Can good seeing be predicted?

Starkler (Geoff) · #1 02-12-2005, 07:23 PM

Yesterday was a warm day in Melbourne, and it stayed warm all night with little temperature variation. The jetstream map showed no blue bits anywhere near Melbourne. On the face of it, I thought this sounds like great conditions for planetary viewing but..... the seeing was absolutely horrible

It appears that the presence of jetstream will cause bad seeing, but the absence of it is no guarantee that the seeing will be good.

My question is, can good seeing be predicted? How ?

davidpretorius · #2 02-12-2005, 07:45 PM

anyone got a weather map from 6pm last night.

the seeing was 7/10 or 8/10 nearly ass good as snake valley.

lets compare pressure troughs!

davidpretorius · #3 02-12-2005, 08:08 PM

I had great seeing up to 12pm when i went to bed and then at 3.30am for saturn it was not quite as good, but very good none the less!

http://www.phys.unsw.edu.au/~map/wea...cir-precip.jpg

davidpretorius · #4 02-12-2005, 08:41 PM

i have noticed that the jetstream will follow the fronts a lot of the time.

i am thinking a big fat high pressure system sitting over you that is stable would be ideal, ie like the eye of a storm???

Dave47tuc (David) · #5 02-12-2005, 08:59 PM

Predict seeing

if only.
No matter the telescope if its bad seeing then no detail on anything.

My friend Julian who views the night sky more than anyone I know said
" This year has been the worst seeing I can remember"

I would like to know if good seeing can be predicted, but I doubt it.

But I can say it seems in the mornings seem to offer better seeing than evenings.

Other comments?

ballaratdragons (Ken) · #6 02-12-2005, 09:07 PM

This year the weather and seeing all over the whole of Australia is the worst I can ever remember.
I don't think predicting good seeing is reliable anyway as seeing can change in a matter of minutes anyhow. Transparency can be predicted! But that isn't always a good sign.

Starkler (Geoff) · #7 02-12-2005, 09:40 PM

Is it purely pot luck? What known weather conditions are known to produce good seeing?

ballaratdragons (Ken) · #8 02-12-2005, 09:50 PM

Cool, dry nights with no wind. Warm nights cause heat haze & sometimes dust. Though a dry windless night would leave Smog hovering near Big Cities.

fringe_dweller · #9 02-12-2005, 10:09 PM

your right Ken, tho have seen nights with good seeing but really windy - or cloudy - you have to laugh on those occasions eh

traditionally it is widely followed that when the isobars are widely spaced enough in an isobaric chart - most commonly with sloooow moving huge high pressure systems - that is the time - but the trailing western edge can be dodgy with an approaching front ect. influencing ahead of itself - but on rare occasions here it can be good with huge spaced slooooow lows too -
i agree about seeing for the last couple of years with these antarctic lows reaching up in to southern oz all thru summer - they used to get held down by the dominant, ants pace, highs - but the little puny wishy washy, tightly spaced, highs we have been getting for a few yeras are taking a belting at the hands of these roaring 40's type lows - they get pushed and bullied along and out of the way before they can get established - i remember a few huge high pressure sytems hanging around for what seemed weeks years ago?

[1ponders] (Paul) · #10 02-12-2005, 10:17 PM

While I don't know if seeing conditions can be predicted, I do firmly believe that the likelihood of good seeing is inversely proportional to the cost and/or desire to use your most recently purchased astronomy item. Ie: the higher the cost or the greater the desire the longer it will be before conditions stablize. That is of course after the clouds clear.

This is bought about by the generation of negative ions from excessive anxiety/twitchiness over how long before these "damn clouds disappear". In other words its the planets way of telling us to "Chill out. You'll get to use it when I'm good and ready to let you use it"

Mother nature is never cruel but she does have a certain implacability about her

fringe_dweller · #11 02-12-2005, 10:23 PM

in addition: the times i have seen the right isobaric conditions this year and last it has usually been very cloudy

and most probably full moon too hehe - not that matters tooo much with planets
i never realised about the jet streams influence - especially on mid latitude viewers - until i joined IIS - but it seems closely tied with what happens down here anyway (isobras match) - i now read that pesky jet stream also is heavily involved with creating high level cirrus on its southern? edge - which makes perfect sense of course
but i think possibly we get better transparency than our northern members sometimes due to that stream clearing muck away? hhhmmmm

fringe_dweller · #12 02-12-2005, 10:25 PM

Quote:

Originally Posted by [1ponders]

While I don't know if seeing conditions can be predicted, I do firmly believe that the likelihood of good seeing is inversely proportional to the cost and/or desire to use your most recently purchased astronomy item. Ie: the higher the cost or the greater the desire the longer it will be before conditions stablize. That is of course after the clouds clear.

This is bought about by the generation of negative ions from excessive anxiety/twitchiness over how long before these "damn clouds disappear". In other words its the planets way of telling us to "Chill out. You'll get to use it when I'm good and ready to let you use it"

Mother nature is never cruel but she does have a certain implacability about her

I love that theory!

fringe_dweller · #13 02-12-2005, 10:34 PM

i forgot to mention those strange little single line troughs are quite often in the mix these days too - especially with H pressure systems - we're all dooooommmed!

[1ponders] (Paul) · #14 02-12-2005, 10:37 PM

I don't know whether if its only theory kearn. I believe it's and unrecognized axiom of fundamental astronomical physics. I've seen it demonstrated without question quite a few times since I started sending myself bankrupt in the past year.

[1ponders] (Paul) · #15 02-12-2005, 10:45 PM

Back to a serious response now. With the massive urban expansion occuring around our coastal areas now I wonder how much effect the updraft of heated air created by all the new concrete, bitumen and steel roofs (and other causes) are having on the seeing, and whether this is going to be the longterm scheme of things. Is the poor seeing we are experience a result of low level turbulance in the atmosphere caused by human activities or is it a result of high level turbulance due to more prosaic weather activities.

fringe_dweller · #16 02-12-2005, 10:50 PM

I agree Paul - how much is low level micro climate stuff when you live in built up areas is something that crosses my mind a lot

ballaratdragons (Ken) · #17 02-12-2005, 10:53 PM

Quote:

Originally Posted by [1plunders

]With the massive urban expansion occuring around our coastal areas now

We are getting Light pollution from urban expansion!!! The new neighbours who built up the back (moved up from Melbourne) are leaving a giant floodlight on half the night every night!!!!

What is it with city-slickers and floodlights. Are they scared the killer kangaroos are going to get them???? Geez!

[1ponders] (Paul) · #18 02-12-2005, 10:58 PM

There is another effect of the urban sprawl that needs to be considered. When the ground is overed with vegetation, especially tall trees in forest situations, the boundary layer between the moving atmosphere and the ground is buffered by the swaying of the foliage and the general evenness of the treetops. In cities and built up areas that gentle buffering is replaced by hard edged rigid buildings, especially highrise, or buildings with upward sloping roofs, ie the burbs. From how I look at it this would have to increase turbulation in the lower atmosphere as the moving atmosphere traverses these static irregularities

[1ponders] (Paul) · #19 02-12-2005, 11:00 PM

c'mon guys, bit more subtle hey

fringe_dweller · #20 02-12-2005, 11:01 PM

their scared of the night sky Ken - it makes them feel helpless or tiny or something - it is the old mans dominion over everything disease - even the night sky!

PS np Mate - hehe i have only just discovered how to that with the text - i think my safari browser has trouble with the format sometimes?