Converts year number (epoch) to calendar year

Description

Converts year number (epoch) to calendar year

Usage

BC.AD(year)

Arguments

Examples

BC.AD(100)
BC.AD(0)
BC.AD(-1)
BC.AD(-99)
BC.AD(-100)

Equinoctial Full Moons

Description

This function calculates the date, rise/set times, azimuth and declination for sun and moon on the days of the Spring Full Moon (SFM) and Autumn Full Moon (AFM), for a given year and location.

Usage

EFM(
  season = "spring",
  rise = T,
  year,
  loc,
  min.phase = 0.99,
  refraction,
  atm,
  temp,
  timezone,
  calendar
)

Arguments

Examples

# Spring Full Moon from a location in Portugal in the year 2018
EFM(year=2018, loc=c(35,-8,100))

# Autumn Full Moons in the last three years
## Not run: 
EFM(season='autumn', year=c(2019,2021), loc=c(35,-8,100))

## End(Not run)

Cork and Kerry Stone Row Data

Description

Data from C.L.N. Ruggles' fieldwork on the Stone Rows of Cork and Kerry.

Usage

data(RugglesCKR)

Format

A data frame with 41 rows and 5 variables:

Ref

Site Ref

NE.SW

String indicating whether they are towards the NE or SW

Az.Hill

Azimuth of hill towards which the Stone Rows are pointing

Alt.Hill

Altitude of hill towards which the Stone Rows are pointing

Dec.Hill

Declination of hill towards which the Stone Rows are pointing

References

Ruggles, C.L.N. (1999). Astronomy in Prehistoric Britain and Ireland. Yale University Press.

Examples

data(RugglesCKR)
kde <- density(RugglesCKR$Dec.Hill, 2)
plot(kde)

Recumbent Stone Circle Data

Description

Declination data from C.L.N. Ruggles' fieldwork on the Scottish Recumbent Stone Circles.

Usage

data(RugglesRSC)

Format

A data frame with 37 rows and 2 variables:

Dec

Declination

ID

Site ID

References

Ruggles, C.L.N. (1999). Astronomy in Prehistoric Britain and Ireland. Yale University Press.

Examples

data(RugglesRSC)
kde <- density(RugglesRSC$Dec, 2)
plot(kde)

Declination of the anti-zenith sun for a given location

Description

This function returns the declination of the sun when it is at the anti-zenith for a given location with corrected average parallax. If this phenomena does not occur at given location (i.e. if location is outside the tropical band) the function returns a NULL value.

Usage

antizenith(loc, parallax = 0.00224, altitude = 0)

Arguments

See Also

jS, dS, eq, zenith, spatial.equinox, parallax.corr

Examples

# Anti-zenith sun declination for Mexico City:
antizenith(19.419)

# There is no anti-zenith sun phenomena in London:
antizenith(51.507)

Convert discrete azimuth measurements into probability distributions

Description

Convert discrete azimuth measurements into probability distributions

Usage

az.pdf(
  pdf = "normal",
  az,
  unc,
  name,
  verbose = T,
  .cutoff = 1e-04,
  .res = 0.01
)

Arguments

References

Silva, F (2020) A probabilistic framework and significance test for the analysis of structural orientations in skyscape archaeology Journal of Archaeological Science 118, 105138. <doi:10.1016/j.jas.2020.105138>

Examples

test <- az.pdf(az=c(87,93,90,110), unc=3)
plot(test)

Calculates declination from azimuth and altitude measurements

Description

This function calculates the declination corresponding to an orientation , i.e. an azimuth. The altitude can either be given or, alternatively, if a skyscapeR.horizon object is provided, the corresponding horizon altitude will be automatically retrieved. This function is a wrapper for function swe_azalt_rev of package swephR.

Usage

az2dec(
  az,
  loc,
  alt,
  refraction = skyscapeR.env$refraction,
  atm = skyscapeR.env$atm,
  temp = skyscapeR.env$temp
)

Arguments

See Also

swe_azalt_rev, hor2alt

Examples

dec <- az2dec(az=92, loc=c(35,-8), alt=2)

# flat horizon with 2 degrees of altitude
hor <- createHor(az=c(0,360), alt=c(2,2), loc=c(35,-8,25))
dec <- az2dec(92, loc=hor)

# Can also be used for an array of azimuths:
decs <- az2dec(az=c(87,92,110), loc=hor)

Execute a (series of) Bernoulli trial(s)

Description

This function allows one to calculate the probability of having r structures out of n, orientated towards a target with probability p.

