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Giant Hydrogen Bubbles in the Milky Way

 

Dear Friend of Lookout Observatory,

The arms of spiral galaxies like the Milky Way tend to be filled with many young, hot blue stars and giant hydrogen gas bubbles or nebulae. Hydrogen, the simplest and most abundant element in the universe, consists of a single proton with a single electron. Hot blue stars emitting high energy ultraviolet light in the midst of clouds of hydrogen strip away the electrons, leaving ionized hydrogen (single protons without the accompanying electron) and causing them to radiate a single wavelength of red light (called H-alpha). Large nebulae of ionized hydrogen gas are known as HII (pronounced H-two) regions, and they are common in the arms of spiral galaxies. Today’s pictures are of a group of large nebulae of ionized hydrogen in our own galaxy, glowing with the red light of H-alpha.

The first picture shows a large area of the winter sky, with Orion at the lower left, the constellation Taurus in the center (with it’s brightest star, the red giant Aldebaran in the center of the picture, the Pleiades cluster above and to the right, and the southern part of the constellation Auriga in the upper left corner. Green lines are added to help you follow the brighter stars that make up the constellation star patterns. The bright blue rectangle outlines the 5½° x 7° area of Auriga that is shown in the next picture.

Most of the second picture is filled by a huge hydrogen bubble known as Sh2-230, but despite this being an almost 4 and ½ hour time-exposure, much of this cloud is invisible or very faint. The faint reddish-gray swirls, splotches and streaks (as distinguished from the slightly darker bluish-gray background) are all part of this giant hydrogen bubble about 900 light years in diameter. Brighter, denser parts of this hydrogen nebula are given separate names – the Spider Nebula and the Tadpole Nebula, for example. The largest bright nebula (at the right), named the Flaming Star Nebula, is not part of the giant Sh2-230 nebula. It is only about 1/7 the distance to Sh2-230, and it looks so large and bright because it is so close. Most of the other red hydrogen nebulae in this photo are star-forming regions and have recently formed clusters of stars embedded in them. In addition, in this picture are 3 identified open star clusters (M36, M38 and NGC 1907), each with a few dozen to a few hundred stars, and all lie in front of Sh2-230, being less that half as far away from us.

Close up photos of the Tadpole Nebula and the Flaming star Nebula are the third and fourth pictures, and those of you who enjoy the pictures but tire of technical details should just look at them and ignore the very wordy explanations that I’m going to continue with for those with deep astronomical interest. All except the first picture of the winter sky were taken through a narrowband filter (to screen out heavy light pollution), so red color is emphasized and the colors aren’t quite true. Nevertheless, please enjoy the cosmic beauty!

Click on any image to get a closer look

E77 Winter sky 1mx25-lines
The Winter Sky
B5-6Comb Sh2-230 Nebula - over 4 hrs
A huge hydrogen bubble known as Sh2-230
C44-45Comb IC410 - almost 5 hrs
The Tadpole Nebula
C46 IC405 -almost 3 hrs
The Flaming Star Nebula

For Hard Core Folks

Let me start with a note about naming and then go through more detail about objects in the second picture. Stewart Sharpless, an astronomer with the US Naval Observatory, in 1959 published his second catalog of 313 nebulae, mostly ionized hydrogen (HII) regions. So Sh2-230 is number 230 in his second catalog. Many of the brighter nebulae in his catalog have multiple names because they were already listed in other, earlier catalogs. Charles Messier in the eighteenth century published several editions of a catalog of fuzzy objects, so the brighter deep sky objects (star clusters, nebulae and galaxies) are identified as M with a number from his catalog after it. The New General Catalog of Nebulae and Clusters of Stars ( abbreviated NGC) listing almost 8000 such objects was published in 1888, and by two decades later more than 5000 additional objects were given numbers in supplemental Index Catalogs (abbreviated IC). So for example, the Tadpole Nebula is known as IC410, but also as Sh2-236.

All the objects in the second picture are in the winter Milky Way, that part of our galaxy looking away from the center. Below is a drawn map of our Milky Way galaxy as seen (imagined) from above, looking down onto the plane of our spiral arms. The location of the Sun, about halfway from the center to the edge, is shown by the bight red dot. This map was made in 2008 by Robert Hurt, an astronomer at the Spitzer Science Center, and revisions are being proposed as more information is learned.

Milky Way Map by Robert Hurt v2

Note that the center of our galaxy instead of being round is stretched out into a bar, and the spiral arms start from the ends of that bar. This is known as a barred spiral galaxy. The earth revolves around the sun in approximately the same plane as the plane of the galaxy. In the (northern hemisphere) summer the earth is closer to the center of the galaxy than the sun is, so at night when we see the summer Milky Way, we are looking toward the center (looking down on the map). In the winter the earth is on the opposite side of the sun, farther away from the galaxy center, and when we look out at night, we are looking up on the map, away from the center. The winter Milky Way looks dimmer in the sky because we are looking at only about ¼ of our galaxy rather than in the summer when we are looking at ¾ of it, including the densest center part. Many of the objects that I photographed this winter in the second picture, including the giant nebula Sh2-230, are about 10,000 light years away from us in the Perseus arm of our galaxy. (Note the concentric circles on the map going out from the sun’s position are 5000 light years apart, so going up anywhere from about 6,000 to 10,000 light years from the sun on the map puts us in the Perseus arm.)

