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1201  General Category / Weather & Atmospherics / Re: Next Week's weather on: July 25, 2008, 09:01:06 pm
That's for the partial eclispe isn't it?
Yeah ... that's the important one. But it would be nice to get the odd transparent night now the twilight's less of a problem & the Moon is getting out of the way.
1202  General Category / Weather & Atmospherics / Re: What's This? on: July 24, 2008, 02:08:30 pm
Someone (leprechauns?) let off a very small atom bomb?

Seriously though we've got to look at the sky above. It's obviously unstable and humid. What I think has happened is that a bubble of nearly saturated air has found itself less dense than its surroundings, it's risen, some of the water vapour has condensed out (causing the mushroom shape) then the whole lot has got mixed up in the downdraft from the shower cloud above so it's evaporated away.

That "line cloud" above it looks really ominous, the sort of thing that sometimes spawns funnels!

1203  General Category / Weather & Atmospherics / Re: Thunderstorm Outlook - Wed July 23rd (low risk) on: July 23, 2008, 09:02:20 pm
It looks as well as feels thundery now, and my migraine is fully convinced.

View to the West from Portballintrae at 20:50 BST:

Canon 40D, 50mm, 1/50sec @ f/8, ISO 100
1204  General Category / Weather & Atmospherics / Re: Thunderstorm Outlook - Wed July 23rd (low risk) on: July 23, 2008, 03:14:08 pm
Getting thunderstorm type migraine Undecided

Also need to shut down PC to clean dust from fans, I'm getting temp alarms Angry

22C outside - no sun, and very humid!
1205  General Category / Weather & Atmospherics / Re: Where have all the clear skies gone? on: July 23, 2008, 01:57:26 pm
The moment a piece of astro equipment appears outdoors the clouds rush in and covers everything.
You might have something there. I think the Chinese are putting cloud magnets in all the kit they make!

On Sunday night I set up the WO FLT 110 about 8:30 pm to give it plenty of time to cool off & the cloud stayed away, except for a patch around Jupiter which is what I was trying to image with it. OK I did get a session but I'm sure I could have done better with less cloud.

Been out three times already today trying to get a look at the Sun, which keeps peeking between the clouds but hides as soon as my 8cm refractor (Chinese manufacture) gets outside. I'd mind less if it wasn't so bl*sted hot - if we're going to have Mediterranean temperatures, then at least we ought to have Mediterranean sunshine to go with it.

It's really frustrating, isn't it.
1206  General Category / Astronomy & Space / Re: Abstract ISS. on: July 22, 2008, 08:02:20 pm
Fancy doing a deeper exposure of Aquila John for signs of 6P/d'Arrest?
Nearly had a go on 20/21st - did have a look & think but not quite sure I could just see something with 8" LX90 x77. The moonlight was a problem though.

The best results I've had for photographing brightish diffuse comets have been from using a 300mm f/4 lens either piggybacked on the scope or on an Astrotrac - stacking about a dozen 30 sec exposures using DSS is very effective in increasing the signal-to-noise ratio, and using a DSLR means that the comet shows up as a distinctive greenish blob, quite different from any nebulae which happen to be in the shot. A light pollution filter helps knock down interference from street lights etc. but does not suppress moonlight.
1207  General Category / Astronomy & Space / Re: Jul.20/21 observation on: July 22, 2008, 01:09:26 pm
It is really something happening if you hadn't seen the W1 Boattini with your 8.5" F/7 refractor.
Hmmm, I've noticed that diffuse comets sometimes show up better in a finder, or binoculars, than they do in a medium to large scope - the contrast gradient is steeper. I found Holmes was visible in binoculars for about three months after the last time I saw it in a scope - the integrated magnitude was 4 to 5 at the time but there was no way a scope would show it!

C2007/W1 Boattini certainly was diffuse before perihelion - I'm not giving up until the next Moon period - the dark period between New Moon and waxing gibbous is perhaps the best opportunity - approx. Aug 1-10.
1208  General Category / Astronomy & Space / Re: Multiple ISS Transits - July 20/21st on: July 22, 2008, 08:49:03 am
This was the coldest night for months with a slight air frost. The bright Moon made the land and sky look like a Autumn night. It felt like it to.
Eeek! Minimum here on the North Coast Jul 20/21 was 10.3C despite largely clear sky!

However I do agree about "autumn" - once Arcturus is dropping to the horizon and Aldebaran is seen rising in the East, the season does seem to have changed. Not long now until the first sight of Orion looming above the SE horizon.
1209  General Category / Weather & Atmospherics / Re: Low Clouds, Showers & Bows From The Road on: July 21, 2008, 01:41:08 pm
Must be the mountains!

