Saturday, January 28, 2012

Speeding sand

     Walking on a beach in a remote part of the coast one could sometimes fail to notice the sand. Still, each grain (under specific conditions, like entering the atmosphere at tens of kilometers per second) can not only attract attention but also bring a smile on the face of the onlookers. A meteor!

     The comparison with a grain of sand usually implies insignificance.  But who says that a grain of sand is not much?

     Especially when it shares the orbit with it's parent comet, like these Perseids racing with 109/P Swift-Tuttle.

Tuesday, January 24, 2012

Glorious home galaxy

We live in a rather large barred spiral galaxy, between the Sagittarius and Perseus arms. 
I took this photograph from one of the best places on the planet to try seeing it in it's full glory, the Las Campanas Observatory in the Atacama region. We're not in the center of the Universe, our planet is an unimportant speck of dust, our Sun is a little star by cosmic standards, but at least we live in a big and mighty galaxy :) 

Visually it was even more impressive!

Thursday, January 19, 2012

Crescent nebula

The story of a Wolf-Rayet star

       These special massive stars (>30 times the solar mass) are in their later stage of evolution, about to become a supernova. Due to the fact that for a few thousand years in this period they lose a lot of mass through stellar winds, more than half of the known WR stars are surrounded by nebulae.

       Crescent is one of these nebulae, a supernova cocoon where a lot happens. It's 4700 light years away (!), measuring about 20 light years across. The star creating this object, WR 136 ( or HD 192163) is a member of the Cygnus OB1 association, a cluster of young stars in that constellation.

    Wondering why I said that this star is nearing the end of it's life while being part of a young cluster of stars? The answer lies in the amazing fact that the more massive a star is, the less time it will live! This way, a 0.1 solar mass star can fuse nuclei together for even 1000 billion years while one as massive as 100 suns will destroy itself in only a few hundred thousand years, a blink of an (cosmic) eye!

Behold, NGC 6888:

Wednesday, January 18, 2012

The Whale galaxy

NGC 4631

The interaction with its smaller neighbor produced an intense burst of star formation. So many were created that lots of supernovae exploded near the center of the galaxy, pushing gas out of the galactic plane and creating an enormous corona of X-ray emitting gas (because it's so hot).

...And... the result of the last three clear nights in our foggy-cloudy Bonn:

Note: Due to the fact that I'm incredibly impatient to share a picture when I have a preliminary result (always far from what can be eventually achieved with the data), I won't wait for a couple of months until I get my hands on Photoshop and have a lot of time to properly process it. But one day, the Whale will become better!


If your first thought was: "Ah, the Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes!" then you have a definite + and a big accomplice smile from me :)

 During my first observing run at the Cerro Tololo Inter-American Observatory I had the chance to look from above at this network of  6x0.41m telescopes, always ready to observe simultaneously and in multiple wavelengths bright afterglows of Gamma Ray Bursts. 

Monday, January 16, 2012

Winter - time - play

Two brand new time lapse videos of the German skies. 

    First, an initially very foggy night turned out to be crystal clear once the Moon came up. It was cold and when the Sun also joined the breathing of the city became visible. 

    You MUST view them in super HD and at full screen!

A second short time lapse shows the skies at the Hoher List Observatory during a few hours of deep sky observations a few months ago. Hello Winter!

Thursday, January 12, 2012

Pacman nebula

     It is slightly larger than the field of view, but I know that the hard-core gamers out there immediately saw the Pacman :)

     NGC 281, it's other cool name, is a region in the Perseus spiral arm of our galaxy where Hydrogen got excited with the presence of so many bright stars in and around it. These are part of a very young open cluster and after some time more and more stars will form, eventually consuming and dispersing all the available material for star-making factories like the Pacman.

     The black, small, condensed areas are called Bok globules and have a few solar masses of material in a region of about one light year: this is a place where it is thought that star formation takes place. 

