Astronomy

Pictures of galaxies, nebulae: which way is up?

Pictures of galaxies, nebulae: which way is up?


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We are used to viewing pictures of the Earth and the planets with their North Pole pointing towards the upper portion of the photo. But when a space telescope snaps photos of cosmic entities, do they rotate the photo around to get an attractive composition? Is it a subjective rotation, or are there rules? Which way is up?


Images are often presented with (Earth's) North at the top but there is no correct orientation. For example, in this image from the VLT north is 0.1 degrees from the vertical, the sidebar on the image page has details on the position, field of view and orientation.

However, this image from the same telescope has been rotated left 9 degrees, which is likely an artistic decision.

Amateurs also regularly align the cameras on their scopes so that north is up as it can make it easier to diagnose tracking problems. However, it's fairly common to change the camera alignment on the telescope to frame particular targets or groups of targets.

Many classes as astronomical objects, such as elliptical galaxies, irregular galaxies or nebulae don't have a well defined or known axis of rotation, which is why Earth's poles are used as a reference.


12 Incredible New Images of Galaxies and Nebulae from the Hubble Telescope

Look up to the sky with the unaided eye and you’ll see lots of specks and globs that look mostly like stars. On closer inspection, though, some of those dots refuse to resolve, smeared out on the night sky.

Famed astronomer Charles Messier noticed these objects while studying comets—indeed, they looked like comments standing still in the sky, according to NASA . He therefore called these imposters “objects to avoid,” and catalogued them in his list of 103 “Messier Objects.” That list has since been expanded to 110.

It’s a good thing scientists didn’t avoid the imposters, though. It turned out to contain some incredibly important astronomical objects, smeared out because they consisted of not one, but many stars. The first comet-looking thing, M1, was the now often-studied Crab Nebula . His catalogue also included the Andromeda Galaxy (M31), the pinwheel galaxy often used as a Milky Way lookalike (M101) and the Whirlpool galaxy (M51a). You, too, can spot many of these objects with an amateur telescope .

The Hubble Telescope has made spotting these objects simple, and has creating some breathtaking images along the way. That includes the Eagle Nebula, also called the Pillars of Creation or M16, perhaps the most famous nebula ever observed.

Hubble has spotted 93 of these objects. They’re not true color, since Hubble takes single color images at a time. Usually, several observations at different wavelengths are combined, or colors are added during processing to squeeze out meaningful information. Hubble’s added another twelve new images—you can take a look below and browse the rest here .


The Stingray Nebula is a rapidly evolving planetary nebula located 18,000 light-years away in the Ara constellation in the southern hemisphere of the sky. Approximately 130 the size of our solar system, the Stingray Nebula is the youngest planetary nebula ever discovered.

Stingray Nebula in Ara Constellation


Double Stars in Camelopardalis

These are the brightest and easiest-to-find double, triple, and quadruple star systems in the constellation Camelopardalis. Also see all star clusters.

    1. Star system
    2. Magnitudes
    3. Type
    1. 1 Camelopardalis
    2. 5.8, 6.8
    3. double
    1. 32 Camelopardalis
    2. 5.3, 5.7
    3. double

Our moon

This winning picture by Laszlo Francsics shows the lunar surface in a new, hyper-saturated way.

The Tycho Crater, named after Danish astronomer Tycho Brahe, has a bluish shade. This is typical of the younger craters on the Moon, with estimates dating it as 108 million years old.

The runner-up image in this category is Jordi Delpeix Borrell's close-up of the moon's face.

This photograph shows a chain of walled plains - large craters whose floors have been filled with lava.


Nebula

A nebula is cloud of dust and gas in space. The term 'nebula' comes from the Latin for fog or cloud.

Historically, the term nebula was used to describe any object that appeared cloudlike outside of the Milky Way, including other galaxies, but a true nebula is a cloud of dust and gas. The gas normally consists of hydrogen, helium, and ionized gases. They can range in size from millions of kilometers in size, to many light years across. While nebulae can be very large in size, they aren’t very dense. Most nebulae are described as diffuse nebulae, meaning they have no clear edge or boundary.

