Thursday, March 14, 2013

Four curiosities

Here are four slightly random images that I'm posting simply because they are slightly quirky, and I am rather fond of them.  The first is the Eskimo Nebula, an example of a rather particular type of nebula called a "planetary nebula".  The name is a misnomer: these objects have nothing to do with planets.  They are the remains of stars much like our sun, that die not with a bang but a whimper.  Instead of the fate of larger stars, which end as novae or supernovae, massive explosions and/or collapse into neutron stars or black holes, smaller stars like the sun simply puff their mass out into space as a series of cosmological death-rattles.  These puffs form a sphere of gas that expands outwards from the star over thousands of years.  They appear as small coloured discs - easily mistaken for planets.  Hence the name.  This particular nebula, the "Eskimo", NGC2392, is a rich blue colour not unlike Neptune.  It's the first example of its type I have photographed.

The next photo is f the Tarantula Nebula.  This is not strikingly exceptional as an emission and diffusion nebula - the (slightly colour enhanced) red elements are glowing hydrogen, while the blue/white sections are gas reflecting the bright light of internal stars.  The one really unusual aspect of this object is that it is outside our own galaxy, in the Large Magellanic Cloud.  It's actually a massive object, and if it were in our own galaxy - say, at the same distance as the Orion Nebula - it would take up half the sky and glow as bright as the moon.

The next is an image of a real neighbour.  This is Jupiter with her four brightest moons.  Actually this is a composite of two images - no single exposure can capture the detail of the bright planet as well as the faint moons, so I had to do a bit of Photoshop jiggery-pokery.

Finally, here is a fuzzy incomplete image of galaxy NGC1365 in Fornax.  For various reasons (clouds, trees, my own inexperience) I've only been able to collect 30 mins of total exposure time where it really needs about four times that much. The reason I'm posting it now is because last November a star in this galaxy (56 million light years away) went supernova.  It was quite bright last year, but is beginning to fade.  The star is still visible - it's the blue dot marked with the arrow.  The galaxy is starting to get too low in the Western sky to shoot properly - I'll image it again next year but by then the supernova will be gone.

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