Thursday, 31 December 2009

in the wee hours

I got an early look at the dark, spring sky the other night. I went down to the observatory at 2am. This was the only non-moonlit clear free period I have had where it has been safe to travel, i.e. above 0ºC, just. I got the scope ready well before the moon set at 3am. It is a better time to observe, because a few people will actually turn their lights off and headlights become very scarce. Although there were a few flashes of lightning and a little mistiness to the upper atmosphere it was pretty still air and Mars looked surprisingly detailed, with 2 surface features visible and a lighter polar region. When I looked it up, the diameter was only 12"! However, as per usual, the scope did not track well enough for photography. I was getting nice 1/800" ISO 100 pics of Mars, but when it came to long exposures the wobble looked terrible. I had a quiet* battle with the tracking for a couple of hours until during an ascending slew, the declination motor decided to scream and stall on me (* the motors actually make a loud, quirky, metallic noise while tracking). After a gentle push, I found that a bit of weight on the scope helped.

By this time, the constellations Crater and Corvus (the cup and the crow) were up in the south. Scanning my cerebral databases I headed towards the Antennae galaxies. So here is my picture. Taken around 5 am, about 24 reasonably tracked pics of the Antennae galaxies (NGC 4038 and NGC 4039), at 30" exposure, ISO 1600, f/3(ish), stacked, processed and tweaked. It's a fascinating object and the word 'object' is a bit of an understatement. The faint 'antennae' are stars flung out by the combined gravitational interaction of the merging galaxies' stars. In the centre of the galaxies there are bright patches that are zones of star birth triggered by gravitational shockwaves in the material, brought about by the galactic collision. To reveal the antennae was well worth putting up with the freezing wind blowing on my face for 5 hours.

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