The difference between 'Seeing' and 'Transparency' ?

[bus_ter]

Am I right in saying..

Transparency is how visibly clear the viewing conditions are. A misty night would be one of extremely poor transparency. Transparency cam be predicted from a weather forecast from the visibility rating. i.e 'excellent' would be ideal, and 'good' would be average?

Seeing is invisible and is an effect of the movement of the atmosphere at high levels. When the 'gulf stream' is forecasted to be passing over the UK we can expect poor seeing?

[LukeSkywatcher]

You seem to have it correct. I am not sure about the gulf stream though.

[jimmyjamjoejoe]

Correctamundo. Transparency is a measure of moisture/dust in the air, ie visual clarity.

Seeing is a measure of steadiness (or turbulance, depending how pessimistic you are). Bad seeing is what causes stars to twinkle, and the moon/planets to ripple/boil. It is basically like the heat waves you see above a road on a hot sunny day, just on a much larger scale.

Seeing can sometimes be less obvious than the boiling/rippling effect though. I've had nights with very steady images that appear to be in good seeing, but they just turn mushy at high mags (mushy but steady). I'm guessing this is still an effect of seeing, just on a much fine scale.

[brantuk]

Seeing can be also be affected by high thin cloud which isn't visible till you magnify it, and light pollution from Earth and the moon bouncing off the atmosphere and washing out deeper objects. Dunno if those contibute to transparency as well - but I do know that both need to be good for a sucessful session.

[ollypenrice]

I hope the Gulf Stream will be good enough to refrain from passing over our heads since it's an ocean current! Otherwise you're right. Oddly enough poor trasparency and good seeing often go together so a bit of thin haze can often mean that excellent planetary observing is possible.

Olly

[JamesF]

Jet Stream rather than Gulf Stream, perhaps?

James

[LukeSkywatcher]

Jet Stream rather than Gulf Stream, perhaps?

James

Well spotted.

[rory]

or soda stream ..... ( ok im leaving )

[dph1nm]

and is an effect of the movement of the atmosphere at high levels.

Seeing can actually be extremely localised e.g. heat given off by houses

NigelM