Thursday, February 21, 2008

The Great Orion Nebula

This is probably the most looked at telescopic "deep sky" object in the night sky of the northern hemisphere, though Deep Sky may not be the best description of the object as it's really rather bright as far as these things go! Visually you can see a definitive glow of gas in the centre of Orion's belt - you can certainly tell it's not stellar in nature. Through the eyepiece, I tend to see a tenuous curls of green glowing gas, studded with the central stars that make up the trapezium. The low elevation in the sky makes viewing it quite different every time depending on the local sky conditions, and the fainter outer curls seem to pass in and out of my vision as I look. Sometimes I wonder if I'm wishing the details to come out, but the structure is very much real!

I have tried to image M42 in the past with a modified webcam - this bought out the central region not too unlike what I could see visually, but with the added dimension of colour - a lovely pinky red tint. Moving on a few years, I now have my trusty Canon 10D, and with a motorised Vixen mount on loan I though I'd point my ED80 refractor towards the hunters belt to see what I could capture with a DLSR set up.

Boy, I was not disappointed by the results! From the first single frame I knew that I was going to get a very satisfying result! I proceeded to take a series of 40 30 second exposures, complimenting them with 20 dark frames, and ran it through Deep Sky Stacker and PixInsightLE to bring out this result. It even captured the "Running Man" nebula, NGC1977, at the top of the frame. It is called such because the dark lanes running through the nebulosity look like a man running - something that is quite subtle on this image but still visible with some imagination! Depending on your monitor settings, you may be able to pick this out - a lot of TFT's tend not to have linear brightness intensities across all shades of grey so it may look a little dark.

This was a milestone for me, and a great little test for my camera, mount, and overall work flow. When I get my Astronomics CLS light pollution filter, I shall take longer subs and see just how far the nebulosity can be traced. For now though, more 30 second subs and a good set of flats can only enhance the image further ... I just need some more free time and a clear night :)

Saturn and its Closing Rings

I have not had a lot of time to observe over the past few months, but the opportunity came up the other week to get a telescope out to show my father in law some of the delights of the night sky. Top on the list was Saturn, and I was amazed to see just how much the rings have closed since I last got a good look at the ringed planet.

This image was taken with Bristol Astronomical Socities' newly donated 8" scope (thanks Jan!). It needs collimating, and the helical focuser has a bit of play in it, so a little attention will have to be paid to the scope to get it finely tuned. The result was still worth the effort though. I'm not sure on the make of the scope, but the mount is a Vixen, and it's pretty darn good at tracking too! The whole thing is made of aluminium, so it a lot lighter than my steel EQ5 mount - and thus infinitely more portable. It looks to be a good imaging platform for exposures of a minute or so with good polar alignment.