth sized white dwarf star in the center.
That is what you’re seeing in the planetary nebula an old exploded star (if the star was bigger it could have formed a black hole… but that’s probably too deep of a theoretical physics conversation than you want to read right now)
Antares - Fake mars (back up any bright stars low on the horizon : Archturus, Vega)
Red giant star in Scorpio
The name Antares is Arabic and means mars’s rival
Both Antares and mars are bright red and both are on “the ecliptic” (the only part of our sky you can see planets) causing it to be mistaken for mars often.
The rivalry comes from Mars only being brighter than Antares one out of three years.
If we shrunk down our solar system so that the earth was 1mm big (about the size of a grain of sand), the sun at this scale would be 112mm (about the size of a grapefruit) and 10 meters (about 10 yards) away from our 1mm earth. At this scale Mars would be about a .7mm grain of sand and would be about 17 meters (~17 yards) from our 112mm sun.
Because Mars orbits the sun from further away than the Earth it takes Mars about 2 years to go around the sun (it of course takes the earth only one year to go around the sun). So that means once every three years we catch up with mars and pass it on the inside lane. So one year out of three we are on the same side of the sun as mars.
So going back to our scale one year out of three we are (17m-10m=) 7 meters (~7 yards) away from Mars, but two out of three years we are on the opposite side of the sun from mars (17m+10m=) 27 meters (~27 yards) away from Mars.
Antares being a far away star doesn't change brightness but getting closer and further from mars means mars brightness fluctuates a lot.
When we are on the same side of the sun as Mars, Mars is brighter than Antares but when we are on the opposite side of the sun from mars Antares wins the rivalry.
Antares is huge!!!
If the sun was replaced with Antares the earth’s orbit would be well inside the star, even mars would be in Antares if we swapped it for the sun as the width of antares is a bit bigger than mars’s orbit.
Antares is actually the biggest physical object you can see with the unaided eye.
If the sun was the size of a grape antares would be the size of a small car
Antares is the heart of the scorpion scorpio. You can see the red beating heart of antares on the horizon, above it and slightly to the right you can see a line of three stars that represents the head and two claws of the scorpion. Later in the summer you will see the tail and stinger rise above the horizon.
Scorpio is actually Orion’s rival. The Greek story is Scorpio killed Orion so when they put them in the sky they put Orion and Scorpio on opposite sides of the heavens. Because they are on opposite sides you can never see Orion and Scorpio together in the sky. It’s kinda like they have a restraining order.
Antares appears to twinkle or beat because of the atmosphere. If you imagine the air above us like a blanket, if you look directly up you’re just looking through the thinnest part of the blanket but as you look towards the horizon you’re looking through the length of the blanket. Because Antares is lower on our horizon you’re seeing it through more atmosphere which makes it twinkle more. Kind of like how when you watch the sunset over the ocean you can sometimes look at the sun’s last glint of light because the light is going thru so much of the earth’s dirty atmosphere it’s acting like sunglasses blocking most of the light
Antares has a faint nebula around it only visible in the biggest of telescopes and the best eyed observers
It’s truly red and can be seen as red even to the unaided eye
It’s 600 light years away
Mizar or Algieba -double star (Algieba for June to early July, Mizar for July on)
Without looking at the chart (no cheating) can you tell which star of the seven in the Big Dipper are actually two stars?
This was used as an eye exam in the Roman military. If you could pick out the star in the Big Dipper that was actually two stars with the naked eye you could pass the eye exam
This was also seen as a double star in ancient India and represents a married couple in hinduism.
..... Do you have a guess? Check again just to be sure.... You can only really take this eye exam once
ok hint it's in the handle.... sure of your guess now...
Okay, If you picked the middle star of the handle (labeled as Mizar on the chart), great news you have good eyes!
Once this is pointed out most people will see it as two stars
Looking even closer In a telescope you might be able to see one of these stars are two stars also!
It’s actually very common for stars to have companion stars, about 60% of stars have companion stars. Our Sun is actually in the minority for being alone.
It's like when you drive a desert highway at night you might see one oncoming headlight on the horizon but as you get closer you'll see it split into the two headlights. The telescope is getting you close enough to see it as two stars.
Algieba
The one in leo is another eye exam this one is a lot harder (I can see the one in the big dipper but I have trouble seeing the one in Leo)
I usually have people start with the big dipper one then the ones that get it I give them the one in Leo
..... Do you have a guess? Check again just to be sure....
ok hint it's in the mane.... sure of your guess now…
Okay, If you guess the brightest one in the mane you have really good eyes!
Moon (when up) Earth’s only natural satellite
Moves around the earth in just under one month. The word month actually comes from moon-th, the suffix -th denotes a measurement like 1/4th or 100th place, one ‘measurement’ of the moon means from phase to phase of the moon. The Month is actually a time period we inherited from a lunar calendar and aligns with the moon as good as you can hope for with our solar calendar.
The moon rises/ sets just under an hour different every day (~50min). So if you see the moon set tonight at 10pm it’ll set just before 11pm (~10:50p) tomorrow. Or if you see the moon rise at 5am tonight you will see it rise just before 6am (~5:50a) tomorrow
The moon is about 250,000 miles (400,000 km) away (I think of this as how many miles some old cars will have on them.