Starting at the left in the second picture, we have the small, bright red splash of Sh2-235. It and the tiny red circle named Sh2-233 just to the right of it plus several other HII regions not shown here are all part another huge hydrogen cloud – separate from Sh2-230 — in the Perseus arm. New stars are forming in these HII regions. Moving further to the right we come to a small red spot labeled Sh2-237 (also known as NGC 1931 and the Fly Nebula because it is small and close to the Spider Nebula). Small is relative; it is over 10 light years in diameter! This and the neighboring Spider Nebula both have young star clusters recently born out of the condensed hydrogen gas. The Tadpole Nebula, like the Spider and the Fly, is a more concentrated region of the vast Sh2-230 hydrogen bubble. The star cluster embedded in its center (with it’s own name of NGC 1893) contains about 4600 stars born there about 4 million years ago, very young in cosmic time.

If you look at the third picture, which was taken with a larger telescope than the second picture, you will see a larger, more detailed view of the Tadpole Nebula. Just above and slightly left of the central star cluster are two little red tadpoles of denser gas facing the cluster. This is how the nebula got its name. Their shape is being sculpted by the stellar winds (radiation pressure and particles) from the hot blue cluster stars. These two “little” guys are each about 10 light years long. The bluish cast to parts of the nebula is caused by blue light from the cluster stars being reflected off of dust particles, which are commonly scattered throughout such HII nebulae.

And finally, the fourth picture is of the Flaming Star Nebula taken with a larger telescope. As I mentioned before, this nebula is much closer than the Perseus arm, only about 1500 light years distant, so it is in the same arm as the sun, the Orion Spur. On the map it would be only a little bit outside of the red dot, since the dot itself is has a radius of about 1000 light years. Unlike the other nebulae that have embedded clusters of high energy stars that are causing the gas to glow, this hydrogen nebula is energized by strong ultraviolet radiation from the single brightest star in the nebula (a bit above the center of the picture). It goes by the name AE Aurigae. This star was not born here, but rather is an interloper, having been ejected a few million years ago from the Orion Nebula region, and is now only passing through this cloud of hydrogen, causing it to temporarily glow brightly. And this ends our tour of the sky in a small region of the constellation Auriga.

Infomation came from various online resources, mostly Wikipedia, NASA, and especially Kevin Jardine’s Galaxy Map at galaxymap.org.

Keep looking up,

Carter, (sometime) Resident Astronomer

Lookout Observatory

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A Warm Heart to get you through the Winter

 

Dear Lookout Observer,

Due to the frequent smoky California skies in the summer, ongoing concerns about the coronavirus, a lot of cloudy weather, and various family obligations, I have been unable to get to Lookout Observatory much this year. As a result I have had to resort to using the Observatory’s Southern Outpost (otherwise known as our backyard in Albany, CA) to get some pictures to send to you. The problem is that this Outpost is surrounded by major light pollution, which makes it impossible to see any but the brightest stars in the sky. Fortunately, modern science has developed a reasonably good solution – narrow-band filters. These filter out most light pollution and let only a few narrow wavelengths of light through, especially those wavelengths that are emitted by most galactic nebulae.

Image 1: If you live in a mid-northern latitude where there are dark, non-light-polluted skies, and you went out now on a clear night at about 9 PM, and you faced south and then looked up straight overhead, you would see a sky something like this image, except everything would be fainter (because this is a 25-minute time exposure, and your eyes can’t accumulate light over that much time). [This image was taken at Lookout Observatory.] Of course you wouldn’t see the green lines which I have added to make the constellations easier to find. But if you tilted your head back even further so you were looking a bit north of overhead, you could see the W-shaped constellation Cassiopeia (near the middle of this photo). Its 5 main stars that form the W are bright enough to be seen even in Albany with a lot of Bay Area light pollution. And just left of the W is a rectangular piece of sky marked with blue lines. This outlines the next picture.

Image 2: This approximately 5° x 7° piece of the sky contains two bright nebulae consisting mostly of glowing hydrogen gas, and each has one or more clusters of stars associated with it. Popularly known as the Heart and Soul Nebulae, each are regions of ongoing star formation. Previous generations of stars have exploded, spewing dust and gas into the region. Radiation and winds from current massive, hot stars cause the gasses to glow, and they create large cavities in the gas and dust, pushing outer regions together enough so that they begin condensing to form new generations of stars. The Soul Nebula on the left looks more like a fetus to me, but maybe that’s what souls look like? It is about 6, 500 light years away. The Heart Nebula is about 1000 light years beyond that. This picture is an hour and 40 minute exposure taken through a 200mm telephoto lens in our back yard.

