Highest wind speed for observing.

[BilliGoatsGruff (Billi)]

What would people recommend as the highest possible wind speed for viewing. It's quite breezy outside (roughly 17km/h) and I'm wondering if it's worth bringing my gear back inside, or having a go anyway.

[ZeroID (Brent)]

Depends on your gear and your location. Small scope, big mount, you might get away with it, big scope, forget it. That's just one advantage with the Observatory, my gear is just below the wind line mostly and those windy nights quite often have low humidity and better seeing.

[BilliGoatsGruff (Billi)]

I had a look at Jupiter earlier and there was a lot of air movement. Do the wind conditions at ground level affect the jet streams (not sure what they're called) because it was quite calm then.

[SkyWatch (Dean)]

Originally Posted by BilliGoatsGruff

I had a look at Jupiter earlier and there was a lot of air movement. Do the wind conditions at ground level affect the jet streams (not sure what they're called) because it was quite calm then.

Hi Billi,

There are a lot of things that can effect seeing. The jet stream is one (this is high altitude stuff!), as well as invisible moisture in the air (could be at any level), local turbulence due to hot air rising from the ground or nearby buildings, air-conditioners, chimneys etc., air currents in your scope due to different temperature of the mirror and the ambient air...

Jupiter would also have been reasonably low when you looked: and the more air you are looking through then the worse the seeing can be. I would check Jupiter now if I were you, having allowed it to rise a bit more and your scope to cool to ambient temperature. ("Harold" would normally take 30 minutes or so for his mirror to reach outside temperature.)

Low speed wind around your observing site usually won't cause too many seeing problems, unless it is strong enough to buffet and shake your scope. Harold should be reasonably stable and I would have thought he could cope with your 17km/h breeze. There is an easy way to find out- and because he is so portable it should only take you a minute or so to set him up and check.

Happy observing! I am jealous of your dark sky, and I miss the Riverland!

All the best,

Dean

[BilliGoatsGruff (Billi)]

Originally Posted by SkyWatch

Hi Billi,

There are a lot of things that can effect seeing. The jet stream is one (this is high altitude stuff!), as well as invisible moisture in the air (could be at any level), local turbulence due to hot air rising from the ground or nearby buildings, air-conditioners, chimneys etc., air currents in your scope due to different temperature of the mirror and the ambient air...

Jupiter would also have been reasonably low when you looked: and the more air you are looking through then the worse the seeing can be. I would check Jupiter now if I were you, having allowed it to rise a bit more and your scope to cool to ambient temperature. ("Harold" would normally take 30 minutes or so for his mirror to reach outside temperature.)

Low speed wind around your observing site usually won't cause too many seeing problems, unless it is strong enough to buffet and shake your scope. Harold should be reasonably stable and I would have thought he could cope with your 17km/h breeze. There is an easy way to find out- and because he is so portable it should only take you a minute or so to set him up and check.

Happy observing! I am jealous of your dark sky, and I miss the Riverland!

All the best,

Dean

Thanks Dean

I set up on the back table before dusk so that the mirrors could cool to the right temperature. The wind has set in now and it's pretty chilly so I'm going to give it a miss.

I've had a lot of people comment on our exceptionally dark skies. To be honest, I thought they were like that in any country location. I guess it's a bit of newbie naivete

[AEAJR (Ed)]

When it gets windy the wind can cause vibrtions of my 8" Dobsonian or my 80mm short tube refractor. Is that enough to send me in? Depends. If it is an occasional gust, no. If it is constantly blowning the scope around then I have had enough.

I probably would not head out in more than 10 mph breeze as I just don't find it comfortable this time of year in New York. In the hot summer it might be very welcome.