Stellar nebulae are clouds of dust and gas that will ultimately form a star. The dust of gas collapses due to gravity. As the cloud decreases in size, the heat increases as the size of the cloud decreases. The temperature increases because some of the gravitational potential energy is converted to thermal energy. Once it reaches a critical temperature and a critical density, nuclear fusion can occur.

Another type of nebula is called a planetary nebula. This term was first used by the British astronomer William Herschel in the 16th Century. Planetary nebulae happen around stars with a similar mass to our Sun, towards the end of a star’s life. As the star’s core collapses, a shell of gas is ejected. Stars that are very large undergo a much more violent process towards the end of their life cycle. Large stars become unstable after they have used up their nuclear fuel, resulting in a large explosion known as a supernova. These explosions are huge and can often outshine whole galaxies. The remnants of these explosions will form nebulae.

The Hubble Space Telescope has been used to take images of different nebulae. These images are some of the most impressive that have been taken using the space telescope.

How Do I Use This?

The picture encyclopedia storyboards have easily digestible information with a visual to stimulate understanding and retention. Storyboard That is passionate about student agency, and we want everyone to be storytellers. Storyboards provide an excellent medium to showcase what students have learned, and to teach to others.

Use these encyclopedias as a springboard for individual and class-wide projects!


The astrophotographer who snaps images of stars and galaxies from his window

SINGAPORE: One of the first pictures Ivan Bok took through a telescope is the Orion Nebula. It is one of the brightest nebulae located in the Milky Way, visible to the naked eye in the night sky.

“For most people, the first thing that (they really remember) is looking at things like the moon and Saturn,” said the 26-year-old National University of Singapore student.

“But the reason it was this more obscure object (for me) was because I saw it in books. I always thought it was somewhere within the realm of professional astronomy that amateurs like us will never be able to see.

“But turns out it’s actually a really popular amateur target. Even under Singapore’s light-polluted sky, you can still see it.”

Although his attempt at taking a picture of the nebulae - a cloud of interstellar gas and dust - was “horribly blurry”, this was what “hooked” him on astrophotography.

Ivan has taken over a hundred pictures of planets and galaxies, accumulated over his decade-long interest in astrophotography.

The Fighting Dragons of Ara, also known as the Rim Nebula, was taken from Ivan's window (Photo: Ivan Bok).

FROM A YOUNG AGE

Even as a child, Ivan had been “very interested in science”. He remembered reading astronomy books while in primary school and got his first telescope at the age of eight.

“It was just this refractor from Toys R’ Us,” he said.

His first “real” telescope came in Secondary 2, which he bought from the Singapore Science Centre for S$400, with his own savings.

“Even then, it wasn’t cheap for a secondary school student,” he said.

“Back then, when everybody was buying a PSP (Playstation Portable), I don’t know what went through me, I bought a telescope.”

An image of the Orion Nebula taken by Ivan. (Photo: Ivan Bok)

It was “exciting”, the first time he got to try it out. He remembered that the night sky was cloudless when his father brought him to the ground floor of their flat to set up the telescope.

But Ivan could not remember what was the first object he saw through the telescope, saying it was probably either a planet, or the star Sirius.

He only started taking photographs of the night sky when he got his next telescope three years later. The S$2,000 telescope was computerised. Its tracking mount – which allowed the telescope to automatically track celestial objects across the sky – made it suitable to take pictures with.

DEVELOPING A GOOD IMAGE

By his own admission, the photographs he took for the first two years were “pretty bad”.

“I was doing this entirely alone and I didn’t realise I could shoot from my window,” he said, which meant that opportunities to practice were few and far between.

His equipment also wasn’t ideal for taking pictures of deep sky celestial objects, outside the solar system. He did not use filters either, which meant that he got the “full brunt of Singapore’s light pollution” in his shots.

The filters Ivan uses helps to block Singapore's light pollution. (Photo: Cindy Co)

The pictures he took improved after he received pointers from someone in the local astrophotography community and upgraded his equipment.

Ivan shared that although the person used basic equipment, he was able to get good images because he spent over an hour shooting the same object.

Long exposures would allow him to collect more light from the objects, and thus more detail.

That inspired him to try it out with his telescope setup, which he has aimed at the heavens from the window of his flat.