Usage

bernoulli.trial(n, p, r, type = "tail")

Arguments

References

Ruggles, C (1999) Astronomy in Prehistoric Britain and Ireland. Yale University Press.

Examples

# probability of having at least 10 out of 30 structures
# aligned to targets covering 20% of the horizon
bernoulli.trial(30, 0.2, 10)

Computes position of Solar System bodies in equatorial coordinates

Description

This function calculates the geocentric or topocentric declination and right ascension of solar system bodies at a given time. It is a wrapper for function swe_calc_ut of package swephR.

Usage

body.position(
  obj = "sun",
  time,
  timezone,
  calendar,
  dec,
  loc = NULL,
  refraction,
  atm,
  temp,
  verbose = T
)

Arguments

See Also

swe_calc_ut, timestring, time2jd

Examples

# Position of the sun at noon GMT on Christmas day 2018:
body.position('sun', '2018/12/25 12:00:00', timezone='GMT')

# Declination of the moon at same time
body.position('moon', '2018/12/25 12:00:00', timezone='GMT')$equatorial$Dec

Coordinate-transform azimuth prob distributions into declination prob distributions

Description

Coordinate-transform azimuth prob distributions into declination prob distributions

Usage

coordtrans(pdf, hor, refraction, atm, temp, verbose = T, .res = 0.1)

Arguments

References

Silva, F (2020) A probabilistic framework and significance test for the analysis of structural orientations in skyscape archaeology Journal of Archaeological Science 118, 105138. <doi:10.1016/j.jas.2020.105138>

Examples

Az <- az.pdf(az=c(87,93,90,110), unc=3)
hor <- createHor(az=c(0,360), alt=c(0,0), loc=c(35,-8,25)) # flat horizon with 0 degrees of altitude
Dec <- coordtrans(Az, hor)
plot(Dec)

Create and download horizon data from HeyWhatsThat

Description

This function send a data request to HeyWhatsThat, for the creation of a horizon profile for a give Lat/Lon and elevation. It then downloads the data and saves it as a skyscapeR.horizon object.

Usage

createHWT(lat, lon, elevation = 1.6, name, src = "skyscapeR", verbose = T)

Arguments

References

HeyWhatsThat.com

See Also

downloadHWT

Examples

## Not run: 
# Create and retrieve horizon data for the London Mithraeum:
hor <- createHWT(lat=ten(51,30,45), lon=ten(0,5,26.1), name='London Mithraeum')

## End(Not run)

Create skyscapeR.horizon object from Az/Alt data

Description

This function creates a skyscapeR.horizon object from measurements of azimuth and altitude.

Usage

createHor(az, alt, alt.unc = 0.5, loc, name = "", smooth = F, .scale = 1000)

Arguments

See Also

plot.skyscapeR.horizon

createHWT, downloadHWT

Examples

# Create a skyscapeR.horizon from 5 measurements:
az <- c(0,90,180,270,360)
alt <- c(0,5,5,0,0)
hor <- createHor(az, alt, 0.1, c(40.1,-8), 'Test')
plot(hor)

(Defunct) Computes declination curvigram

Description

This function no longer works. Please use spd of density instead.

Usage

curvigram()

See Also

spd

Declination of December Solstice for a given year

Description

This function calculates the declination of the sun at December Solstice for a given year, based upon obliquity estimation and corrected average parallax.

Usage

dS(
  year = skyscapeR.env$cur.year,
  loc = FALSE,
  parallax = 0.00224,
  altitude = 0,
  verbose = TRUE
)

Arguments

See Also

obliquity, jS, eq, zenith, antizenith, spatial.equinox, parallax.corr

Examples

# December Solstice geocentric declination for year 4001 BC:
dS(-4000)

# Topocentric declination for same year and latitude of 50 degrees N:
dS(-4000, loc=50)

Download horizon data from HeyWhatsThat

Description

This function downloads previously created horizon data from HeyWhatsThat, given its ID, and saves it as a skyscapeR.horizon object.

