Monday, 31 January 2011

Through the telescope

Here’s my best picture yet of M97, the owl nebula that doesn’t look like an owl. It looks smoother than most of the pictures on this blog because it is linear, i.e. I haven’t messed around with the brightness scale to enhance the secret, dark, hidden objects. The view of this beautiful green planetary nebula is much more than you will see through the telescope; the three stars at the centre are very difficult to see visually. In order to gauge the brightness, the stars to the left and right of the nebula are 12th and 14th magnitude, and the 15th mag star just below has a 16th mag galaxy hiding behind it! I also picked up the edge-on sliver of a galaxy to the left. A faint patch of red can be seen on the edge in the direction of this galaxy. This is a lovely big planetary, glowing mostly in light from the bizarre space form of oxygen: O2+ ions. For those of you with an interest in chemistry, this is a state that does not exist in detectable levels on earth. The shape looks like two overlapping circles offset diagonally a little way. This is possibly just a near top down view of the two symmetrical lobes that were ejected from the dying star thousands of years ago. Image was 6 x 90 seconds at f/3 on the 20” telescope.

IC 1470

Just over the Cephean border from M52 and the Bubble nebula in Cassiopeia lurks IC1470. Down on my charts as being 15 arc minutes wide, it is just a little pink square with one bright half containing a star. There is some structure within it, that’s hard to see with the fuzziness of the optics. There are as you may notice some bluish patches of what looks like ‘reflection nebulae’, where starlight is scattered off interstellar dust. A couple of smudges appear at centre left and a curly patch next to the bright blue star on the right. I guess this nebulous richness is because we are looking much further across our galaxy into the outer (Perseus) spiral arm where things therefore look smaller and closer together. I still find it amazing when stars line up into pretty patterns, like the beautiful curly ‘X’ at centre left just under the faint blue nebulae. Also there is a curly arrow shape just above centre. I wonder if this is just chance alignment, or are they associated?

Wednesday, 26 January 2011

Moonset 8-1-11

As I ascended into the dome and opened the shutter, I noticed that the moon was close to setting. I lowered the big scope down to near horizontal and used the hand-pad to follow the moon. This 2 second untracked shot at ISO 400 and f/3 allowed me to capture enough of the moonlight, which was by then an attenuated orange colour, so that it scattered off the edges of the branches. The tree in question was across the road on the other side of a large field 227 metres away. The difference in focus between the moon and the tree was enough to dilate the lunar crescent into a fat banana.

The Perseus Galaxy Cluster

I count 55 galaxies, although some of those smudges that look like faint stars are probably galaxies as there are supposedly 190 of the blighters. This is one massive concentration of galaxies. The cluster is centred on galaxy NGC 1275, or Perseus A, and is surrounded by a cloud at a temperature of millions of degrees, in which bubbles of relativistic plasma are being produced from the galaxy’s active nucleus. These are effectively sound waves at a pitch of Bb, 57 octaves below middle C! To the right of the two large ellipticals at the centre lies a galaxy with some strange structure that I can’t quite reveal with my equipment and 14 1-minute exposures.

Tuesday, 25 January 2011

NGC 2174 - the monkey

For something I had barely thought I could image, this thing surely turned out to be a beautiful assortment of coloured environments. It is also a well balanced photograph. There’s the blue Hydrogen-beta coloured smooth centre, dominated by the bright (7½m) star. Surrounding that are some dark grooves, some dark blobs, intensifying towards the pinkish-red edge, where some surrounding foreground dust blocks the light from us. Floating out towards the top is a smallish brighter nebula, with a different shade of blue, and a similar companion lying out in the dark dust cloud. And then over to the left is a strangely angular piece of deeper blue glowing cloud with its own little cluster. From this angle and zoom the nebula doesn’t live up to its name. The monkey nebula is a wonderful half degree sized nebula located above Orion’s right arm.
Later: I heard tha apparently the monkey's head is looking to the right with an upturned nose - doesn't look much like a monkey to me!

The toothpaste nebula

In this photograph, the small, spectrally dispersed planetary nebula IC 418 in Lepus has appeared to jump, creating a stripe of a familiar looking toothpaste.

IC 1871, well... part of IC 1871.

I plonked the lumbering 20” light bucket where I thought the middle of a nebula was. After processing 15 exposures of 30 seconds I could see a swirl on the right hand side of my screen. Only after seeing that my flats weren’t up to the job and retaking them using diffused moonlight, I just revealed some very faint, large structure, covering the whole frame. Some of the patches may still be due to optical differences but I have missed the main other structured part of this nebula (to the lower right) and the nebulosity in this part is very dim. It just shows that this nebula is far too big to capture with the ~40 arc minute sized field of the Canon on a 2.4 metre focal length scope and I should check exactly what I’m pointing at in future (difficult at the time). Plus it is far too red for much of its light to penetrate the cyan filter glued on top of the camera’s sensor.