Image 3: I rotated this close-up image so it looks more like a traditional heart shape. It is a seven-and-a- half-hour exposure taken through a telescope of 650mm focal length in our back yard. This heart of gas and dust is over 8 light years or about 50 trillion miles across. The hydrogen gas glows red when energized by the hot blue stars in the embedded cluster, and their blue light is scattered and reflected by the interspersed dust, the dark opaque parts of which have been carved into long columns and odd shapes by the intense radiation pressure from the existing stars.

I hope this heart brightens your long, dark winter nights, and I wish you Happy Holidays!

Keep looking up,

Carter, Resident Astronomer (rarely) of Lookout Observatory

Click on any image to get a closer look

E76 Winter sky near Cassiopeia 1mx25-lines
Winter sky looking south
B4 H+S IP5mx20DDBrCon4HSLSmoo-Crop2
Heart & Soul Nebulae
C40-42 Heart Nebula - 7 and a half hours from backyard
The Heart Nebula

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A Lookout Observatory Bulletin: Our Galactic Neighbors

Dear Lookout Observers,

On the eve of American Independence Day, traditionally celebrated by a display of fireworks, I am sending you a picture of celestial fireworks of tremendous magnitude. It is an object known as M1 or the Crab Nebula. For regular recipients of this bulletin, you may remember that I sent out a picture of this object just about a year and a half ago, taken from my back yard in Albany, CA. Because of serious Bay Area light pollution, I used a filter designed to reduce the effects of that pollution. But I have taken a more recent picture using a narrow-band filter that further enhances the beautiful H-alpha light of the many filaments of glowing gas of ionized hydrogen, and I combined it with the earlier image to give a backyard picture that was accumulated over 2 hours and 43 minutes of time and shows more nebulosity than the earlier picture did. This is the first image below.

If you didn’t see the earlier writeup, I’ll just state again that M1 is a supernova remnant, meaning it is the gaseous shell of a star that blew its outer part away, leaving only a super dense neutron star core at the center. The explosion that started the gases expanding occurred almost 1000 years ago, and it was of course many trillions of times greater than the explosion caused by a very loud M80 firecracker. Since all fireworks are illegal in California, and even where they are legal, they can be really annoying to your neighbors, why not just enjoy looking at M1 this 4th of July instead of listening to an M80? It is a peaceful way to celebrate American Independence Day.

But an image of M1 has another use besides being a very silent explosion. These days the coronavirus has caused a worldwide pandemic already causing more than half a million deaths worldwide, and it has disrupted the world economy and caused tremendous financial hardship to untold millions. Even to those who have escaped the worst of its medical consequences, it is causing a great deal of mental stress, fear and anxiety. Psychologists sometimes use a technique called visualization to help reduce stress, and I hope you might find this helpful in calming the stress from the coronavirus. One type of visualization technique uses your imagination to turn a negative or feared object or situation into a positive or pleasant object or situation. It just so happens that the feared coronavirus can be easily turned into the beautiful M1 (or Crab Nebula).

The next 6 pictures will help you do this. First look at the microscopic view of the feared coronavirus. In the next picture we squash it down, making it oblong and releasing some of our anger at it. Then you look at each successive picture, and you see it magically change into the beautiful Crab Nebula. After this visual aid, you can now close your eyes any time you wish and picture the virus turning into a quiet, harmless cloud of expanding gas 11 light years across and 6500 light years away. As you do this, allow peace to descend into your body. Do this several times a day, and it will improve your sense of well-being. Refer back to these transforming pictures as needed to reinforce your ability to create the imagery in your mind.

If this doesn’t work for you, it is simply proof that Anitra was right. She says this whole idea is the product of a coronavirus-locked-down seriously disturbed brain gone to mush. Well, it is the thought that counts: I hope each of you gets through this pandemic safely, peacefully, with your sanity intact.

Keep looking up,

Carter, (sometime) Resident Astronomer,

Lookout Observatory.

 

Click on any image to get a closer look

RC4&10 M1 -final10crop
The Crab Nebula
Coronavirus1
The Coronavirus
Coronavirus-to-M1-2
Coronavirus evolves into Crab Nebula 1
Coronavirus-to-M1-3
Coronavirus evolves into Crab Nebula 2
Coronavirus-to-M1-4
Coronavirus evolves into Crab Nebula 3
Coronavirus-to-M1-5
Coronavirus evolves into Crab Nebula 4
Coronavirus-to-M1-6
Coronavirus evolves into Crab Nebula 5

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More Animals from Lookout Observatory

 

Dear Lookout Observer,

With much of the world staying at home and keeping a distance from others due to the coronavirus pandemic, it seems we can all use a diversion from our immediate stressors. So to get away from worldly cares, please let me take you up to 30 million light years away. In our last report we looked at 3 animals in the sky. This time it’s a challenge: can you match 6 more animal pictures with each object’s description?

Some of these might be easy because you may have seen them before, especially if you are a long time recipient of these reports. But some might be difficult because astronomers, both ancient and modern, have always had to stretch their imaginations to find meaningful shapes in random sprinkles of stars (called constellations) or fuzzy patches of light in a telescope (nebulae and galaxies). So you might be hard pressed to see the named animal in some of these pictures. But if you can’t figure it out, just ask a friendly 4 to 8 year old. They are usually much better at seeing animals in clouds – or celestial wonders – than adults are.

