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Old 05-08-2018, 07:46 PM
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Stonius (Markus)
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Bad conditions, yet good seeing predicted in Melbourne?

It's been fairly windy today and it's not predicted to settle down. The jetstrean is not calm either, yet this site; predicts seeing in the range of 0.75 arc sec.

I thought the turbulence would have made the seeing poor, but it seems to have had the opposite effect. Weird.

Anyone know the explanation for this? Not sure if I'll get out there to test the predicted 'good seeing'.

Markus
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Old 05-08-2018, 10:54 PM
kens (Ken)
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Never got to find out once the clouds rolled in
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Old 06-08-2018, 09:21 AM
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Merlin66 (Ken)
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Markus,
An interesting site....but how do they calculate the seeing in arc sec from the ratings they show??
Different ratings (1&2) can give very similar results - some poor ratings give good seeing and vice versa....
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Old 06-08-2018, 10:08 PM
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Stonius (Markus)
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Quote:
Originally Posted by Merlin66 View Post
Markus,
An interesting site....but how do they calculate the seeing in arc sec from the ratings they show??
Different ratings (1&2) can give very similar results - some poor ratings give good seeing and vice versa....
I have no idea. It was recommended in another thread on IIS and I've been following it since trying to gauge its accuracy. I can't even find a more detailed explanation of exactly what index 1 and 2 actually refer to, but the arcseconds is pretty obvious and easy to follow.

Cheers

Markus
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Old 07-08-2018, 07:05 AM
Tropo-Bob (Bob)
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I am starting to follow this site. It does cover Cairns, so it looks very useful.

I am not sure how reliable it is, but it does highlight that attempting to split close doubles when the seeing is bad is perhaps not a good idea.
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Old 08-08-2018, 03:07 PM
morls (Stephen)
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Well, SkippySky suggests there *might* be some clear sky in melbourne's east tonight, but at the moment I'm sceptical...

Meteoblue (linked to above) suggests a lot of low cloud, but none in the medium to high altitude.
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Old 08-08-2018, 04:29 PM
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The Mekon (John Briggs)
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Recent days in the southern highlands of NSW have been mostly clear, with very clear horizons to the west. But on both Sunday night and last night seeing and transparency have been dreadful. Looked like I would to be a great night yesterday perhaps with some wind. Put out the 106mm on EQ6 as this has no problem with wind. Struggling to separate 1.5" double stars, just made out Cassini division and halos visible around 3rd mag stars using binoculars. So frustrating!
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Old 08-08-2018, 09:30 PM
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Quote:
Originally Posted by morls View Post
Well, SkippySky suggests there *might* be some clear sky in melbourne's east tonight, but at the moment I'm sceptical...

Meteoblue (linked to above) suggests a lot of low cloud, but none in the medium to high altitude.
Looking at the cloud predictions currently, Meteoblue seems to be more on the money than Cloud Free Night. CFN predicting clear skies. Meteoblue predicting 25% low cloud cover. Currently experiencing 100% cloud cover. :-/. Oh well. At least we have these tools at our disposal, not like when I was a kid.

Markus
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Old 08-08-2018, 09:48 PM
morls (Stephen)
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There were a few clear breaks tonight, so I got some time at the eyepiece. The skippysky prediction seems pretty lo-res, but it's ok.

Thanks for the link to meteoblue, it seemed pretty accurate for tonight's conditions.

Stephen
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Old 16-08-2018, 09:08 PM
morls (Stephen)
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Well, both skippysky and meteoblue weren't encouraging at all when I checked them out today, so I didn't expect to have the scope out tonight.

BUT....

I had a look outside at around 7pm, and it looked promising, so I set up and had a great time until the dew got the better of me (note to self - remember to use the dew shield at all times!)

I think it was the best seeing I've had since getting the scope, well worth the effort. I had a good look at Mars, and I'm not sure but I think I might have seen a polar cap - not on top but at around 10-11 o'clock there was a bright patch that suggested (to me at least) light reflecting. It was certainly different to the rest of the globe, which was uniformly reddish but no detail...

I also got some beautiful views of the moon through the 35mm panoptic. Wow. (attached pic from phone held to eyepiece, it's pretty bad but gives an idea of the FOV with the panoptic)

Seems the astro weather sites can be wrong...still, a pretty good resource.
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Old 18-08-2018, 10:20 AM
foc (Ross)
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I have started paying attention to Metrobleu as well as my more commonly used Cloudfree night sites recently since I can only usually get out once or twice a week, sometimes that late after work and would like to pick the best days.

I know all these sites use models which are a bit simplistic and only rough for local viewing and its local variables, but if I find one correlates well and gives easy to interpret info it would be very helpful.
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Old 18-08-2018, 11:35 AM
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I have started paying attention to Metrobleu as well as my more commonly used Cloudfree night sites recently since I can only usually get out once or twice a week, sometimes that late after work and would like to pick the best days.

I know all these sites use models which are a bit simplistic and only rough for local viewing and its local variables, but if I find one correlates well and gives easy to interpret info it would be very helpful.
Same. Nothing worse than setting up because you think the forecasts were wrong, only to find out that they were right. Especially when you have to travel & setup / packdown.
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