Saturday, 31 October 2009

Out of this world (literally)

This oddity is where astronomy and art mix.
I wonder if you know what this thing is?
I'll say no more than that this area
of sky intrigues me - what a cosmic field...

Hind's Variable Nebula

Here is one of the other less studied variable nebulae -
Hind's Variable Nebula. There are a lot of very, very faintly glowing clouds surrounding the whole lower half of the picture, but the clouds certainly aren't picked up in this image. So don't go scrutinising it too deeply - instead you can see the void in stars blocked out by dust. The star at the centre is T Tauri, the prototype of its own star class. To me it looks like the starlight is reflecting off a hidden, dark wall of dust to the right (of course there is no 'right' in space!). I thought I would slowly slew the big 20" scope to this nebula near the Hyades and get a few minutes worth of exposure in order to follow on from Gyulbudaghian's nebula (see earlier posts). Unfortunately it was quite low in the direction of a small town, which means it is impossible to cut through the light pollution and get a deep image. Still, I got my first look of it in the eyepiece.

Sunday, 18 October 2009

Another instance where a pair of tights comes in handy

Let me explain the title. At the observatory we were discussing how to get some real scientific measurements out of our telescope. It so happened that our expert former-professional astronomer and author member was there and he suggested that we could record the spectra of stars. For this purpose, we have a cardboard circular attachment with what looks like tights material streched over it, which velcros onto the front of the telescope. This is actually a clever but rudimentary diffraction grating that splits some of the light from stars into spectra that radiate out from them. We spent a while looking at bright stars and seeing rainbow starbursts all around them! However, we couldn't make out any colours in the outer spectra as they were just too dark. Our former-pro must have had unique eyes as he could see colour all the way out. At this point I got rather inspired, as I had once looked at a mysterious object called "Campbell's Hydrogen Star". It was an ordinary star to me at the time, except that it didn't disappear when I put a nebula filter in the eyepiece. Here is an image of that object (147"@ISO1600, f=2400mm f/4.8) and its spectrum which I have specially processed by cloning the image, rotating 180º & excluding anything that didn't match, thus highlighting only the spectrum of the object.

Campbell's star is a bright (9m) but very small (5") planetary nebula 2.5º north of the star Albireo, that went undiscovered until the invention of the spectroscope. It has a strong emission of hydrogen lines (see the red, blue, violet bands in the spectrum). Also there is some emission in the middle of the spectrum, presumably from the central star (11m). Maybe a messy picture, but pretty good for a pair of tights.

Friday, 9 October 2009

Northumberland Astro Soc.

Having travelled from Norfolk all the way to North of Newcastle, I got an extremely warm welcome by a friendly bunch of people at the Northumberland Astronomy Society (and free entry and a cup of coffee!). It was a Saturday, there was an entertaining open night talk by a Mr. Jannetta, to the point where it seemed like he had control of the heavens. It was a sharp and clear dusk over Hauxley, near Amble, and we had a nature reserve shed/hide as the club room. This was absolutely ideal as it pointed South across a prettty tidal wetland with a beautifully low horizon- the preferred direction for astronomers! But the best bit was the talk stopped at about 8:13 p.m. and we all gathered along the long window to watch the now superbright International Space Station sail slowly from right to left and "above" the planet Jupiter, which we could also see reflected in the water below. I bobbed down for people behind me to see and I rested my DSLR on the windowsill and got this 2 second snap. The only inconvenience was that I had to try to get back to Leeds by 11 p.m which meant no observing!