Friday, 22 January 2010

NGC 2683

There is no name for this galaxy as far as I know, but I discovered it on a sky ramble once with my 8" SCT just north of the constellation Cancer the crab. It was close to a little asterism in the shape of a kite. It sounds weird, but I thought of it as the crab-kite galaxy. I drew a lovely sketch of it, but now I have finally had the opportunity to take a piccy of it and even better, the picture shows a subtle texture detail. It is a lovely near edge-on galaxy, which always looks pleasing, with a subtle blue hint and other subtle splodges of colour towards the centre. There's even 2 little galaxies hiding near it! One of them being the 16.5 mag PGC 24945 (L). It's quite an overlooked galaxy because it's as bright as the brightest members of the Virgo cluster, but living isolated on the southern border of Lynx, it gets missed. It's surprisingly easy to find - just look for 'the kite' at the northern edge of Cancer, north of the star iota Cancri. It is 1ºN of sigma Cancri.

Eclipse to see out the decade

I tested out my new christmas present - a tripod with an old 400mm lens on my EOS. On new year's eve, I hopped outside my door and waited for the clouds to part, which they obligingly did to reveal a moon in mid partial eclipse. I spent quite some time squatting, craning my neck and shivering in the freezing cold. This picture was taken at 19:16 UT on 31/12/2009. I found the optimal ISO setting to be 400, because I closed the aperture to about f/18 for better focus and I stacked 4 short exposures. I enhanced the contrast to push the brightest spots to full brightness, and the moon starts to get lost in the umbra, so it appears fully black. This eclipse shows the range of brightnesses across the penumbra and shows the fuzziness of the shadow of the earth, caused by the half-degree angular size of the sun.

Wednesday, 20 January 2010

Pea in a haystack

Here's a strange one for you. A little green nebula right next to one of Messier's largest clusters, M34 in Perseus. It appears that some of the stars associated with the cluster have spilled on to my image of Abell 4 here, as it is dusted with some quite evenly-bright and evenly-spaced stars. When you've got access to a 20" scope, you should try out the Abell planetary nebulae if you want a challenge. I was blessed with a clear night so I used it wisely. PS Spot the galaxies.


Here is my picture of "the god of war", Mars, on the day after boxing day. It was taken the same night as the antennae pics below. An unusually still night and the planet was quite high in the sky. It turned out that it was only 12" across. I stacked 20 large jpegs on the Canon 350D at f/4.8 on the 20" (fl=2400mm) at ISO 100 and 1/800" exposures. I have blown up the pixels 4 x for comfortable viewing. I also took 20 raw-format pictures, converted them and stacked all 40 and got a slightly less pleasing result. I probably should have known how to use registax better and selected just the best few.

Friday, 15 January 2010

Lonely ball of stars

Having had that adventurous astronomical thought "where will I explore next?" I recalled a guest speaker mentioning the Intergalactic Wanderer. It is a lonely globular cluster, NGC 2419 in Lynx. It can be found by going a little way north of the star Castor, and it is just 10.4 magnitude and 6.2 arcminutes across, because it is more than a quarter of a million light years away in deep space. That means it is many times further away than any of those stars in the photo. The view of our galaxy from within the cluster would be pretty stunning but not like you'd imagine from sci-fi films. It would be something like our view of Andromeda but 10 times larger. This picture comes to you via the stacking and processing of 15 x 10 second exposures on the 20-inch at ISO 1600 and f/3.

V838 Monocerotis

V838 Mon is a star that went extremely bright for a few days in early 2002. Usually 16th magnitude, it reached 6.75 magnitude. At a distance of > 6 kpc this made it temporarily the brightest star in the Milky Way. Astronomers noticed a few days after it had faded that there was a brightening in the infrared. It turned out this was a light echo from the surrounding interstellar matter. You can google 'light echo' or 'V838 Mon' and you may well be familiar with the set of Hubble pictures, taken during successive months. Well, I thought I would try and hunt it down and see how it was doing. Not a lot. Never mind. That's mostly what happens in the universe.