Happy matching, Carter, Your Lookout Astronomer

A. Eagle First up is the Eagle Nebula located in the constellation of Serpens Cauda (the serpent’s tail). It is a huge emission nebula (dozens of light years across) of glowing gas and dust with an embedded cluster of thousands of stars. A small part of the nebula which is a region of active star formation was made famous as a Hubble telescope image. The full extent of this nebula covers an area of sky about the size of the full moon. It is a typical emission nebula consisting mostly of hydrogen gas energized to glow red from the energy of embedded stars, and containing dark areas where dust obscures the glowing gas.

B.Swan The Swan Nebula is another huge (15 light years across) emission nebula in the constellation Serpens Cauda. It also has a large cluster of embedded stars, with many more in the process of forming. It occupies an area of the sky about ½ the diameter of the full moon

C. Owl The Owl Nebula is a so-called planetary nebula. This kind of nebula got the name ‘planetary’ because in early telescopes they resembled the appearance of planets, being circular, appearing larger than stars, and being fairly evenly illuminated. Like many planetary nebulae, the Owl is a couple of light years across, and it is caused to glow by a central star. A planetary nebula is typically created when a star no more than 8 times the mass of the sun reaches a later stage of its life when its outer layers are driven away from the core to form an expanding sphere of gas, and the remaining star is condensed into an extremely dense white dwarf star. The Owl Nebula is located in the constellation Ursa Major, the brightest stars of which form the Big Dipper. Most planetary nebulae appear quite small. The Owl, even though it is one of the largest appearing ones, looks only about 1/9 the diameter of the full moon. It got its name because it looks like the head of an owl, not the whole bird.

D.Pelican By Now you may be thinking this game is for the birds, but I promise soon we will branch out to other animals. The Pelican Nebula is yet another vast emission nebula glowing with the characteristic red of excited hydrogen atoms. It is located in the constellation Cygnus the swan, and new stars are forming out of eddies of this hydrogen gas. Because it is about three times closer than the other emission nebulae in this group, it appears larger in the sky, covering an area about 2 times the diameter of the full moon.

E. Jellyfish The Jellyfish Nebula is a supernova remnant located in the constellation of Gemini, the twins. A supernova results from the later stages of evolution of a star many times more massive than the sun. When a massive star runs out of thermonuclear fuel, it implodes, forming a dense stellar core called a neutron star. The outer layers of the star collapse toward the neutron star, then bounce outward in a supernova explosion. If a neutron star is spinning rapidly, it produces a beam of radiation, and it is called a pulsar. The radiation sweeps by like a beacon of light from a lighthouse and can be detected as pulses of radio waves and other types of radiation. This particular supernova, which blew up thousands of years ago, is driven by an embedded pulsar, and lies within a giant molecular cloud with varying densities, so its interaction with the cloud material has caused much distortion from the typical more spherical shape of early supernova ejected material. Currently this nebula is about 70 light years across, and the shock wave is expanding at about 20 to 60 miles per second, depending on the density of the material it is passing through. At its distance of about 5000 light years, it occupies an area of sky about 3 times the area of the full moon.

E. Whale Up until now all the objects discussed are within our Milky Way galaxy, from about 2 to 7 thousand light years distant. But for this object we go 30 million light years out in the direction of the constellation Canes Venatici, the hunting dogs. The Whale Galaxy is a spiral galaxy seen edge-on, which appears in the sky to have a length about ½ the diameter of the full moon It is actually about the size of our own galaxy, and looks a lot like our galaxy would look if seen edge-on from that distance. The center of this galaxy is full of star formation and multi-element-rich gases from many previous supernova explosions. There is a small ‘dwarf’ galaxy next to it, which some see as a pup swimming next to its mother whale in the vast astronomical sea.

Click on any image to get a closer look

1-SC10
The Eagle Nebula
2-E62
The Swan Nebula
3-L228
The Owl nebula
4-S132
The Pelican Nebula
5-S238
The Jellyfish Nebula
6-S175
The Whale Galaxy

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Animals in the Sky

 

Dear Lookout Observers,

I hope each one of you is safe and keeping your distance from others, since even people who are not sick may be unknowingly spreading the coronavirus. If you are like me, you are spending most of your time during this pandemic holed up in your home and sometimes going a bit stir crazy. What better time to escape into outer space? And if your brain is feeling a bit mushy like mine is, you don’t want a bunch of technical stuff straining it right now. So how about some animals? Everybody like animals, right?

The first picture is one you have probably seen before. It is probably the most famous dark nebula in the sky – the Horsehead Nebula. It is located in the constellation Orion, and it really looks like a horse’s head poking out of that dark cloud.

