Monday, 7 October 2013

A HUGE planetary nebula

The Helix Nebula, a large death shroud of a star, floats across the Southern sky in October and November and never climbs higher than about 23 degrees altitude. The width in our sky (as it is quite close) is around half the size of the moon but it is very much fainter and usually buried in the murky low atmosphere. I used the large aperture of the 20 inch telescope and the society's Atik 383L camera to capture it. I got 6 minutes through each of 5 filters: Red, Green, Blue, Ultra High Contrast, and Luminance (all white light). The scope is due a drive upgrade soon but it was working more or less satisfactorily last night on this object. There were a few jitters, but no guiding was required, now that the pointing model has been reset. This planetary nebula has thrown off another fainter wisp of gas that you can make out to the lower left. The centre is glowing mainly from the emission of doubly ionised oxygen atoms and the outer part, hydrogen atoms. It was a splendid starry night, with transparent sky right down to the horizon initially, before a little mist started to form and was wonderful to look up at the Milky Way while I waited for the camera to do its thing.

Thursday, 3 October 2013

Welsh skies

I was expecting good things if clear in Wales, and I was rather disappointed by the Brecon Beacons Dark Sky park. It had a large amount of glow from the South/SouthEast, and this was viewing it from the North of the park in Hay-on-Wye. The skies were very transparent and I could see stuff well overhead but the low light pollution was pretty bad. Also, the campsite owner had put up badly directed high-pressure sodium streetlights all over a beautiful little field. Hay, despite being a small place also had a few overly large lights, which affected the whole valley's look at night. There is of course the problem of clouds in the western part of Britain, let alone rain, so the view from the valleys was mist. However, when I got to the Gower peninsula I was pleasantly surprised to see all of the main Sagittarius asterism and when I got to the cliff top the Milky Way was touching the sea! The coastal light pollution to the left and right was horrendous but all there was to the south were a few distant lights on the coast of North Devon. I got the Canon on a little tripod and snapped a sequence of 30s shots, which I stacked a bunch of. In the picture here, taken after astronomical twilight, I have replaced the horizon and subtracted the large scale background features to bring out the details.

More Wales shots

Here's the view when I returned to the tent on the cliff top at Three Cliffs Bay, The Gower, Wales (30 second shot).
A view I first got after rushing to grab my camera from the car. This shows the star Kaus Australis in Sagittarius - a rare sight from this country.
A 90 second shot (detrailed roughly in Paint Shop Pro)

View from Hay-on-Wye

Some views of the sky from the North-West valley slide in Hay-on-Wye. Looking SSW (toward the Brecon Beacons dark sky park), SSE and ESE (into England). The levels of light pollution near the horizon can be seen. The bright campsite being typical of peoples unawareness of the dark sky status. I tried driving further up into the hills where it was dark indeed, but the foliage, hills and cloud spoilt my assessment of the sky.