Here on the North Coast, quite a nice day yesterday with lots of sun and occasional thick stratocumulus but no showers. Cirrostratus this morning (most of a 22 deg solar halo visible aound 1015 BST) now thickened into altostratus. Still, got a reasonable night's observing last night - just a suspicion of NLC in the NE in morning twilight.
1210  General Category / Weather & Atmospherics / Re: Where have all the clear skies gone? on: July 21, 2008, 01:36:50 pm
Unfortunate to hear this guys. That's strange because I was clear here all night except for the occasional shower and so was John. There were occasions when it was overcast but within 10 min's it was as clear and crisp as a Winter's night. Seen two ISS passes but no NLCs where present along the skyline. Maybe clear tonight going by the forecast.
Hmmm ... the weather here does often seem to be local, and I've found the regional forecast for Western Scotland is usually more accurate than that for Norther Ireland. Well I can see the Hebrides (Islay) from my window, given normal atmospheric clarity, it's only half as far as it is to Belfast so perhaps that's not too surprising.

Some scientists who are not main-stream fully believe that global warming now could trigger a rapid cooling in the not to distant future. The increasing presence of NLCs are thought by some to be a sign of global warming to. No matter if the climate warms or cools humans will adapt, like they have been doing for millions of years.  Smiley
The Gulf Stream circulation does seem to have slowed down a bit, whether that is a consequence or a cause of changes in the climate is debatable. If it does "turn off" then the climate here will indeed change, with long very cold winters.

We humans haven't been around for all that long - at most 150,000 years for Homo sapiens - and adaptation takes time. Whether our attempts to use technology to modify the climate will be stabilizing or destabilizing, or completely ineffective, is very much open to debate. The Earth is not at risk, and neither is life on Earth, but our way of life and the dominance of large mammals is, I would think, very much in doubt if warming of the order of 5C in a century occurs.

IMVHO our best bet is to take measures to reduce our population to a sustainable level - much lower than at present - a "greener" lifestyle will do no good at all if we carry on overrunning the planet, exploiting resources like land for our own short-term benefit.
1211  General Category / Weather & Atmospherics / Where have all the clear skies gone? on: July 20, 2008, 07:19:18 am
I thought I was going to get a clear night last night - at 2300 BST the sky was pretty much clear. At 2320 I'd finished lugging the LX90 out & had aligned it, noticed some thin cloud appearing high in the NE. Not drifting in, just forming. By 2330 the whole sky was pretty much solid stratocumulus; it carried on thickening until at least 0130 when I gave up.

This has happened several times in the last few weeks. In fact I've had exactly four nights in the last month (since Jun 20) when it's been possible to do any observing at all; on one of those nights I got only a few minutes and another one was pretty awful with lots of drifting cloud.

So - where have all the clear skies gone?
1212  General Category / Weather & Atmospherics / Re: Ballycastle on: July 17, 2008, 11:11:25 pm
I suspect the curved formation could be some sort of accessory cloud under the cumulus perhaps drawn into a curve by a local area of vorticity or convergence zone but I'm blindly guessing.

Bit of a tricky one. Brian, any ideas?.
Not really, the only phenomena I've seen like that are shock waves ... you didn't hear a bang, did you? (Maybe up to a minute later)

The association with the position of the Sun appears to be "accidental" but it's possible that the effect would have been invisible if it occurred somewhere else in the sky i.e. it needed the Sun to be close by to make the "wall" visible.

It looks as though the effect is either disrupting the higher thin broken layer or is a seperate thin layer underneath it as the structure of the altocumulus (?) layer is fuzzed out in the vicinity. The presence of the iridescence suggests that the water droplets in the cloud are very uniform in size, which would suggest that the cloud is just forming. That, I think, is a clue to one possible cause - suppose a rising warm dry air bubble bursts through a thin layer of air which is saturated vapour without droplets, forcing it to rise & cooling it enough to start condensing, whilst the bubble of warm air passes through (and eventually makes its own cumulus head). But this is theoretical, as I say I've never seen it like this - the dimensions look about right for a typical weak thermal, though. What usually happens is that the warm air bubble is more humid than the surrounding air (because it's come from a warmer level, and has picked up more moisture) so it saturates & starts to condense rather than the air it drags up with it.

Really I don't know.
1213  General Category / Weather & Atmospherics / Re: Thunderstorm Outlook - Fri 18th on: July 17, 2008, 09:10:58 pm
Nah, won't happen. I get migraine when it's going to thunder.
1214  General Category / Astronomy & Space / Re: Solar Eclipse on: July 17, 2008, 07:18:14 pm
Parameters as follows:

Belfast 08:23 - 10:04, mid 09:12 19.4%
Glasgow, 08:23 - 10:09, mid 09:15 23.1%
Edinburgh, 08:24 - 10:11, mid 09:16 23.4%
Manchester, 08:27 - 10:06, mid 09:16 16.8%

(Times in GMT/UTC, max percentage by area)

Will probably observe from Portballintrae car park with 80mm refractor (objective filter), Coronado Ha PST & filtered binoculars.
1215  General Category / Astronomy & Space / Re: C/2006 OF2 Broughton on: July 16, 2008, 07:30:09 pm
We are long over due a bright comet in the northern hemisphere.
Forgotten Holmes already?  Shocked
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