To find the next animal we start with the next picture, a view of the dark sky from Lookout Observatory in the fall at about 9 PM, looking straight up. Overhead we see the magnificient Milky Way. The triangular shaped pinkish nebula somewhat to the right of the center of the diagonal line of the Milky Way is the North American Nebula. But if you look closely just above the center of this streak of Milky Way, you will see a darker reddish spot about the same size as the brighter, pink North American nebula. It is hard to see.

I try to help orient you in the next picture by drawing in lines of the constellations in green and I show the reddish spot I’m talking about in the center, outlined in blue. If you were facing south and looking straight up, and then you arched your back so you were looking behind you, you would see the north star and the little dipper, which is at the top of this picture. The north star is the bright one at the end of the handle. If you look to the left side, you see a sideways “W.” That’s the constellation Cassiopeia. And just to the right of it is something that looks like a house with an irregular bottom, or maybe a blank face with a pointed wizard hat on top. That’s the constellation Cepheus, and that’s where that little blue rectangle is.

The next picture is an enlargement of that tiny area of the sky. Now you can see that there is extensive red nebulosity and a bit of blueish nebulosity, and this picture doesn’t even include all of it. It appears so large in the sky that more than 30 full moons could fit inside of it! It is too faint to see with the naked eye; it takes long exposures, like this one of more than 2 hours, to show it well. It goes by the exciting name of IC 1396. Now if you take the area of nebulosity that is outlined in blue, turn it sideways and enlarge it, you will get our last picture.

Here finally is the animal we have been searching for. It is called the Elephant Trunk Nebula, just a small part of IC 1396. The elephant has a yellowish eye which, if you look closely, is a bit bloodshot. But I’m sure he’ll be OK if he can just find the rest of his body, which seems to have disappeared into the clouds! And finally, if you look down near the bottom, you can see a bunny facing left, silhouetted against the deep red light. It almost looks like the elephant is squirting some water out of the end of his trunk onto the bunny Good things come in threes – horse, elephant, bunny – so that’s it for now.

Stay safe,

Carter, (sometime) Resident Astronomer,

Lookout Observatory

 

Click on any image to get a closer look

S163Horsehead-2mx44IPDDColBalStarBrCont3SmooPWCc2Crp
The Horsehead Nebula
E69 22h+60deg IP1mx18-final
Sky from Lookout Observatory in the fall, looking straight up
E69 22h+60deg IP1mx18DDColbalStarBrCon-lines2
Sky from Lookout Observatory in the fall, looking straight up with lines to show constellations
L220IC1396 2mx71curvex8coloradjPWcbg-lines
Area of nebulosity IC 1396
SC16ETrunkNeb IP1mx142DD-final
Elephant Trunk Nebula

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Lookout Observatory shows you Herbig-Haro objects, probably for the first time in your life!

 

Dear Lookout Observers,

If you can find a place with a clear view of the sky around this time of year (early February), and at about 8 PM you face south and look about 2/3 of the way up, you would be looking at the part of the sky shown in the first picture. If you are lucky enough to have very dark skies, the view would be similar to this picture, but without the fainter stars and faint red nebulosity. It is a large piece of sky, almost 60 degrees high and 40 degrees wide. The very top of the picture is directly overhead. Just above center is the bright, yellowish star Aldebaran, brightest star in the constellation Taurus the bull. To the lower left is the constellation Orion the hunter, with his belt of 3 stars and his sword hanging below containing the famous Orion Nebula. In the opposite direction from Aldebaran, to the upper right is a bright star cluster, the Pleiades. Even in light-polluted skies, you could probably still see the Pleiades, Aldebaran, and the brightest stars of Orion. Above the Pleiades, at the very top, is a small red streak known as the California Nebula. It shows clearly in this 25-minute time exposure, but you cannot see it with your naked eye, and it is difficult to see even in a telescope. And finally, notice the small blue box I have drawn near the upper right corner. A close up of this area will be our 4th and most interesting picture. All of the objects featured in this bulletin are within our Milky Way galaxy.

The second picture is a close up of The California Nebula taken with a 420mm telephoto lens instead of the 14mm wide-angle that was used for the first picture. This nebula consists of hydrogen gas about 1000 light years away caused to glow red because it is energized by the bright star below it in the picture. This star is a blue giant, 30 times the mass of the sun, and (including ultraviolet light) is over 1/4 million times as bright as the sun.

The third picture is a close up of the Pleiades taken with the same 420mm telephoto. This is a cluster of stars that formed together about 100 million years ago. The brightest members are all hot young blue stars. The nebulosity around them is caused by their blue light being reflected off of the interstellar dust cloud that they are currently moving through, about 440 light years away. For old time Lookout Observatory fans, more about this cluster was discussed in the February 18, 2015 bulletin.

The fourth picture – taken through a telescope with a 1950mm focal length, a much larger scale than the previous photos – is a close-up of the area within the blue box on the first picture. It is NGC 1333, a cluster of stars immersed in hydrogen gas and dust. It is located about 770 light years away The blue is caused by the reflection on dust of light from large bright blue stars; the red is caused by heated, glowing hydrogen gas beginning to form into new stars; and the dark regions are caused by dense dust blocking the light of stars and gas behind it. If you want to see this as just a colorful picture and leave it as that, that is fine. This report is becoming awfully long!