Ivan said that the long exposure made “a whole world of difference” after he combined the images digitally.

AN ART AND A SCIENCE

As someone who is interested in both art and science, astrophotography combines the best of both worlds for Ivan. While he has applied his technical know-how to use his telescopes - which he has spent about S$20,000 on - he gets to express his artistic side with the colours he adds to the images.

When he shoots, he creates "false colour" images, which are commonly used by astronomers to make images more comprehensible. "False colour" images are not the same colours that the human eye would see if it were to look at the celestial object directly.

“But this doesn’t mean that the image is fake in that sense. It’s just that the colours that we choose represent a different truth behind the image,” he said.

An image of the Andromeda Galaxy by Ivan. (Photo: Ivan Bok)

Images in false colour would be based on what the photographer finds “aesthetically pleasing”, Ivan said.

“So if you give two astrophotographers the same base data set, you’ll never get an identical image out at the end of the day.”

“ALWAYS A JOURNEY”

Even though he has had his pictures published in two magazines - Astronomy, and Sky and Telescope - Ivan still sees room for improvement.

“It’s definitely always a journey. So there’s never a point where I feel like I ended what I want to do, and I think that’s the beauty of it,” he said.

Other than shooting from his window, Ivan hopes to be able to shoot from dark skies overseas, which gives him a larger variety of objects to shoot. (Photo: Cindy Co)

For now, he is just looking forward to being able to shoot from dark skies, where there is little or no light pollution. He also hopes to capture the images of distant galaxies and nebulae.

When asked if he would consider using his hobby as his primary source of income, Ivan’s answer was a firm "No".

The double degree Business and Engineering student said that he would rather “segregate work and hobbies” to maintain a balance.

“It is contrary to what a lot of people say. Do something you love and never work for another day. But I feel like if money or livelihood is tied to my enjoyment, it’s going to diminish my enjoyment,” he said.

Instead, he hopes to pursue a career in the corporate world.

But it is the emotional connection that keeps him going with astrophotography, he said.

“I really, really enjoy astronomy (as) it fulfils an innate sense of curiosity about the universe … It creates this connection with the natural world.

“It really drills down to, on one hand, mankind’s insignificance, and on the other hand, what there is that we don’t know. I think these discoveries are what keeps humans progressing.”


Images of Galaxies, Nebulae, & Planets with telescope, camera, techniques

Images on this site of galaxies, nebulae, and star clusters were taken mostly with the Starlight Xpress SXV-H9C CCD color camera and the Meade DSI I color camera on either a Alt/Az mounted Celestron 8 inch telescope (Nexstar 8 GPS) or a Celestron 11 inch XLT telescope mounted on an equatorial mount. Some of the more recent images used guiding. At $299 originally (now $95) the Meade camera is the least expensive way to start in astrophotography and still get reasonably pleasing results. The planet photos here were taken mostly with the Philips ToUcam Pro II web cam. This camera or the similar Celestron Nextimage are excellent and inexpensive (

$99-$160) cameras for the planets and the moon. Some of the photos on this site are not "perfect" and the descriptions of the image taking details will point out the problems. Other telescopes used are Meade ETX-90, Orion ED80, and Coronado PST.

Data is collected from the cameras on a Dell laptop computer ($700) and transfered to a Dell desktop for processing. Data can thus be processed on one computer while more data is being collected at the same time on the other. Software used for data collection and image processing is that included with the cameras, the excellent freeware program Registrax 4, and the commercial programs Paint Shop Pro 9 and AstroArt 4.

In the spring of 2006 I purchased a used Starlight Xpress SXV-H9C CCD camera for $2000. This camera has more pixels and a wider field of view than the Meade DSI along with thermoelectric cooling of the CCD chip. I am using AstroArt 4 for data acquisition and processing along with Paint Shop Pro 9. You will be able to compare the results from the two cameras and decide which is a better value.

In the winter of 2006-2007 I got a CGE mount on sale so I could add a piggybacked Meade DSX-90 telescope to the Celestron 11 inch for guiding with a Meade DSI camera. This has allowed exposure times of up to 5 minute per subframe so far.

