So, when does it actually get dark?!

[mhc]

OK, daft answers aside, what causes the large variations in the amount of light at night in a given location?

I'm in north Manchester (UK). It is night time (11pm). There is no moon. Yet tonight I couldn't even see Polaris. Is it some sort of very high altitude mist (no clouds apparent from my garden)?

What am I missing (other than sufficient IQ points)?

[Chubster]

Think it is to do with the recent hot weather and the amount of poo up there......Need a good day of rain to flush it all away. Thats my technical opinion anyway :D

Chub

[GazOC]

I agree Chubs, a decent downpour will sort things out, even an hour or so is usually enough. I love that smelll as well.....

[richmace]

It's been misty where I live all week. last night I could barely see Saturn, so it must have been REALLY bad

[Whippy]

Same round this neck of the woods.

I believe it's because during the day the heat from the Sun 'sucks' moisture from the ground up into the air making clouds. When the sun sets and everything begins to cool down, the moisture cycle slows down and it 'sits' in the air or clings onto anything that's cooler (like your astro gear!). With this moisture in the sky you get a double hit with bad seeing but with more light being reflected up into the sky from things like streetlights. A good downpour would bring most of this moisture back down and freshen things up. The only problem with this is you're going to get a wet backside if you're aligning your mount with a polarscope!

I had trouble even seeing Polaris the last couple of nights because the skyglow was so bad! Basically if the weather is predicting mist early next morning, be prepared for cack seeing.

[Kain]

Warm air rises, so in weather like this it carries pollutants and dust into the atmosphere (known as air pollution)

What we really need is a good thunderstorm. The lightning vapourises the dust and the hail at the top of the CB flushes away the pollutants, basically the cell eats all the Rubbish in the air.

A rain shower will clear it somewhat, but a thunderstorm will make a better job of it.

Kain

[Kaptain Klevtsov]

So where do I buy a thunderstorm?

Captain Chaos

[Whippy]

At the Thunderstorm shop. Obviously.

[themos]

A vortex ring generator is what you want.

[Vega]

Just looked today and I can see the hills from my workplace as clear as a bell. First time for 2 weeks! Maybe this means all that 'poo' has gone. Just need the clouds go hang somewhere else.

Matt

[dogfish]

Hi Matt

Not sure where you are, but here in Scotland the air cleared up a lot last night. I was setting up at about 8.30pm when a bank of cloud rolled through from the NW. Following the cloud was colder and clearer air. I was outside until about midnight (freezing by the time I went in) and had a great evening, even in my light polluted back garden. Hope it's headed down south so there's more fab piccies posted by the imagers tomorrow.

Cheers, Martin

[Vega]

I'm in the other corner of the UK... Somerset. Was clouded out last night. Today the clouds have gone, looking forward to tonight. Want to have a gander at the Leo triplet. I'm hoping my humble 120mm frac is up to the job. Also wanna gander at M81/82 but is prooving to be a pain due to the refractor 'zenith blind spot'

Matt