But if you want to understand more, read on! Giant molecular clouds are the largest objects within galaxies, sometimes several hundred light years across. They contain vast amounts of cold gas and dust, largely molecular hydrogen and helium with small amounts of heavier elements. One such cloud, which lies in the direction of the constellation Perseus, is known as the Perseus molecular cloud and is about 80 light years across. Molecular clouds are where stars are born! Star formation occurs through gravitational contraction in the densest parts of these clouds, and NGC 1333 is the most active region of star formation in the Perseus cloud. It contains hundreds of newly formed low-mass stars less than a million years old.

In stellar formation, as gravitationally contracting gas heats up enough to create a balance between the outward radiation pressure and the inward gravitation, it becomes known as a protostar. Since there are usually eddies of disturbance in the gaseous cloud, additional infalling material spirals in because of the angular momentum from the eddies. As more material from the surrounding molecular cloud pours into the protostar, it may develop narrow jets of fast-moving partially ionized gas at the two poles of the spinning protostar. This fast moving gas is expelled into the surrounding clouds of gas and dust, causing shock waves which cause the energized emission of red light from hydrogen gas, and the result is called a Herbig-Haro object (named after two of the early students of these objects). This shock-induced phenomena is a transient phase of star formation, which typically lasts only a few tens of thousands of years. However, sometimes changes in brightness in the surrounding nebulosity can be seen by professional astronomers in as little as just a few years.

Just above and to the left of the brightest star near the bottom of the image is a string of small red blobs. These are HH (for Herbig-Haro) 7, 8, 9, 10, and 11. Above and slightly right of these is a slightly brighter red blob, identified as HH12. These objects are numbered in order of discovery, so these are some of the earliest identified. HH1 was identified in 1946, and over 1000 have been discovered by now. It is estimated that there may be as many as 150,000 of these objects in our galaxy.

Now you can impress your friends by saying that you have actually seen a Herbig-Haro object! (You don’t have to tell them it looks like just a tiny red blob.)

Keep looking up,

Carter, (sometimes) Resident Astronomer,

Lookout Observatory

 

Thanks to my niece Nicole Balzer, who inspired my interest in star formation details by asking for my help with her college astronomy class. Most information here comes from Wikipedia and from: NGC 1333: A Nearby Burst of Star Formation by J. Walawender et. al., inHandbook of Star Forming Regions Vol. I, Astronomical Society of the Pacific, 2008, Bo Reipurth, ed.

 

Click on any image to get a closer look

E77 4h-0deg 1mx25IPDDColBalBrCont2PWGradremov-crop-NGC1333rsnc
Early Febrary night sky facing south
AT6NGC1499-5mx25coloradj-dd1.0-curvex2winlive-IPBrCon
California Nebula
AT30M45 2mx85IPDDColBalStarBrContx2PWcb3Comp
The Pleiades
SC15&17NGC1333 IP1mx221DD--ColBal-PWCrop2-Name
Cluster of stars – NGC 1333

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Lookout Observatory and the Hubble Space Telescope

 

NOTE: Please read the text before you look in detail at the attached pictures!

 

Of course Lookout Observatory can’t get pictures that look like the Hubble pictures, but I have been curious to see how they might compare. First, let’s look at some of the most basic differences between the largest Lookout Observatory telescope and the Hubble.

Criteria

Diameter of primary mirror
Accuracy of optical surfaces
Subject to atmospheric turbulence?
Therefore, best resolution of detail
Usable wavelengths of light
First put into service                     
Cost to put into service                 

Lookout telescope

11 inches
1/10 wavelength
Yes 
about 2 arcseconds
visible light only
2003    
$20,000 (incl. Observatory)

Hubble Space Telescope

95 inches
1/65 wavelength of light
No
about 0.1 arcsecond
ultraviolet, visible, infrared
1990
$4.7 billion (incl. Launch)

Lookout telescope       vs         Hubble Space Telescope

Diameter of primary mirror
Lt: 11 inches
HST: 95 inches

Accuracy of optical surfaces
Lt: 1/10 wavelength
HST: 1/65 wavelength of light

Subject to atmospheric turbulence?
Lt: Yes
HST: No

Therefore, best resolution of detail
Lt: about 2 arcseconds
HST: about 0.1 arcsecond

Usable wavelengths of light
Lt: visible light only
HST: ultraviolet, visible, infrared

First put into service
Lt: 2003 
HST: 1990

Cost to put into service
Lt: $20,000 (incl. Observatory)
HST: $4.7 billion (incl. Launch)

To see how these differences can show up in the creation of an image, let’s look at Hubble’s most famous image, the Pillars of Creation (first image)

When I first saw this image, I wondered where in the sky this image came from, and I assumed I couldn’t produce an image that was in any way recognizable as these amazing pillars of gas. To answer the first question – where in the sky did this image come from – now look at the first 3 images attached. These are all images I have taken with different size camera lenses or telescopes.

