Thursday, 24 November 2011

The Lagoon and The Trifid Nebulae

Four 5 minute exposures of a favourite region of sky of astronomers was enough to produce this wonderfully colourful and stunning scene. The Lagoon nebula (Messier 8) is below centre, and you can see red hydrogen gas extending out to the left of it. Around that is a dark, twisty channel, with some strange tight turns. That is in turn blocking out the light from the myriad stars of the central milky way in the background. A short hop celestially north lies the trifid nebula (M20), which shows its beautiful colour contrast, and the star cluster M21 appears above that. The darkness to the right is merely apparent due to the blocking of star light by tiny aggregations of molecules, spread thinly, but over such a large volume they collectively cut out virtually all what we see. Other wavelengths of radiation, such as infra red, can shine through these clouds. The 'visible' wavelengths between 0.4 and 0.7 μm were captured with a Canon 1000D with the nearIR-red filter removed, through a Sigma telephoto zoom lens at focal length ~ 300mm, on a well aligned Astrotrak.

Nebulae in Norma

When I was collecting my stellar photons from those sparkly, southern skies last summer I rushed back into my little warm chalet to process the photos. I discovered a new nebula in Norma! Well it had been there all along, but I like to think that. It's a personal discovery. It looks like a swooping giant bird. Apparently it is called NGC 6188, and there is another planetary like nebula towards its north west (upper right), which appears as a fuzzy star on my poor resolution picture. You can see zeta Scorpii at the top, along with another one of my personal discoveries, namely a big faint red patchy ring around the whole cluster. Actually come to think of it, the whole picture is teaming with my new 'personal' discoveries. Dark, straight lines. Who said nature doesn't like straight lines? a physics teacher? Well my last few years of astrophotography have shown me many rows of stars in lines that are too straight to be chance alignments. There are a sequence of giant (I mean HUGE and capitalisation of the letters really is quite an understatement), dark, frigid clouds across the picture. Also, there seems to be a tinge more redness down towards where the tree has made its impression on the moving stack of photos that went into producing this image, but that could easily be an artefact of the processing. The atmopheric extinction of starlight shows up with the lack of light pollution, at such high contrast.

The void

Sorry for not posting for a short while. I've been looking into the void. Unfortunately, I was aiming for the diffuse irregular galaxy IC 1613 in Cetus (/Pisces) and I synchronised the telescope on the wrong star. It wasn't far away, but instead I got an 11 minute picture of the star Hipparcos 5166 and the brightest object of interest in the field was a distant 16.88(blue) magnitude galaxy NPM1G+02.0042 . I haven't even heard of that catalog. I decided to look up the galaxy on deep sky browser ( That's what you get when you look in the wrong direction in the vastness of the cosmos. Nothing. (Well that is if you ignore all those stars).
All this despite the lovely, considerate ("health and safety") lighting the neighbouring village hall provides for their car park (and the local few cubic miles of sky). I have spoken to them about this, but they are in no hurry to change or reposition the lights. What a situation for an astronomical society... when you can't control your local light pollution.