SKIPPYSKY HELP                      

SkippySky uses the "high resolution" GFS data from NOAA/NCEP.
This data has a resolution of 0.5 degrees, that is, there are
only four (4) data points per square degree of longitude/latitude,
or one data point for every 30x30 kilometre square patch of ground
(Approximately).

So, Yes, it's not exactly "high resolution", is it... ;-)

Notwithstanding that, the GFS model is quite accurate most of
the time. I urge you to think of trends in the data when you look
at the SkippySky maps rather than thinking about what you expect
to see right above the clotheline in your backyard at any given hour.
I'm sure that you will still be pleasantly surprised.

This is the same data source that several other astronomy forecast
sites use, e.g. 7Timer, astroforecast.org, meteoblue, and probably others.

Now, if I plotted the actual data, you'd see square patches of various
colours, four per square degree. That can be difficult to interpret,
hence the data is contoured to make it easier on the eye and on the brain.

So now we have 0.5 degree resolution data that has been further smoothed
by the contouring algorithm. Please keep this in the back of your mind
when assessing SkippySky maps. Balance off the likelihood of clouds
moving around in rigid half degree square shapes versus the slightly
more fluffy trends suggested by SkippySky.

Indeed, this brings us to SkippySky's Raison d'être. I could never see
the point of plugging in an exact set of latitude/longitude coordinates
and expecting an exact forecast from the 0.5 degree GFS model data, as
some of my esteemed competitors ask you to do.

SkippySky presents broad weather information across a wide area.
You know best how your local weather systems move - SkippySky lets
you see what's heading your way from over the horizon. 

******* COLOUR SCALES ********

After much debate during the early days of SkippySky, a standard
colour theme was adopted for all parameters, where ;-

RED  = BAD
BLUE = Good


The only possible exception to this might be Pressure, where it could be argued
that low pressure means stormy = Bad. I've got used to it. You will too ;-)


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Some notes on the derived fields TRANSPARENCY and SEEING and DEW RISK
======================================================================

TRANSPARENCY describes the amount of water vapour in the air. This
affects how much starlight makes it into your scope. The lack of 
visible clouds does not necessarily mean no water vapour and thus
high transparency. Conversely, the presence of clouds pretty much
guarantees low transparency values.

SEEING. A hairy topic. No clear consensus amongst amateurs or in
the available professional literature that I've been able to source.
Accordingly, SkippySky makes no attempt to assign a Seeing index
measured in arcseconds. Our 0..10 index is merely a weighted scale
based on wind vectors at 10metres and at the Tropoapuse (aka Jetstream)

Red on the Seeing scale means stay inside and have a red wine - 
Seeing will most likely be atrocious. Blue means get out there and
turn blue in the cold, 'cos the Seeing is likely to be worth it.

DEW RISK

Derived from Sky Temperature & Relative Humidity, Dew Risk is a measure of
the likelihood of dew forming on the surface of an exposed 200mm (8") mrror.
Anything below 0 is likely to warrant turning on your dew heaters.
The Index is a differential measured in Degrees K (Kelvin).
Do not attempt to relate 10 to 10C (or 10F for the Americans) - it doesn't work that way!
Just be happy if the Dew Risk Index is above 0.

Of course, the design of your scope, and its location with respect to ground and
proctection provided by any observatory structure will give a different Dew Risk from a
nominal 200mm exposed mirror. Take the sclae as relative to your situation after
matching it against your local observing environment.

========================================================================

As I've stressed above, think of trends in the data. The darker the
blue, the more likely the Seeing will be better. If you can assign
an arcsecond equivalent to that scale based on actual observations,
or from DIMM readings, please drop me an email at contact@skippysky.com.au,
and if others agree with you, we'll look at changing the scale.

I have set up a Yahoo Group for SkippySky at :-
http://tech.groups.yahoo.com/group/skippysky/

should anyone wish to discuss SkippySky issues.

Andrew Cool
August '09