Why Melbourne

[HCR32 (Peter)]

Hi Guys

So many times I have heard people on iis suggest that Melbournes seeing condition are poor most of the time and that when average to good seeing comes its a once in a life time oppertunity to get out there and get your planetary images. I just want to know why that is or is it just coincidental that I have read bad write ups?

Thanks

[Alchemy (Clive)]

Seeing is poor if it's cloudy all the time.........

I hadn't thought it was overly poor, not obviously as good as some prime sites like Hawaii, canary islands or atacama desert. It may be the jet stream winds are poor over us ( earth has bands of winds somewhat similar to Jupiter in hat you have varying trade winds etc and may just be unfavorable) plus the majority of winds in Melbourne are actually northerlies which come over the continent and then over the great divide which would cause low level turbulence.

I'm sure some of the planetary imagers could give a more accurate analysis.

[pgc hunter]

While Melbourne won't win any awards for best observation site on Earth, seeing here isn't that crap, well it's pretty average, but not terrible. Most nights planets look decent at 200x and I can use 300x for DSO observing more often than not. Infact, some of the poor seeing I get might be the result of my local surroundings as I observe from a concrete patio wedged inbetween my house, a water heater and the fence.


Summer seems to be best, winter worst when it comes to seeing here, don't know why, but those are my observations. The real problem here is not seeing, its the freakin permanent cloud cover

[HCR32 (Peter)]

Well with seeing here being so average at times I would say that aperture would have to be limited somewhat. What. Would be the point of having say a 14inch when your seeing is bad?

[rmcconachy]

I agree with Sab (pgc hunter) that summer (I'd include early autumn too) seems to offer more nights with decent seeing than winter/spring. Many of the nights offering the best seeing seem to be still, warm and slightly hazy (lousy transparency but good seeing). The nights offering the best transparency are often the opposite, e.g., shortly after big cold/rain fronts pass through you sometimes get great transparency but the stars are twinkling madly.

Even on nights of poor seeing there are usually small periods when the seeing momentarily improves and more details can be glimpsed. Also, larger apertures collect more light which improves the colour saturation of the image making some features easier to distinguish.