The moon is 2,000 miles across, just under the distance from coast to coast of the US
If we shrink the earth to be 1mm (the size of a grain of sand) the moon would be ¼ the size of earth at .25mm and would be about 30mm (or 1.25 inches) away so, two grains of sand in the palm of your hand would represent the earth and moon at this scale. Feel free to play around with this scale to what works best for you as long as you change all units it will work i.e. if the earth was 1ft (the size of a watermelon) the moon would be (1ft/4 =.25ft = 3in) 3 inches (the size of a baseball) and it would be (1ft *30 = 30ft = 10 yards) 10 yards away.
Monday is named after the moon like Moon-Day. Same in spanish; Lunes = monday, luna = moon. Same in french.
The moon is of course responsible for tides causing “king” tides (big tides) when full or new, And “neap” tides (small tides) at first and last quarter.
The moon is responsible for life as we know it on earth. It’s theorized life may not of evolved to leave the ocean if it weren't for the irregular tides the moon gives us
Werewolves might not exist but because wolves and coyotes are nocturnal hunters the full moon nights provide better visibility and means they are more active so you might actually hear someone howl at the moon.
The moon is best seen in phases as the shadowing causes the features such as craters to pop out more giving the viewer a better sense of depth. When studying a feature on the moon astronomers will wait all month until the feature they want to study is perfectly shadowed.
The half illuminated moon only gives 11% of the light of a fully illuminated moon because the craters make the moon more like a rough golf all than a smooth ping pong ball the light isn’t reflected uniformly.
The Moon is 400,000 times dimmer than the Sun
The moon only reflects 7% to 17% of the Sunlight that hits it (depending on the dark vs bright areas) so it would be dark gray to black if it weren’t for the contrast of the black background of space
Because the moon gets its light from reflecting sunlight you will see the side pointing towards the sun to be always illuminated. That is the western side during the evening and the eastern side at times when it's only up in the morning.
The closer the moon is to the sun the smaller the crescent the moon will make
Full moons are on the exact opposite side of the sky from the sun
Many astronomers hate on the moon because the natural light pollution of the moon drowns out all of the fainter features in the night sky. However I think anything the moon takes away from the sky it gives back tenfold as it’s one of the best things to see in a telescope you can’t see the carters or little features on anything else in the sky. The features of the moon spark wonder and show you it’s an actual place.
The Moon is the only thing bright enough you can take a picture of it through the telescope with any camera phone.
The Moon-Earth system is very rare we don’t see planets this close to their star with a moon this size in any other star systems we’ve seen
The moon broke off from the earth during a big collision in the early solar system.
The man/rabbit/whatever on the moon is like a cultural rorschach test, what do you see?
The marea (low dark regions) are about 3.7 billion years old meaning most the craters happened before the marea were formed and are mostly preserved on the highlands area of the moon
You can watch the moon go thru all the signs in the zodac over the course of a month
Watch the moon over the course of a week if you start when the moon in near regulus (the heart of leo the lion) the next night you will see the moon near the tail of leo the lion, the night after that it will be closer to Spica in Virgo, it’ll spend 2 or 3 days in virgo then visit zubenelgenubi/zubeneschamali (the balance beams of Libra), then it will visit Scorpio for a day or two, then on to Sagittarius, and so on…
If you watch the moon over the course of a day you might think it’s going from east to west but, if you watch it over the course of a week you will see its true rotation is from west to east. This is like watching out the side window while your mom passes a car. At first it might look like the car you are passing is going backwards but after watching for a while you will see it’s going the same direction just slower than you. Take note of where the moon is today vs tomorrow.
Lagoon nebula (M8) / Swan nebula (M17) (late June)
These are star forming nebula
They don’t look as red or colorful as they do in pictures, (often depicted on yoga pants, phone cases, etc.) because our eyes are bad at seeing color at low light levels. Many photos also cheat by showing things in the infrared and ultraviolet (reds and purples that are outside what's visible to the human eye) and paint them on as reds and purples like you can see it. This is helpful scientifically and makes for a good pic but won’t be what you see in a telescope.
However, The eye can see deeper into the nebula than a camera can easily as you can peer through the gas and see the stars inside the nebula. Where pictures look flat and washed out in the telescope you will get a 3D feel for the nebula that can only be seen with the human eye.
In the telescope it will look like stars mixed with alluring milky regions and enticing dark regions.
There are three types of nebulae visible in these
Emission nebula - clouds of gas so hot they illuminate themselves with light. Similar to the gas that illuminates a neon light
Reflection nebula - a cloud of gas that is near a star that is lighting it up. Like how the spotlight from the bat signal lights up the clouds over gotham
Absorption nebula - a dark cold cloud that blocks the light shining behind it. Like how the clouds in our sky block out the light of the stars behind them
These nebulae are like a stellar nursery. Stars travel through these clouds taking in more and more gas until they’re big enough to start fusion in the core of the star they then ignite and that’s how a star is born. These are baby stars sending their first light out into our universe.
Distance: lagoon = 4,100 light years, swan = 5,500 ly
Size lagoon = 55 × 20 ly, swan = 11 x 11 ly
About 800 stars will be formed from the contents of the swan and even more for the lagoon
They both fall inside the milky way in our sky
