# sunspot.month

##### Monthly Sunspot Data, from 1749 to "Present"

Monthly numbers of sunspots, as from the World Data Center, aka SIDC. This is the version of the data that will occasionally be updated when new counts become available.

- Keywords
- datasets

##### Usage

`sunspot.month`

##### Format

The univariate time series `sunspot.year`

and
`sunspot.month`

contain 289 and 2988 observations, respectively.
The objects are of class `"ts"`

.

##### Source

WDC-SILSO, Solar Influences Data Analysis Center (SIDC), Royal Observatory of Belgium, Av. Circulaire, 3, B-1180 BRUSSELS Currently at http://www.sidc.be/silso/datafiles

##### See Also

`sunspot.month`

is a longer version of `sunspots`

;
the latter runs until 1983 and is kept fixed (for reproducibility as example
dataset).

##### Examples

`library(datasets)`

```
require(stats); require(graphics)
## Compare the monthly series
plot (sunspot.month,
main="sunspot.month & sunspots [package'datasets']", col=2)
lines(sunspots) # -> faint differences where they overlap
## Now look at the difference :
all(tsp(sunspots) [c(1,3)] ==
tsp(sunspot.month)[c(1,3)]) ## Start & Periodicity are the same
n1 <- length(sunspots)
table(eq <- sunspots == sunspot.month[1:n1]) #> 132 are different !
i <- which(!eq)
rug(time(eq)[i])
s1 <- sunspots[i] ; s2 <- sunspot.month[i]
cbind(i = i, time = time(sunspots)[i], sunspots = s1, ss.month = s2,
perc.diff = round(100*2*abs(s1-s2)/(s1+s2), 1))
## How to recreate the "old" sunspot.month (R <= 3.0.3):
.sunspot.diff <- cbind(
i = c(1202L, 1256L, 1258L, 1301L, 1407L, 1429L, 1452L, 1455L,
1663L, 2151L, 2329L, 2498L, 2594L, 2694L, 2819L),
res10 = c(1L, 1L, 1L, -1L, -1L, -1L, 1L, -1L,
1L, 1L, 1L, 1L, 1L, 20L, 1L))
ssm0 <- sunspot.month[1:2988]
with(as.data.frame(.sunspot.diff), ssm0[i] <<- ssm0[i] - res10/10)
sunspot.month.0 <- ts(ssm0, start = 1749, frequency = 12)
```

*Documentation reproduced from package datasets, version 3.1.1, License: Part of R 3.1.1*

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