Scary blobby pink “Space Thing” with eyes!

Yes. I’ve taken a picture of the time tunnel they ran into in Star Trek. Let’s hope Earth doesn’t get sucked in. I started by departing on a walk starting from the star 4 Cassiopeiae, hopping across to Cluster M52 and thence locating the “Bubble” Nebula. In the past, on a visual scan of this area with an ultra high contrast filter, I kept happening across a nebula in the other direction to where the Bubble Nebula was. This was NGC 7538. Recently I got the chance to take its picture.

Sunday, 2 January 2011

Giant Space Jellyfish!

I focused and tracked on the bright star Propus in Gemini (η Geminorum), and got a set of 1 minute exposures of the area to its left, as it was rising in the eastern sky. On the first night I got home, processed the image only to see intriguing, blobby strands of red across the picture like the tentacles of a giant jellyfish. I went even further to the left on my next observing session and this time picked up the jelly-like body. I had a lot of trouble combining the two pictures, and the overlap was at a strange angle, as the two images were taken at different times. I’ve cropped and rotated it so Propus glints beautifully as if lighting the jellyfish from below.

The moons of Saturn

I was looking back over last year’s images and discovered I’d managed to reveal the Saturnian moons Mimas and Hyperion. Admittedly, Hyperion, a porous moon full of deep holes is hard to see, but is one of the blobs of ‘noise’. I had to chop off Iapetus, which was clearly seen, along with a 13th magnitude star, way out to the right. This view was obtained at 2250UT on 10 May 2010. From left to right you have: Titan, Rhea, Dione with Hyperion pretty close to its lower left, Saturn, Mimas, Enceladus. Tethys was behind the planet at this time. The shallow ring angle and reasonable seeing helped pick out these tiny moons. This brings my Saturnian moon total to 9. The outer moon, Phoebe, on an earlier image, is now thought to have produced a huge outer ring causing Iapetus’s dark side. Mimas is an amazing object, with a huge crater like the death star, and it causes the Cassini division in the rings.

An artistic view of the Horsehead

The red glow, normally visible behind the Horsehead nebula is severely reduced by the Canon’s filter, and appeared noisy. In addition, the colour was uneven with the poor flat field I had used. This one I obtained by shining a lamp onto a translucent film held over the scope’s aperture. I haven’t investigated whether the rainbow came from the flat or the star Alnitak (ζ Orionis), although from its position I strongly suspect it was from the starlight bouncing off the drawtube and interacting with my focal reducer lens elements. After applying a colour gradient removal, this beautiful optical effect was revealed with a wonderful colour balance and the dust clouds in the lower part stood out as a more 3D landscape from which the giant, black horse’s head protrudes. The horse has a red glow around the top of its head and a green glint reflecting off its dusty forehead. I differentially blurred the darker regions of the image more, to give a soft looking background, while still preserving the detail in the stars and glowing strands.

Cone Nebula

I found a bright star to follow, where I knew that a nebula lurked. So I set to work exposing my camera and guiding on the star at the top of the Christmas tree cluster in Monoceros the Unicorn (NGC 2264). A few 2-minute shots later (plus all the computer processing of course) I can reveal the image. The flat field image didn’t work too well again, so forgive the brownish blob around the centre. It’s hard to do these on a 20 inch Dobsonian. There are some colourful spikes on the cluster’s stars, some bluish nebulosity to the North and a pinkish nebula to the South. The latter is the Cone nebula. You can see the dark shadowy sector where some dust has got in the way of the nebula and blocked the light from the bright star, preventing the tenuous atomic hydrogen gas from fluorescing at its characteristic red and blue wavelengths.

Comet Fishing, by Malcolm Hartley

I cast my metaphorical rod into the waters of Monoceros, the Unicorn to find once again the huge comet Malcolm Hartley had discovered, swimming along the Milky Way. This comet has confined itself to the river of the night. I had spotted it near the double cluster in Perseus from a secret ultra rural site where I met with fellow astronomer friends, and now it had made its way through Perseus, Auriga and Gemini, heading for the double clusters of M46 and M47 in Puppis. Standing on an old Yellow Pages, I craned my neck up to the eyepiece to see a rather diffuse and dim glow. I snapped a quick sequence of 10 second shots, on which I could still see the movement when I flicked through them. Image taken 02:00UT 15/11/10.