[VENT]
I want to measure the diameters of asteroids using asteroidal occultations. It's my small contribution to astronomy science. I'm not alone, there is a small band of dedicated chasers of very small shadows in Aust and NZ. Presently I'm limited to stars brighter than about 10.5. There are precious few such bright events and over the past many months none of them has occurred on a clear night - until last night when there were two.
Last night there was hope. Was.
I don't yet have an observatory so in the afternoon I set up in the back yard and reminded myself where all the leads and cables go. Check.
The first event was at 8.23. The goto mount was aligned by 7.20 and the Precises Goto landed the scope on a suitably bright star. Checking the finder charts confirmed that I was on target and ready to change the eyepeice for the camera. Now ..... about that small band of cloud to my south. Even on a clear night there tends to be a bit of low cloud over the steel works - they vent a lot of hot wet air. However during the alignment and goto the band had been moving north and now covered all of he southern sky. Luckily the star was in the northeast - I might yet be lucky. Fat (*&%(*) chance. At 8.10 the clouds covered the star. Not completely but far too thick to make reliable observations - sometimes the stars were visible, sometimes they all faded away for 10-20 seconds. So that was event 1 written off.
By 8.35 the sky was again completely clear!! That's right - the cloud arrived 10 minutes before the event and remained until 10 minutes afterwards. It remained clear until after midnight. [I spent much of that time learning to collimate the SCT that's supposed to replace the present setup. Can I go back to a newt, please
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Remember that second event? It was at 00.43 and in the northwest. Again I was on target in time but I was having trouble confirming the field I saw matched the chart. Luckily, there was only 1 appropriately bright star within the errors of the goto. No matter, it was all hypothetical. This time I didn't see the cloud start to roll in but I can confirm that it covered the target star at 00.38 - five minutes before the event. Why couldn't it wait just 5 &*&%#* minutes more?? You wouldn't want to have been in my backyard at 00.43. It wasn't pretty.
So all that remained was to pack it all away again under a leaden sky and trudge off to bed. I woke up with a headache.
When I look back at all the nights I've spent standing round looking at the clouds (I used to do grazing occultations) I really do wonder what I could have done with all that wasted time. Probably cure cancer and bring peace to the middle-east.
Anyone want to swap a shed load of astro gear for a shed load of decent red wine?? Or, even better, two shed loads of half decent red?
[\VENT]