Friday, 29 July 2011
Moon upon a stick (nearly)
Well, a fence. I love the way the moon has just rested itself ontop of it. Unfortunately, I couldn't get anything in focus because the moon was about 20 MILLION times further away than the fence. I managed to make it into the shot, just, but I was severely out of focus. Not the best shot, but it represents a significant moment on the last day of my hol, on July 2 2011, when the new moon returned, signalling the end of another astronomy month. I wonder, did anyone get the second, deeper, hidden pun in the last post?
Thursday, 21 July 2011
Bug
Here's a shining example (ha, ha) of a planetary nebula. This is the Bug nebula (NGC6302). Its unusual shape reveals a ring of dark material around its middle, containing such delights as calcium carbonate (chalk to you and I). Chalk? Surely, that can only be formed from dead sea creatures' skeletons compressed in to rock and up thrust to form, say, the white cliffs of Dover? (I hear you ask). Well no, here it is, out in the reaches of space, in the constellation Scorpius. This is a fine southern object, captured with the ST8300 on the Relay Cassegrain at La Palma. Looks like a scuttling squirrel to me. A red squirrel! I had trouble bringing the dark and light areas out on this, but found that Digital Development in Maxim did a fine job. Then I had to find a clever way of taking out all the red green and blue hot pixels. Interesting little object, whatever creature it resembles.
Friday, 15 July 2011
More pretty stuff
Like a glowing flower in space, the Trifid nebula is suspended in the celestial firmament above the Lagoon nebula in the constellation of Sagittarius the archer. Visually, the colours cannot be seen, and in fact look oddly reversed from that on photographs. This is a wonderful photographic target, that rises high in the sky from mid to tropical latitudes, southwards. The combination of colours arises from general 'dust' that scatters the light, reflecting and enhancing the blue colour of hot stars that light it up, and hydrogen that fluoresces at red and blue wavelengths. Much of the hydrogen light is resonant fluoresent, i.e. glowing back at the extreme ultra-violet wavelengths of 121.6nm and beyond (compared with our visible range 430-630nm). However, this harsh, invisible-coloured light is only detectable above the atmosphere. In this light, our galactic neighbourhood would look vibrant. We just get to see the little red portion (656.3nm) on our photos and, visibly only the tiny fraction that is blue(486.1nm) is detectable to our eyes at night. The picture was taken on a Vixen 4" refractor (with some serious chromatic aberration that I've already reduced) and was just 1 5-minute exposure. Compressed quite badly, or as I would say, Jpegged to high heaven!
Thursday, 14 July 2011
M83
This is a massive, swirling whirlpool that peeks above our southern hedges for a couple of hours on spring nights. However, head south and it rises right up into the starry heavens! So people like me can snap it like over enthusiastic nerds. The southern pinwheel galaxy, or M83, is part of a local little group, and it is associated with Centaurus A. It is about 15 million light years away. All those little red flecks in it are vast nebulae of fluorescing hydrogen. This pic was taken with an ST-8 at prime focus of the 16 inch relay cassegrain at f/6. Four luminance frames of 5 mins each, 4 luminance darks, plus 1 binned red, green and blue. Unfortunately, the dark that accompanied the colour images had some ghost stars on it, hence the inverse colours I couldn't quite get rid of. I have tidied up this image a lot as it is. It's been crudely processed for web use but still looks great! For example the core is totally whited out - sorry. Compare it to my previous M83 to see the sheer improvement.
omega centauri
Wednesday, 13 July 2011
omega centauri
Look at this! I could see it with my naked eye. It was named as a star in Centaurus because it's so bright, but it isn't a star. It's hundreds of thousands of them. It's much too far south to see from Britain. We got a great view of this on the first night through the 16 inch relay-cassegrain scope at astropalma. It was elliptical, which means it must be spinning. But I was impressed enough with seeing it outside through binoculars and then finding it by eye. It's a huge and quite close globular cluster happily orbiting away, floating gently around the middle of our galaxy. I got some close ups too. The little blob above it is amazing too. It is the radio galaxy Centaurus A. I didn't know it was so bright. It looks like an inverted galaxy because it has a bright fuzzy circular background and a dark dusty middle. Obviously you can't see it in this picture, but again I have some close ups, so watch this ... space.
Sunday, 10 July 2011
Amazing place, amazing lens
I thought I'd do another little advertisment for my equipment and holiday. The lens used in this 30 second shot covers from Scorpius to Polaris! This view was from the plinth at AstroPalma looking across to the astrotrak and remote dome. I hired the f/2.8 Sigma 4.5mm 180 degree fish eye from lenses for hire, and it JUST (or maybe not?) focused with my modified Canon EOS1000D. The trouble with modifying a camera is that the removal of glass makes a tiny difference to the focus. Fortunately most lenses focus a bit beyond infinity, but with this one the tiny TINY focal length made the focus point crucial and it only just made it to focus with the ring at full turn. Phew! It is impossible to use live view at night with this lens - no star is bright enough and Jupiter wasn't risen from behind the mountain. I had to find a street light in this dark sky location. Fancy that, wanting light pollution? Mad.
Labels:
Astropalma.,
Canon EOS 1000D,
fish eye.,
gorilla pod,
Gorillapod,
Sigma
Wednesday, 6 July 2011
Astronomy is such hard work
Here, the modified Canon 1000D sits atop the AstroTrak, its sensor receiving aesthetically arranged photons, which hailed from a distant nebula, channeled sweetly through a sigma telephoto lens. The only criticism here is also the thing that makes this photo look good - the damned red light! I lost my bit of tape that goes over it. The 350D's light only came on during data transfer, why did Canon decide to switch it on during the exposure?
Tuesday, 5 July 2011
Backlog
I have had an amazing trip with 100% clear skies. Hence I was spending my time outdoors rather than blogging. However, now I must go to work and process my pics. I have a selection I've done so far of 'exotic' southern milky way objects. Mm-mm-mm! No that's not millimetres, but if you want to know the mm focal length of the instrument used in this pic - it is only 300! Using a starlight express SBIG ST-8 on this little scope gave us this wonderful wide field of Barnard 72, the snake nebula. I have blogged this object before, but never in this much depth or area. This is a single shot of 5 min. I think the scope is around f/6. At the bottom left just off the edge is the star 44 Ophiuchi, which can be used to find these objects. There is a dark kidney bean or cashew nut shaped nebula that is sitting on a star (B74) , going up and right, you come to B70, B69 and then the super dark B68. Over to the left of this field of view is a wonderful big straight dust lane sticking out of the milky way that I could see with my bare eyes!
Friday, 1 July 2011
Bye bye UK sky
I am currently enjoying the stunning delights of La Palma skies at a little observatory on the west of the island. The faintest stars I could see were 6.0 magnitude against the milky way and the atmospheric transparency is great. They also have a light pollution law here. Here is a picture I processed of the Teapot asterism in the direction of the centre of our Galaxy. I hired a 50mm f/1.4 lens, which I put on my modified Canon 1000D and stopped to f/1.6, and without any tracking whatsoever I got 16 pics of length 15 seconds atop a little gorilla-pod. Sagittarius is so high here it is easy to see the lagoon nebula (top) without binoculars, among many other objects: omega centauri, the dust lanes across Ophiuchus are obvious and 'strange' constellations like Telescopium. You can't beat coming this far south for views of the milky way.
Subscribe to:
Posts (Atom)