3
votes
2answers
169 views

WeatherData for the 15th day of each month

Suppose we have WeatherData["Helsinki", "MeanTemperature", {{2007, 1, 1}, {2012, 12, 31}, "Day"}] How we can have data just for 15th day of each month?
2
votes
1answer
149 views

Importing data from Excel for DateListPlot

I am importing data from Excel and plotting it with DateListPlot. My code is ...
17
votes
1answer
853 views

The Orbit and Perigee of the Flamsteed comet

Historical context This year we have the 330-th anniversary of the Battle of Vienna - one of the great formative events of European history, it took place on September 12, 1683. Kara Mustafa, Grand ...
9
votes
1answer
171 views

Why do DateList, DateString, and AstronomicalData ignore $TimeZone?

My reading of the documentation for DateList and DateString lead me to believe that both functions use ...
12
votes
2answers
342 views

How is AstronomicalData interpreting its date arguments?

It is easy to confirm that the AstronomicalData is not interpreting its arguments as UTC (or "GMT", which is, in any case, ambiguous) dates by verifying that the ...
12
votes
1answer
215 views

Is there a way to get AbsoluteTime to correctly report absolute time differences?

Absolute time supposedly reports the "total number of seconds" between two dates, but it does not. For example because of the leap second applied at 2012-06-30T23:59:60Z ...
9
votes
1answer
223 views

How do I determine astronomical transit times?

Mathematica, through the "legacy" Scientific Astronomer package, used to have the ability to easily determine accurate transit times of astronomical objects simply, with ...
6
votes
3answers
238 views

Determining the dates of days

I'm trying to use WeatherData[] to give me (not sure how) the temperature, humidity, wind-speed, cloud cover... at a certain location. I only want the information ...
9
votes
1answer
183 views

How can I convert the dates returned by FinancialData into decimal representation?

I'm trying to run a regression using Fit on the output of FinancialData["SPY", "Jan. 1, 2011"]. However, the dates returned ...