The first is a wide-field view of the summer night sky looking south. If you were in a very dark place in New Mexico – where this picture was taken — you would see something like this (but without the color and without the lines). The color is visible in this long time exposure, but your eyes can’t see color in light as faint as the natural Milky Way. This is the brightest part of the Milky Way, where we are looking right into the center of our galaxy. At the bottom, near the horizon, to the right you would see the stars making up the tail of the constellation Scorpius, the scorpion. The green lines are to help you see the curve of its tail, ending in two stars close together. Near the middle is the constellation Sagittarius, the archer. Many people see the stars as forming a teapot (instead of an archer), with the handle to the left, the spout to the right, and a lid on the top. The green lines are to help you see the stars making this shape. Above it are several pinkish nebulae and clusters of stars in the Milky Way. Notice the blue rectangle that includes two of these pinkish nebulae.

 

The second picture is a greatly enlarged area of this rectangle, where you can begin to see some detail in these two nebulae consisting mostly of hydrogen gas, where new stars are forming, surrounding a cluster of existing stars. In this picture the blue rectangle surrounds the object known as the Eagle Nebula, and it outlines the next image. The third picture shows the Eagle Nebula in more detail, with the center part, which includes dark obscuring dust, surrounded by a blue square. This is where in the sky the Hubble image comes from.

 

The fourth image takes the picture within that square, greatly enlarges it, and turns the square so it is straight up and down rather than tilted. Note that this very great enlargement of my image makes the brightest stars look like large bubbles rather than small dots. This is because the atmospheric turbulence smears the light from the stars in my telescope. Also, the whole image looks fuzzy because the image has been enlarged beyond the practical capability of my telescope to create a sharp image. The Hubble telescope does not suffer from these problems. But there is another difference. My image is taken in visible light, and the color (mostly red) is what you would see if you could transport yourself to see this nebula up close and bright. The Hubble image, on the other hand, uses special filters and then combines different wavelengths of light using specially assigned (artificial) colors – called the Hubble Palette — to bring out the greatest detail in the nebula. It is not how it would look to the human eye if you were close to the nebula.

 

The remaining 5 images (5 through 9) take you on a gradual magical transformation of my image into the amazing detail of the Pillars of Creation produced by the Hubble. So my images are only poor, blurry representations of what the Hubble can produce, but I think they can still be pretty pictures in their own right, and they are created at only 1/250,000th of the cost! I will keep sending you more of my pictures for free, but of course you can get Hubble pictures on the internet for free also. Well, not quite for free. Your taxes help to pay for them. But well worth it, I think!

 

Keep looking up (and paying your taxes),

Carter, (sometimes) Resident Astronomer,

Lookout Observatory

Click on any image to get a closer look

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The Pillars of Creation
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Summer night sky looking south
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Enlarged showing Eagle Nebula
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Eagle nebula in more detail – blue square is area Pillars of Creation comes from
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Eagle Nebula turned with more detail
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Eagle nebula transformation 1
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Eagle nebula transformation 2
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Eagle nebula transformation 3
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Eagle nebula transformation 4
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Pillars of Creation

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Lookout Observatory image, and a personal note

 

Dear Friends of Lookout Observatory,

Scientists love to classify things and make catalogs of their observations. One of astronomy’s earliest catalogs still in use today was created by a Frenchman named Charles Messier starting in 1760. He liked to search for comets, but he kept finding fuzzy objects that looked like comets in his small telescope but didn’t move relative to the stars, so couldn’t be comets. He made a listing of these fuzzy objects so he wouldn’t be misled in his comet searches. These fuzzy objects are called “deep sky objects” today, and they consist of galaxies, gaseous nebulae, and clusters of stars. Since his telescope was small, the fact that he could see them at all means that they are some of the brightest and most interesting deep sky objects that astronomers love to look at. They are identified as M (for Messier) followed by a number. So the first object he listed is M1, and a few were added after his death so that the last one is M110. The famous galaxy in Andromeda is known as M32. Since then many other catalogs have been published, such as the New General Catalog in 1888 listing nearly 8000 deep sky objects. The Andromeda Galaxy in that catalog is NGC 224. Modern astronomers have many large specialized catalogs such as the Principal Galaxy Catalog (PGC), which contains hundreds of thousands of galaxies.

But to return to Messier’s catalog, I have a special fondness for his very first one, M1. It is otherwise known as the Crab Nebula, and it is a supernova remnant, the gaseous shell of a star that blew its outer part away, leaving only a super dense neutron star core at the center. In 1054 AD Chinese astronomers observed a bright “new star,” brighter than any other star in the night sky, that gradually faded over two years. It is now known that this was the initial explosion that started the expansion of the Crab Nebula, and it is the first astronomical object ever to be linked to an historical supernova observation.

What is my personal connection? Well, nearly 34 years ago when Anitra was pregnant with our second child, we decided to search for a larger house. After many false starts we finally found a house we loved and thought we could afford, but there were two better offers ahead of us. But by some miracle both offers eventually proved not workable, and we got the house. I knew this house was meant for us because its address is 1054, the year when M1 began it’s explosion! And we are still living in that house.