Wednesday, January 11, 2012

Hoher List Observatory

     It's winter. And you're close the the most densely packed region of Europe (with humans, of course).
     Still, this is what you can see if you drive for a couple of hours :)

     The winter skies always bring good memories to me: this is how the sky looked like when I started with observational astronomy. Sure, Jupiter was in Gemini then and Capella reached the exact zenith from that location, but it's close enough to what I was looking at. It never gets old, seeing Orion fiercely staring at the Bull (Taurus, who stares back!), with his two dogs (Canis Major and Minor) running to his aid and of course, hunting a Rabbit in the process (Lepus), seeing Andromeda desperately seeking salvation from the Sea Monster (Cetus) and Perseus bravely aiding her with his newly acquired Flying Horse (Pegasus) and Demon Eye (Algol). All this while her parents, Queen Cassiopeia and King Cepheus look at his awesomeness with hope. Yet, they all run away as the night progresses as the big, bad Scorpius comes out and tries to catch someone! 

Mythology and stars, connected by stories thousands of years old. 

Monday, January 9, 2012

The Perseus Galaxy Cluster

      There are over 100 galaxies in this image spanning about half the area the Moon is taking up in the sky. Many more are not visible in the picture (thousands more!): this fact makes the object you're looking at one of the most massive structures in the whole Universe! If one galaxy has in average 10 billion stars, then you're looking at 100 000 billion such objects (don't forget the stuff that you don't see, like gas and dust). And it's only 250 million light years away :)

      NGC 1275, the brightest blob in the lower left, is actually composed of two galaxies: a massive cD (giant elliptical) and a smaller one falling towards it at 3000 km/s (it lies in front of the cD as seen from our viewpoint and it's called by astronomers the HVS - the High Velocity System). There are filaments of matter up to 20 000 light years long extending from the cD which appear to be pushed away by rising bubbles or relativistic plasma produced by the central active galactic nucleus. Each of these filaments is as massive as a million suns!

    A... note for musicians: do you want to "hear" a low tone? Then maybe spending some time trying to hear the B flat, 57 octaves below the 440 Hz. Or maybe just look at it, the time between subsequent pressure waves is about a million years. 

Elephant's trunk

      Almost always when something stands between me and the stars I get rather annoyed, to put it politely. Especially when it's a cloud. 

     Well, this is one of those few exceptions: a dense cloud of gas and dust, minding his own business in our galaxy which does exactly that, and... I love it! :) 

    This particular cloud can be seen in the (Earth) cloud-less nights in Cepheus and it's about 2500 light years away. Inside it there are a few very, very young stars, only a few thousand of years old and a few more forming right now. The bright rim you can see in the lower part of the nebula is ionized gas by light from a massive star just outside the field of view, in the lower part of the image. In some time from now, this dark cloud might start to look a lot like this.


Wednesday, January 4, 2012

Thor's Helmet

Unlike other things, their end can create and bring beauty.

        I'm talking about massive stars, close to dying: the Wolf-Rayet type. In their last moments, literally giving their last breath (through a wind that is super-fast (>2000 km/s) and massive (~10^(5) solar masses per year)), WR stars can create such a nebula around them. The shape of this one is thought to be this complex due to interactions with a cloud of gas and dust already present in the vicinity of the star.
       It's so hot (~50 000 K) that it makes everything glow around it, the nebula is 30 light years in diameter!

    The name honors truly the object: when I look at it I see this furious, massive, pre-supernova stage star embedded in a cocoon of hot gas while plowing through the galactic interstellar medium. A Thor-like star (quick to anger, ready to explode at any time) wearing a gigantic cosmic helmet while running around in the galaxy through all those clouds of gas and dust...

Luna, the Moon!

         I usually don't like the Moon (unless it's a silver crescent embedded into the reddish twilight) because it helps to hide even more stars from us than light pollution. But sometimes I cope with the light it scatters through the atmosphere while it's close to being full and take a good, looooong look at it. For billions of years, applied celestial dynamics and collision physics created this:

       Isn't that completely amazing?!

The Pillars of Creation

What better way to start my blog than posting one of my dearest sample of photons?

      One of the most famous regions in the sky, the Eagle Nebula is situated about 7000 light years away in the constellation Serpens (Cauda) and is a breathtaking birthplace: this is where stars form! The pillars formed when young, very hot stars eroded their environment through fast winds and pushed material away with their radiation pressure.

    In this image there are many hours of data and even more hours of processing work. It was an early, cold morning when I tried to capture some light from this region of our galaxy and when the first Hydrogen-alpha frame was downloaded into the computer all my sleep ran away, fast!. Until late twilight I kept taking data, enthusiastically waiting for the next frame, seeing the signal slowly growing out of the noise. 

     Tremendous morale boost after these endlessly clouded German skies.