Chris Curtis Web Site

The temperature stayed just above freezing all night (the first time for a fortnight) and there is a very slow thaw. When I woke I was aware of dripping from the eaves of the house – an amazing sound. Despite this, there is still snow everywhere and more is forecast. We are not used to anything like a real winter in this part of England so it is quite a shock – especially as the various authorities seem not to have coped at all.

ngc869, originally uploaded by ThinkingCamera.

This is part of the double star cluster in Perseus taken tonight (in the bitter cold) while there was thin high cloud and the moon was rising. The less than perfect conditions meant a lot of processing, which is why some of the stars are a little “clumpy”.

What you are looking at is a genuine collection of stars about 7000 light years away. The stars are very young – only 5 million years or so – and are still close together since they formed together in a great cloud of gas and have not yet had time to move fully apart. Most of the stars in the cluster are hot and appear blue but some have already used most of their gas and are expanding into red giant stars – very obviously different in colour to the blue stars.

This was made of 20, one-minute exposures, (Atik 16ic on 6-inch SCT) combined using “Astro Art” and further processed in Photoshop. The diffraction patterns on the brighter stars are courtesy of the “StarSpikesPro” plugin by Pro Digital.

The one-minute (rather than 30 second) exposures follow me updating the software on the mount for the telescope and then making a very careful polar alignment. The scope will keep an object in the field indefinitely now – visually, things stay where they started. This means that the telescope very accurately tracks the movement of the earth. However, photographically some one-minute exposures show movement while others show none at all. This is called “periodic error” and is because no mechanical system is perfect. The only answer is to guide the mount, using a camera and computer to immediately correct any movement while it is happening, and I will be experimenting with this over the next little while. I want to be able to do exposures lasting several minutes each to capture even dimmer and more subtle objects such as galaxies.

This is the second day of “close-down” following the heaviest snow for about 20 years in this part of England. Here in Horley we had about 6 – 10cm without much drifting, but just a few km North, on the North Downs, there was around 30cm (a foot) and some severe drifting which, coupled with the apparent inability of local government to respond and the lack of experience among local drivers, meant gridlock.
The snow was caused by easterly winds bringing very cold and moist air off the continent across a relatively warm North Sea and Channel. Heat and more moisture being pumped into the very cold air lead to a growth of shower clouds and showers, which fall as snow. Meteorologists call this “lake effect” snow from a similar phenomenon on the great lakes in North America.
Last night saw a severe frost (-6C) which froze the old snow surface hard and some new snow fell – very slippery conditions.
We now have some sun and a little thaw, so hopefully things can start returning to normal tomorrow.

The old year is ebbing away. The weather is the coldest we have had at New Year for as long as anyone can remember. The days are gloomy grey and misty and today it has just managed to climb above freezing for a few hours, but as the sun set 90 minutes ago it was already freezing again.
Here is a strong wish for peace and hope for everyone in 2009.