Clear nights or not????

[scubaian]

Hi,

Over the last few weeks we've had a few clear nights (no clouds) in the evening time. I get the scope out and find that the objects i'm looking at are quite fuzzy or flickering. I know this is due to the quality of the air and movement of it but is there a site or a way in which the quality can be predicted, or easier, a site that tells me!

Tonight has been predicted to be clear for a couple of days and i wont know how clear everything will be until i look through the scope!

Slightly confused!

[JamesM]

From what you describe, my suggestion would be to make sure the scope has cooled down for long enough before observing as the effects you describe could be ascribed to thermals inside the tube. These thermals will effect your ability to obtain focus. I am of course assuming that you have a reflecting type of scope but as I don't know what size it is, I can't advise you on what amount of cool down time is needed. It's not just thermals in the tube, it's also the warm air that sits on top of a warm mirror when it's first brought outside into the cold night air.

If you are actually talking about 'clear seeing' where this is little air movement in the sky, then you are really only looking at a handful of nights per year and I'm not sure there are any notifications systems out there that provide such local information - I might be wrong though.

James

[scubaian]

I have a 80mm refractor (skywatcher startravel) and is generally cooled down for about half hour minimum before attempting to view.

[Doc]

You are thinking to much. It doesn't matter, we get so few clear nights, just grab them. Ok some might be a little dissappointing but it's better then cloud.

Just grab it when you can.

[Pete Presland]

this might help with the weather

Europe SAT24.com, Satellite Weather Europe, Weather Forecast, Rainfall, Clouds, Sun in Europe - Source: SAT24.com

these are whats up there at the moment observing wise

http://www.calsky.com/cs.cgi?obs=56207569695925

SkyandTelescope.com - This Week's Sky at a Glance

[Ad Astra]

The atmosphere settles down a bit if you wait an hour or two after sunset - that may help a bit.

I'm also wondering how close to the horizon you are viewing? Lower objects always have more trouble with seeing - you are just looking through much more air!

Last thought - are you viewing over a heat source? A roof, a blacktop parking area, etc? If so, a small shift in scope position can give you a major boost in image quality.

Hope that helps,

Dan

[swamp thing]

I don't think it would be possible to give out reports on seeing as it can be extremely locally affected.

It could be something local to where your observing from. Like boiler flu pipes, chimneys and the like.

Have a good look round while it's light then try to avoid observing near anything chucking heat out.

Hope this is some help

Regards Steve

[scubaian]

ok cheers. I have woods directly behind me (blocks anything below 30 degrees! (height not temperature)) so dont think its a heat source but will wait for a couple of hours after sunset to see if this settles.