Andrew's Astronomy Blog

Living within a spiral galaxy gives us the chance to get an up close view of the dust clouds that fill the inter-stellar space in the spiral arms. If it wasn’t for this dust obscuring the starlight from millions of stars then our night sky would look very different.

This image is a wide-field view of the area around Cygnus. Six exposures of 3 minutes each at ISO 800 and f/3.5 with my Sigma 10-20mm zoom.

One of the main attractions of La Palma was it’s views of the Milky Way. It’s southerly latitude opens up views of our galaxy’s centre that just aren’t possible from the UK. This picture is a mosaic of two images taken with the Sigma 10-20mm set at 10mm on my Canon 350D. Each image is a stack of three 3 minute exposures at ISO 800 and f/3.5.

Cygnus and Lyra are at the top of the picture, with Scorpius and Sagittarius at the bottom.

Well, I needn’t have worried about the clouds. On the West side of the island I had six clear nights out of six (Dan had seven but I was down on the coast that night under the inversion layer!). Six solid nights of getting to bed at 3 & 4 in the morning, getting up at 9 and wandering up volcanoes. At least I got the odd nap during the afternoons.

All of this didn’t leave any time for image processing or blogging so I have a fair backlog to get through. I’ve started with the image I first posted on the Breckland Astro forum. I’ve now removed the colour cast and some of the light pollution gradient although this wasn’t entirely successful.

It’s not everyday that a supernova explodes in a nearby galaxy, especially not as close as M51 (27 million light years). The last one in this particular galaxy was in 2005. Of particular interest this time is that M51 is one of the most imaged objects in the night sky so there’s a lot of possibility for examining it’s evolution before it’s official discovery.

So, here’s Dan & my picture from last night with the supernova marked:

One of the surprising things about the night sky is the number of galaxies out there that can be photographed with a humble 70mm refractor and Canon DSLR camera. With my last few outings concentrating on Ursa Major for this clear night I decided upon the Virgo cluster and the Markarian Chain.

The Virgo galaxy cluster contains upwards of 1200 galaxies and it’s centre is 53 million light years away. Together with the Local Group it forms a small part of the Local or Virgo Supercluster.

The Markarian Chain is named after the astrophysicist who first noticed their common motion in the 1970s.

Imaging these galaxies was surprisingly difficult after the large spirals in Ursa Major. Being further away, they’re smaller and fainter and there’s a lack of bright stars in the near vicinity which makes locating them harder. Fainter means that more exposure is required to bring them up out of the background noise. Being close to the Celestial Equator also means that the polar alignment is rather more critical than I’ve become used to. While I did make a correction to the mount after the first couple of images it still required more refinement.

For these images I put the focal reducing William Optics field flattener on the camera and to compensate for the increased photographic speed of this combination reduced the exposure time to 4 minutes per frame. The focal length is reduced to 336mm. I’m not entirely happy with how this focal reducer works just yet; some more experimentation is required. It may be that it isn’t an ideal combination with this telescope.

I’m not going to even try and label all the galaxies in this image.

Telescope: WO 70mm Zenithstar with FF3
Camera: Canon 350D
Frames: 18x 240 second

After my last picture of M101 I was anxious to see what a little more exposure would do for the image. I got my chance at the beginning of April with a beautiful clear night and exposed 15x 5 minute frames of this area. Leaving the camera on ISO 800 was probably a mistake as it causes the brighter stars to lose colour. In future, I will probably stick to ISO 400 for this length of exposure.

The bright smudge to the right of M101 is NGC 5474, a gravitationally bound near neighbour of M101 and a disrupted dwarf spiral galaxy. The core is offset by it’s interaction with the larger galaxy.