Monday, 31 March 2008
The Dob got it's second light (as it were) yesterday evening. I had the best views I have ever had of the Owl Nebula (M97) in Ursa Major; it had a definite greenish tinge to it and, for the first time, I saw the 'eyes' - two dark holes in the nebula - that give this interesting PN its nickname, although these were only really evident when I put an OIII filter into the eyepiece.
It wasn't a deep sky night, due to the high cloud - there seemed to be a 'cover' of very high thin cloud - but the views were not too bad of the brightest objects although the scope needs collimating, as while low magnifications are ok, the view through higher mags is out of focus, with a kind of shift to one side (i.e. one side of a star or planet is good, the other awful). This is due purely to collimation issues, so once I have sorted that out, the views will improve. I have bought a laser collimator for this purpose. Collimation isn't hard, just a bit of a pain in the arse to have to do.
Increasingly bad conditions and the need to have to get up early for work meant I had to pack up at around 9.30 pm. Nearly as irritating (although not a reason for packing up in itself) was a light aircraft that kept flying round in circles - funnily enough, and I have lived under Heathrow's flight path in the past, I never find the noise of big jets anywhere near as annoying as the buzzing drone of a light propeller aircraft.
Sunday, 23 March 2008
I have sent off for a laser collimator from Telescope House, a cheapish one at £34.99, so hopefully that will make collimating the scope easier and quicker. This is the first large Dob I've owned so keeping the mirrors aligned properly will be more of an issue.
Here are a few photos:
Looking down the tube:
It was made with a 2-inch focusser but this can be adapted for 1 1/4-inch eyepieces, such as all mine are until I replace one or two with 2-inch versions (2-inch is the upper picture, 1 1/4-inch is the lower pic):
I am hoping for a clear night tonight so I can see how well (or not!) it works. Richard said that it focusses, but a bit further along the focus (it racks almost right in) than he'd like, so if that is a problem with some eyepieces, the mirror would need to be raised.
Tuesday, 18 March 2008
Saturday, 8 March 2008
Huts teetering on the edge.
View of the camp site, looking north
View looking east-south-east, back towards Chale.
VAS member Bill Johnston's Celestron C14
As it looked like it was going to be clear, I drove home, picked up my stuff and drove back; Radio Solent's weather forecast was excellent, promising clear skies and a frost. When I got back to Brighstone, Owen Brazell was setting up his gorgeous Obsession 20" Dobsonian and others were getting their gear ready as well. Dusk was falling and it was looking reasonably good.
Unfortunately this state of affairs did not last long. A threatening bank of cloud in the north-west decided to make its presence felt and soon blanketed the sky. Soon all observing was being done through sucker holes that kept opening and closing aound Orion, Canis Major and Monoceros. I managed to get a look at NGC 2359, known as 'Thor's Helmet' in Canis Major, through Owen's Obsession. This is a comparatively bright nebula and, visually, looks more like a referee's whistle more than a Viking helmet.
Of course, the scopes were more engaged looking at the lollipops, because the conditions were no good for serious deep sky observing and, naturally, Orion's famous M42, the Great Nebula, was a main feature. This showed superb detail though a Meade 10" and even more so through the 20" with a UHC filter attached, with filaments and extended nebulosity. You could easily see the structure that 18th and 19th century observers such as the Herschels and Lord Rosse drew and described, with the hatched structure very evident. I'd never seen this structure visually and had always thought the old drawings a little fanciful - but not any more!
Soon the sky was a complete cloud out and, as I'd had to be up that morning at stupid-o'clock to go to work, I packed up and drove home at 9pm.
It was a good fun evening and, despite the limited observing, was full of conversation and happy faces. I hope our little Isle of Wight Star Party grows and grows. It has a bright future, despite the iffy weather.
More to follow...