Usage

downloadHWT(HWTID)

Arguments

References

HeyWhatsThat.com

See Also

createHWT

Examples

## Not run: 
# Retrieve horizon data for \href{https://www.heywhatsthat.com/?view=HIFVTBGK}{Liverpool Cathedral}:
hor <- downloadHWT('HIFVTBGK')

## End(Not run)

Declination of the sun at the Equinox

Description

This function calculates the declination of the sun at the astronomical equinox with corrected average parallax.

Usage

eq(loc = FALSE, parallax = 0.00224, altitude = 0, verbose = TRUE)

Arguments

See Also

obliquity, jS, eq, zenith, antizenith, spatial.equinox, parallax.corr

Examples

# Equinoctial geocentric declination:
eq()

# Topocentric declination for same year and latitude of 50 degrees N:
eq(loc=50)

Exports a skyscapeR.horizon object into Stellarium format

Description

This function exports any skyscapeR.horizon object into the landscape format of Stellarium, ready to be imported.

Usage

exportHor(hor, name, author = "skyscapeR", description, ground_col, hor_col)

Arguments

References

Stellarium: a free open source planetarium

See Also

createHor, downloadHWT, plot.skyscapeR.horizon

Examples

# Downloads horizon data from HeyWhatsThat and exports it into Stellarium:
## Not run: 
hor <- downloadHWT('HIFVTBGK')
exportHor(hor, name='Test', description='Test horizon export to Stellarium')

## End(Not run)

Find celestial targets within declination and time ranges

Description

Find celestial targets within declination and time ranges

Usage

findTargets(
  decrange,
  timerange,
  max.mag = 2.5,
  loc = FALSE,
  calendar = skyscapeR.env$calendar
)

Arguments

Examples

## Not run: 
findTargets(c(-25,-17.5), c(-2500,-1750))

# if a location is given then the zenith and anti-zenith sun will also be looked at:
findTargets(c(3,12), c(-2500,-1750), loc=c(8.6, 7.3, 200))

# if a horizon profile is given then the spatial equinox will also be looked at:
hor <- downloadHWT('J657KVEV')
findTargets(c(-7,2), c(-2500,-1750), loc=hor)

## End(Not run)

Retrieves horizon altitude for a given azimuth from a given horizon profile

Description

This function retrieves the horizon altitude for a given azimuth from a previously created skyscapeR.horizon object via spline interpolation.

Usage

hor2alt(hor, az, return.unc = F)

Arguments

See Also

createHor, downloadHWT

Examples

hor <- downloadHWT('HIFVTBGK')
hor2alt(hor, 90)

Returns the high-density region of a probability distribution

Description

Returns the high-density region of a probability distribution

Usage

hpdi(x, mass = 0.954)

Arguments

Declination of June Solstice for a given year

Description

This function calculates the declination of the sun at June Solstice for a given year, based upon obliquity estimation and corrected average parallax.

Usage

jS(
  year = skyscapeR.env$cur.year,
  loc = FALSE,
  parallax = 0.00224,
  altitude = 0,
  verbose = TRUE
)

Arguments

See Also

obliquity, dS, eq, zenith, antizenith, spatial.equinox, parallax.corr

Examples

# June Solstice geocentric declination for year 4001 BC:
jS(-4000)

# Topocentric declination for same year and latitude of 50 degres N:
jS(-4000, loc=50)

Converts Julian date and time (in any timezone) to julian date

Description

Converts Julian date and time (in any timezone) to julian date

Usage

jd2time(jd, timezone, calendar, verbose = F)

Arguments

See Also

swe_julday, as.POSIXlt, timezones

Examples

jd <- time2jd('2018/12/25 12:00:00', 'GMT') # Julian date at noon GMT on Christmas day 2018
jd2time(jd, 'CET') # converts julian date to Central European timezone

Converts day-month in 'MM-DD' format to a more readable format

Description

Converts day-month in 'MM-DD' format to a more readable format

Usage

long.date(date)

Arguments

Examples

long.date('01-01')
long.date('08-23')

Estimates magnetic declination (difference between true and magnetic north) based on IGRF 12th gen model

Description

This function estimates the magnetic declination at a given location and moment in time, using the 12th generation International Geomagnetic Reference Field (IGRF) model. This function is a wrapper for function magneticField of package oce.