In the spring of 2007 I purchased a Meade DSI pro for guiding. It also occured to me that it could be used with my Orion ED80 on my CG5 mount (casually polar aligned) for a "Grab and Go" imaging set up. Using the Celestron power tank and my laptop on battery power I could take a few images without needing AC power. These black and white images are listed in a separate catagory above.

In 2010 and 2011 I traded in my C11 CGE mount system and sold my Orion 120ED CG5 mount system due to back problems. I now use a Stellarvue SV105T and Lunt 60HaT solar scope, and still have my C8 but sold the HyperStar lens. These all can be used nicely on an iOptron MiniTower mount. I can take short exposures with the H9C camera on the Stellarvue and C8.

In the fall of 2011 I purchased my first video camera. This allows almost real time (up to 56 second integrations) views on a 9" DVD player. This is a great setup for public star parties. I can also capture images with my computer, now a Toshiba with an Intel Core i7 processor.


Astronomers Snap Photo of Beautiful Planetary Nebula

Astronomers using the Gemini South telescope on the summit of Cerro Pachon in Chile have taken a picture of CVMP 1, a planetary nebula located some 6,500 light-years away in the southern constellation of Circinus. Also known as PN G321.6+02.2 and Marsalkova 252, this object emerged when an old red giant star blew off its outer layers in the form of a tempestuous stellar wind. As this cast-aside stellar atmosphere sped outwards into interstellar space, the hot, exposed core of the progenitor star began to energize the ejected gases and cause them to glow.

This image, taken by the Gemini Multi-Object Spectrograph on the Gemini South telescope on Cerro Pachón in Chile, shows the planetary nebula CVMP 1. Image credit: Gemini Observatory / NSF’s National Optical-Infrared Astronomy Research Laboratory / AURA.

Planetary nebulae like CVMP 1 are formed by only certain stars — those with a mass somewhere between 0.8 and 8 times that of our Sun.

Less massive stars will gently fizzle out, transitioning into white dwarfs at the end of their long lives, whereas more massive stars live fast and die young, ending their lives in gargantuan explosions known as supernovae.

For stars lying between these extremes, however, the final stretch of their lives results in a striking astronomical display such as the one seen in this image.

Unfortunately, the spectacle provided by a planetary nebula is as brief as it is glorious. These objects typically persist for only 10,000 years — a tiny stretch of time compared to the lifespan of most stars, which lasts billions of years.
These short-lived planetary nebulae come in myriad shapes and sizes, and several particularly striking forms are well known, such as the Helix Nebula.

The great diversity of shapes stems from the diversity of progenitor star systems, whose characteristics can greatly influence the ensuing planetary nebula.

The presence of companion stars, orbiting planets, or even the rotation of the original red giant star can help determine the shape of a planetary nebula, but we don’t yet have a detailed understanding of the processes sculpting these beautiful astronomical fireworks displays.

But CVMP 1 is intriguing for more than just its aesthetic value: CVMP 1 is one of the largest planetary nebulae known the gases making up the hourglass are highly enriched with helium and nitrogen.

These clues together suggest that CVMP 1 is highly evolved, making it an ideal object to help astronomers understand the later lives of planetary nebulae.

By measuring the light emitted from the gas in the planetary nebula, astronomers infer that the temperature of CVMP 1’s central star is at least 130,000 degrees Celsius (230,000 degrees Fahrenheit).

Despite this scorching temperature, the star is doomed to steadily cool over thousands of years.

Eventually, the light it emits will have too little energy to ionize gas in the planetary nebula, causing the striking hourglass shown in this image to fade from view.


Credits

The Edwin Hubble presentation is made possible by support from The Barra Foundation and Unisys.

This website is the effort of an in-house special project team at The Franklin Institute, working under the direction of Carol Parssinen, Senior Vice-President for the Center for Innovation in Science Learning, and Bo Hammer, Vice-President for The Franklin Center.

Special project team members from the Educational Technology department are:
Karen Elinich, Barbara Holberg, Margaret Ennis, and Zach Williams.

Special project team members from the Curatorial department are:
John Alviti and Elisa Graydon.

The project's Advisory Board Members are:
Ruth Schwartz-Cowan, Leonard Rosenfeld, Nathan Ensmenger, and Susan Yoon.