This time of year it is too cold to take pictures at Lookout Observatory, so I take pictures from the Southern Outpost of Lookout Observatory, otherwise known as our back yard in Albany, CA, where it is much warmer. So below is a picture of M1 taken from our “M1 house.”

With lots of light pollution in the San Francisco Bay Area, astronomical imaging can be difficult, but modern specialized photographic filters can do wonders, so this 60-minute time exposure taken through an 8-inch diameter telescope shows quite a bit of detail. This object is about 6,500 light years away and about 13 light years across – a size it has expanded to in less than 1000 years. That’s about 900 miles of travel each second!

The brightest part of the bluish nebulosity at the center is arc shaped. If you look just to the left of it and down slightly, you will see two stars very close together. The fainter (smaller) one is below and to the right of the brighter one. This fainter one is the pulsar, a rapidly spinning (30 times a second) neutron star – all that remains after blowing off its great shell of expanding gas. The most striking part of the blown-off atmosphere of the original star is the reddish filaments of hydrogen and other elements. Their exact nature is poorly understood. The bluish color is produced by electrons moving at up to half the speed of light in the powerful magnetic field created by a pulsar — called synchroton radiation. This unique nebula is of great interest to professional astronomers, partly because the complex physical forces operating within it are so powerful that changes in its core can be observed in just a few days.

Keep looking up,

Carter Mehl, Lookout Observatory

 

Click on any image to get a closer look

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The Crab Nebula (aka M1)

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The Autumn Milky Way from Lookout Observatory

 

Dear Friend,

If you live in a rural or suburban area and look at the sky at night to see the Milky Way, you probably do that in the summer time. Nights are mostly warm then, so it can be pleasant to be out. But also that is the best time to see the Milky Way because in the evening the very brightest part is above the horizon, low in the south, while a fairly bright part stretches high overhead. This is the brightest part because we, as residents inside our galaxy, are looking toward the center of the galaxy with it’s bright concentration of stars, star clusters and gaseous nebulae.

More

Click on any image to get a closer look

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The Milky Way
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The Milky Way (x14) enlarge to see full image showing Cave Nebula & Wizard Nebula
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The Wizard Nebula

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More Orion from Lookout Observatory

 

Dear Observer,

Orion is an amazing winter constellation, and I just couldn’t resist showing you a little more of it. On a clear dark night it can be seen about half-way up in the sky to the south at about 8:30 PM. In my last report, on December 10, the second picture was of the central part of Orion showing the Hunter’s 3 belt stars and sword. I have reproduced it here as my first picture except last time we zoomed in on an area just below the lower left belt star, Alnitak. That area contained the wonderful Horsehead Nebula. This time we are going to zoom in on the belt – the area inside the current yellow rectangle – which contains the famous Orion Nebula.

The second picture is at a scale 6 and ½ times that of the first. The first picture was taken at Lookout Observatory with very dark skies. The second picture was taken in Albany, CA, with terrible S.F. Bay Area light pollution. A special filter had to be used to screen out this scattered extraneous light. Because of this difference in sky quality, even though the second image was exposed 5 times as long as the first, and a lens 5 times larger in diameter was used, both images show about the same amount of nebulosity, and both show about equally faint stars. (You can see this for yourself if you enlarge the first image until the yellow rectangle is the same size as the second image.) However, the second picture shows much more detail because at the larger scale it has about 6 times the resolution of the first, and also because special processing techniques were used to bring out the details in the swirling nebulosity and to compensate for the 50-fold variation in brightness that makes it difficult to show the faintest nebulosity without completely burning out the brightest parts.

Much of the constellation of Orion is covered in a huge cloud of nebulosity, and the Orion Nebula (also known as M42) is just the brightest part. The hot blue-white stars embedded in it reflect light off some of the gas and dust, causing it to look blue, and energize other parts of the hydrogen gas to cause it to glow red. Above the Orion Nebula is another blue nebula with darker reddish parts that give it its popular name of the Running Man Nebula. (He’s running to the left.) The Orion Nebula is about 1300 to 1400 light years distant, and it is about 24 light years across. A dark triangular patch near the top points to the brightest (whitest) part of the nebula. In the middle of this is a lumpy looking star, which is actually 4 stars – called the Trapezium – all blurred together in this image. These are just the brightest of several thousand young stars in a cluster spread throughout the Nebula. This is an area of new star and planet formation. Stars are actively condensing out of the gases, and the Hubble telescope has detected hundreds of proto-planetary disks around stars here. It is expected that in about 100,000 years most of the nebula will be gone, having either condensed into stars and planets or else been driven away by outward radiation pressure from the young, very hot stars – a process called photo evaporation. The Universe is far from static! Hang around for a few hundred thousand years – or get reincarnated then – and you’ll see lots of changes.

Keep looking up,

Carter

 

Click on any image to get a closer look

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Central Orion & Orion Nebula (from Lookout)
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Central Orion & Orion Nebula (from Albany)

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