Please Explain.

§AB · #1 22-05-2008, 07:46 PM

Okay, so the jetstream is 500 miles away, there's a thumpin big high pressure cell parked right over Vic and the air is cold and still. Upper layers appear to be rather stable aswell. Tasmania, Sydney and Adelaide have been getting awesome seeing. So why is it that right now I am experiencing among my top 10 crappiest seeing nights ever in Melboune???

Starkler (Geoff) · #2 22-05-2008, 08:57 PM

Wasnt that bad an hour or so ago when I checked out saturn

Terry B · #3 22-05-2008, 09:01 PM

What seeing?
All I have is mist.

Bassnut (Fred) · #4 22-05-2008, 09:02 PM

Whaa?,......... so,,, why would anyone live in ......... Melbourne ?

iceman (Mike) · #5 22-05-2008, 09:12 PM

Maybe your scope wasn't cool enough?

Starkler (Geoff) · #6 22-05-2008, 09:26 PM

Quote:

Originally Posted by Bassnut

Whaa?,......... so,,, why would anyone live in ......... Melbourne ?

Not for astronomy thats for sure.

§AB · #7 22-05-2008, 09:45 PM

Quote:

Originally Posted by iceman

Maybe your scope wasn't cool enough?

I do leave it to cool for atleast 1.5 hours with the fan before every session.

Quote:

Originally Posted by Starkler

Not for astronomy thats for sure.

Melbourne: Where seeing is crap even in the best case scenario. Just another wonderful trait of our gorgeously cloudy climate. And it happens everytime.

Jeff · #8 22-05-2008, 09:48 PM

Fog is forecast for Melb tonight ... seems high humidity (moisture from the recent rain I guess) plus lack of wind is causing mist/fog.

Frost is also forecast for northern Vic over the next few mornings.

I gave up at about 8pm. Hopefully tomorrow night will be better.

§AB · #9 22-05-2008, 09:50 PM

I can see a bit of cloud around but is really insignificant. I take those fog forecasts with a grain of salt coz usually the most we'll get is some light mist. If we do get actual fog it usually establishes not long before dawn.

Karlsson · #10 22-05-2008, 10:30 PM

Is the seeing bad in all directions?

From my backyard the seeing depends on which way I point the scope - to the N is a national park, usually quite stable, but to the E is residential properties, and in wintertime I can see the heat rising from the roofs...

And the West is the worst - my own roof

Starkler (Geoff) · #11 23-05-2008, 01:36 AM

Just came inside from looking at Jupiter with the refractor.
The seeing was about 'average' for Melbourne and this time of night.

Gave the 5mm HD ortho I bought from Dave a run and it works pretty well if I hold my eye back a little, which is no drama with a driven scope. Less scatter than the bo/tmb for sure, but no difference in sharpness detectable in average seeing.

§AB · #12 23-05-2008, 04:28 AM

I'm about to go out, star twinkle is far steadier than the ridiculous terror last night. If all I get is a blurry blob (as has been the case every single time so far this year) then yer melbourne's climate sucks beyond all reprehension.

davidpretorius · #13 23-05-2008, 05:49 AM

Dont forget the heat rising from structures, falling temperatues that mean your fan cant keep the mirror at ambient.

From Berwick is in the city, so there are lots of things around you that radiate heat.

Remember that .5 to 1 degree difference in ambient and mirror is enough to distort things.......so imagine what black tarmac or warm house bricks are doing as they cool slowly early on in the night.

xelasnave · #14 23-05-2008, 06:01 AM

I was born in Melbourne so the place is cursed obviously
alex

§AB · #15 23-05-2008, 06:25 AM

Well it was a bust. No surprises I guess. What a **** climate.

Dave47tuc (David) · #16 23-05-2008, 12:40 PM

Quote:

Originally Posted by Starkler

Just came inside from looking at Jupiter with the refractor.
The seeing was about 'average' for Melbourne and this time of night.

Gave the 5mm HD ortho I bought from Dave a run and it works pretty well if I hold my eye back a little, which is no drama with a driven scope. Less scatter than the bo/tmb for sure, but no difference in sharpness detectable in average seeing.

Glad you like the Otho Geoff

Funny I find the seeing down here better than you have it Sab. Would seem that your suffering from heat from houses more than not I would say.

§AB · #17 23-05-2008, 06:36 PM

Bloody hell, everyone is having better seeing than me

Don't know Dave, you, me, Doug, Phil and Starkler all live in built up areas but you 4 seem to be reporting consistantly better conditions

Tonight I think looks better, less star twinkle, huge high pressure system right over us, all charts showing low wind velocities, forecast low 1ºC - everything, including concrete and houses will be frozen solid so it HAS to be good tonight.

I've got the 12" outside cooling now, don't think it'll reach ambient until around midnight. It is a dinner-plate sized piece of glass and the temp is dropping rapidly....

Dew will no doubt be tremendous, I just hope my mirrors don't fog up.