Usage

mag.dec(loc, date)

Arguments

See Also

magneticField

Examples

# Magnetic Declination for London on April 1st 2016:
loc <- c( 51.5074, -0.1278 )
mag.dec( loc, "2016/04/01" )

Computes the phase of the moon

Description

This function calculates the moon phase, in percentage of full. It is a wrapper for function swe_pheno_ut of package swephR.

Usage

moonphase(time, timezone, calendar)

Arguments

See Also

swe_pheno_ut

Examples

# Moonphase at noon GMT on Christmas day 2018:
moonphase('2018/12/25 12:00:00', 'GMT')

Declination of northern major Lunar Extreme for a given year

Description

This function calculates the declination of the northern major Lunar Extreme for a given year, based upon obliquity estimation and corrected average parallax.

Usage

nMjLX(
  year = skyscapeR.env$cur.year,
  loc = FALSE,
  parallax = 0.952,
  altitude = 0,
  verbose = TRUE
)

Arguments

See Also

nmnLX, smnLX, sMjLX, parallax.corr

Examples

# Northern major Lunar Extreme geocentric declination for year 2501 BC:
nMjLX(-2500)

# Topocentric declination for same year and latitude of 50 degrees N:
nMjLX(-2500, loc=50)

Declination of northern minor Lunar Extreme for a given year

Description

This function calculates the declination of the northern minor Lunar Extreme for a given year, based upon obliquity estimation and corrected average parallax.

Usage

nmnLX(
  year = skyscapeR.env$cur.year,
  loc = FALSE,
  parallax = 0.952,
  altitude = 0,
  verbose = TRUE
)

Arguments

See Also

smnLX, nMjLX, sMjLX, parallax.corr

Examples

# Northern minor Lunar Extreme geocentric declination for year 2501 BC:
nmnLX(-2500)

# Topocentric declination for same year and latitude of 50 degrees N:
nmnLX(-2500, loc=50)

Computes obliquity of the ecliptic

Description

This function calculates the obliquity for a given epoch. It is a wrapper for function swe_calc_ut of package swephR.

Usage

obliquity(year = skyscapeR.env$cur.year)

Arguments

References

Laskar, J. et al. (2004), A long-term numerical solution for the insolation quantities of the Earth, Astron. Astroph., 428, 261-285, doi:10.1051/0004-6361:20041335.

See Also

swe_calc_ut

Examples

#' # Obliquity for year 3999 BC:
obliquity(-4000)

Calculate visible path of celestial object at given location

Description

This function calculates the visible path of a celestial object from any location on earth. It outputs a skyscapeR.orbit object, which includes AZ and ALT information.

Usage

orbit(dec, loc, res = 0.25, refraction, atm, temp)

Arguments

Examples

# Visible path of sun on june solstice on year 3999 BC from London:
sun.dec <- jS(-4000)
london.lat <- 51.5074 #N
london.lon <- -0.1278 #W
loc <- c( london.lat, london.lon, 0 )
path <- orbit(sun.dec, loc)
plot(path$az, path$alt, ylim=c(0,90), type='l', xlab='AZ', ylab='ALT', col='red', lwd=2)

Corrected parallax for a given location and object altitude

Description

Given the average parallax, this function corrects this value for a given latitude of the observer and for the altitude of the celestial object.

Usage

parallax.corr(parallax, loc, altitude = 0)

Arguments

Examples

# Parallax correction for the moon, as seen from latitude 50ºN and at 0º altitude
parallax.corr(0.952, 50, 0)

Plot horizon data

Description

This function creates a plot of horizon data.

