Sunday, 6 February 2011

Looking into the vast pit of darkness

In the south of the constellation of Perseus lies an immense cloud of dust that light cannot penetrate. It is about 600 light years away and weighs more than 10,000 suns, although perversely, the individual dust particles are mostly less than a thousandth of a millimetre across. Beyond the dust is so dark that you can’t see where the edge is, other than the sudden absence of stars. A glimmer of light emerges from the near edge of this cloud. The glow was given the imaginative name of NGC 1333. This was for the purposes of cataloguing, but given its intriguing, ethereal appearance I bet someone out there has called it something. There are some super deep pictures of this on the web, and had I used a red-sensitive camera I would be looking at some sparkly bits to the lower edge of the picture. All that shows up on my picture is a very faint line near the bottom.

The lion's head galaxy

…a lovely galaxy that lives in the head of Leo, the lion. Here’s my new and improved version – like it? It’s still not perfect, but I took one of these before the autoguiding camera and new motors and it’s not a patch on this picture. You can see the smudge of light coming from galaxy UGC 5806 (thanks barnfieldbob) and a couple more faint, tiny (I suspect I really mean distant) galaxies to the lower right. This galaxy is surprisingly easy to see and should have been picked up by Charles Messier before William Herschel discovered it. You can see a giant nebula within this galaxy – NGC 2905, which (I think) is the blob just off to the lower right. The galaxy is classified as SBd (barred spiral) because there is a diffuse, broken bright white bar full of star clusters and nebulae across the centre.

Kohoutek2_1 a.k.a. PK173-5.1…catchy name.

The reason this nebula hasn’t got a decent name is because it is faint and quite amorphous unless, of course, you like one of the names above. The nebula’s feeble 13.8(photographic) magnitude light extends quite a way: over a 2.2 arcminute-sized smear. This planetary nebula is a bit of a cosmic mystery insomuch as it's difficult to tell what type it is. It was difficult to photograph, mainly because I aimed my telescope perfectly, but it appeared after development at the lower edge of my picture. My original calibration was with a poor flat field, which was not good at the edge, although I had done a good job processing: blurring, increasing contrast and masking the stars, background removal etc., etc.. You can see the purple noise where the background subtraction went a bit wrong and the glow on the right from the camera sensor’s amplifier. I show you here the cropped edge of the picture where this glob of stellar snot was hiding. There’s a distinctive pattern of stars on the left that one could use as a sign post. I might try and find this ‘faint fuzzy’ visually on a good night, as it is 12th magnitude to the eye and high in the sky just below the outline of Auriga the charioteer.