Astronomical weather forecast

Got a question on astronomy that you'd wanted to ask? Ask your questions here and see if the old timers can give you some good answers.
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Canopus Lim
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Joined: Fri Jun 03, 2005 12:46 pm
Location: Macpherson

Post by Canopus Lim »

I think what is the most limiting factor is cloud cover and light pollution. If there is no clouds, even lousy transparency, we can at least see stars though harder to see nebula as what Jeremy has said. It is hard to find days here when there are no clouds.
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thetno
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Joined: Thu Dec 30, 2004 7:58 pm

Post by thetno »

this will certainly help us a lot and it looks pretty accurate.
our club got difficulties planning for obing and our NEA's forecast is always showing cloudy.

thanks!
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jermng
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Joined: Tue May 17, 2005 7:09 am

Post by jermng »

Actually, I think the forecast leans towards the negative side ... :) Been out on a quite a few good nights last 2 weeks when the forecast showed 70%-overcast readings .... :)
Yesterday's skies were so blue from 8am to bout noon but the clock showed 70% clouds all the way ... :)
It does give a good overview though ... :)
Jeremy Ng
C8, CR-150HD, TMB 80 f/6
Orion SVP Intelliscope, AstroSlew I
Minolta Activa 12x50WA
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Tachyon
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Joined: Wed Jun 01, 2005 11:40 am
Location: Bedok

Post by Tachyon »

Weather forecasting, like Stock Market predictions, are only an indication of the future based on current knowledge. I use it to plan my social life, not skywatching - if it says >50% cloudy, I plan for a movie. However, if it says <20% cloudy, then I will start preparing my gear but still watch the skies before I leave. :-P

(p.s. A bit off topic - thetno: your avatar is funny!)
[80% Steve, 20% Alfred] ------- Probability of Clear Skies = (Age of newest equipment in days) / [(Number of observers) * (Total Aperture of all telescopes present in mm)]
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Canopus Lim
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Joined: Fri Jun 03, 2005 12:46 pm
Location: Macpherson

Post by Canopus Lim »

For weather forecast in Spore, I will check Nowcast. It gives the current cloud condition for all parts of Spore and prediction. It is 3h update frequency and it is quite good. However, I will always check the sky before I leave to ob. Going for ob in Spore is always a risk. :P
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weixing
Super Moderator
Posts: 4708
Joined: Wed Oct 01, 2003 12:22 am
Favourite scope: Vixen R200SS & Celestron 6" F5 Achro Refractor
Location: (Tampines) Earth of Solar System in Orion Arm of Milky Way Galaxy in Local Group Galaxies Cluster

Post by weixing »

Hi,
This is the link ( http://7timer.y234.cn/V3/index.php?language=en ) to the Astroweather panel... similar to Clear Sky Chart in the US.

I think it's the same guy and now even better as it's cover two millions cities, towns and villages over the world... of course area in Singapore and Malaysia are included.

Hmm... now, let's see "weather" it is accurate... :mrgreen:

Have a nice day.
Yang Weixing
:mrgreen: "The universe is composed mainly of hydrogen and ignorance." :mrgreen:
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Tachyon
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Joined: Wed Jun 01, 2005 11:40 am
Location: Bedok

Post by Tachyon »

Oh, it's back!
[80% Steve, 20% Alfred] ------- Probability of Clear Skies = (Age of newest equipment in days) / [(Number of observers) * (Total Aperture of all telescopes present in mm)]
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neoterryjoe
Posts: 289
Joined: Sun Nov 14, 2004 12:15 pm
Favourite scope: c5
Location: je ( 1.34, 103.73 )

Post by neoterryjoe »

wooo..nice tool
a bit confused though, about the colour code for seeing and transparency.
Seeing-
"The seeing here is a reference to the best possible angular resolution which can be achieved by an optical telescope."
So the more the resolution the better(white is better than blue)? Doesnt sound right to the inituitive mind - blue(signifying night sky) is supposed to be better than white correct?
Transparency -
"The transparency here is an integrated measure of the extinction of sky objects."
Measured in magnitude/air mass, so is the magnitude refering to the limiting magnitude or just a normal scale from 0 - >1? Seems to me the latter from the scale used. So the less(<0.3, blue) the better?
hmm.. maybe they should just follow cleardarksky.com in putting in plain english, transparent, not transparent.
Somebody has a clearer idea of this?
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weixing
Super Moderator
Posts: 4708
Joined: Wed Oct 01, 2003 12:22 am
Favourite scope: Vixen R200SS & Celestron 6" F5 Achro Refractor
Location: (Tampines) Earth of Solar System in Orion Arm of Milky Way Galaxy in Local Group Galaxies Cluster

Post by weixing »

Hi,
neoterryjoe wrote:wooo..nice tool
a bit confused though, about the colour code for seeing and transparency.
Seeing-
"The seeing here is a reference to the best possible angular resolution which can be achieved by an optical telescope."
So the more the resolution the better(white is better than blue)? Doesnt sound right to the inituitive mind - blue(signifying night sky) is supposed to be better than white correct?
Transparency -
"The transparency here is an integrated measure of the extinction of sky objects."
Measured in magnitude/air mass, so is the magnitude refering to the limiting magnitude or just a normal scale from 0 - >1? Seems to me the latter from the scale used. So the less(<0.3, blue) the better?
hmm.. maybe they should just follow cleardarksky.com in putting in plain english, transparent, not transparent.
Somebody has a clearer idea of this?
A brief instructions on how to read the graph is presented at the bottom of that page. Basically, towards blue is good and towards white is bad.

Have a nice day.
Yang Weixing
:mrgreen: "The universe is composed mainly of hydrogen and ignorance." :mrgreen:
Crodol
Posts: 2
Joined: Mon Jul 27, 2009 9:34 am
Location: Singapore

Post by Crodol »

What are your experiences with 7Timer?

I have the feeling it's only a bit better than NEA... but still the best that is out there...
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