Monday, 31 March 2008

Observing platform and second light

I built myself a little 'observing platform' in the garden, from old concrete blocks, yesterday. I dug a large square hole and laid the blocks in it, getting them as level as possible to provide a nice, stable platform for my Dob and it works well, getting its first use that evening.

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.