Usage

## S3 method for class 'skyscapeR.horizon'
plot(
  x,
  show.az = F,
  xlim,
  ylim,
  obj,
  refraction = F,
  col.ground = "#fdae61",
  ...
)

Arguments

See Also

downloadHWT, sky.objects

Examples

# Plot a horizon retrieved from HeyWhatsThat:
hor <- downloadHWT('HIFVTBGK')
plot(hor)

# Add the paths of the solstices and equinoxes sun in the year 1999 BC:
tt <- sky.objects('solar extremes', epoch=-2000, col='blue')
plot(hor, obj=tt)

Plot orientation probability distributions

Description

Plot orientation probability distributions

Usage

## S3 method for class 'skyscapeR.pdf'
plot(
  x,
  index,
  hdr = 0.954,
  show.az = T,
  xlim,
  col = MESS::col.alpha("blue", 0.5),
  ...
)

Arguments

Plot significance test of orientations

Description

Plot significance test of orientations

Usage

## S3 method for class 'skyscapeR.sigTest'
plot(
  x,
  xlim,
  title = NULL,
  show.pval = T,
  show.local = F,
  pal = brewer.pal(5, "PRGn")[c(1, 5)],
  ...
)

Arguments

Plot orientation summed probability density

Description

Plot orientation summed probability density

Usage

## S3 method for class 'skyscapeR.spd'
plot(x, xlim, ylim, title = NULL, col = "blue", shading = T, ...)

Arguments

Plot stellar phase and seasonality

Description

This function creates a plot of stellar seasonality and phases/events.

Usage

## S3 method for class 'skyscapeR.starphases'
plot(x, ...)

Arguments

See Also

star.phases

Examples

# Plot the seasonality of Aldebaran for 3999 BCE:
## Not run: 
ss <- star.phases('Aldebaran',-4000, c(35,-8, 200))
plot(ss)

## End(Not run)

Polar plot of orientations (azimuths)

Description

Polar plot of orientations (azimuths)

Usage

plotAzimuth(az, col = "blue", lwd = 1.5, lty = 1, obj, show.obj.labels = T)

Arguments

Examples

# Plot some azimuth data:
az <- c(120, 100, 93, 97, 88, 115, 112, 67)
plotAzimuth(az)

# To visualize this data against the common solar and lunar targets:
tt <- sky.objects('solar extremes', epoch=-2000, loc=c(35,-8), col='red')
plotAzimuth(az, obj=tt)

# To display only celestial objects
plotAzimuth(obj=tt)

Bar plot of orientations (declination)

Description

Bar plot of orientations (declination)

Usage

plotBars(
  val,
  unc,
  names,
  unit = "Declination",
  col = "blue",
  shade = TRUE,
  mark = TRUE,
  sort = FALSE,
  xrange,
  yrange,
  obj,
  show.obj.label = TRUE
)

Arguments

See Also

sky.objects

Examples

# Plot some declination data:
decs <- c(10, 12, -5, 4)
plotBars(decs, unc=5)

# To visualize this data against the common solar and lunar targets:
tt <- sky.objects(c('solar extremes','lunar extremes'), epoch=-2000, lty=c(2,3))
plotBars(decs, unc=5, obj=tt)

Prints significance test results

Description

This function prints the results of randomTest.

Usage

## S3 method for class 'skyscapeR.sigTest'
print(x, ...)

Arguments

See Also

randomTest

Converts p-value into symbol

Description

Converts p-value into symbol

Usage

pval2stars(p.value)

Arguments

Significance test against the null hypothesis of random orientation

Description

Significance test against the null hypothesis of random orientation

Usage

randomTest(
  pdf,
  nsims = 1000,
  conf = 0.95,
  tails = 2,
  normalise = F,
  ncores = parallel::detectCores() - 1,
  save.sim = F,
  verbose = T
)

Arguments

References

Silva, F (2020) A probabilistic framework and significance test for the analysis of structural orientations in skyscape archaeology Journal of Archaeological Science 118, 105138. <doi:10.1016/j.jas.2020.105138>

Examples

## Not run: 
# significance test for azimuth
Az <- az.pdf(az=c(87,93,90,110), unc=3)
st1 <- randomTest(Az, nsims=1000)
plot(st1)

# significance test for declination
hor <- createHor(az=c(0,360), alt=c(0,0), loc=c(35,-8,25)) # flat horizon with 0 degrees of altitude
Dec <- coordtrans(Az, hor)
st2 <- randomTest(Dec, nsims=1000)
plot(st2)

## End(Not run)

Data reduction for compass measurements

Description

This function calculates the true azimuth of a structure measured with a compass.

Usage

reduct.compass(loc, mag.az, date, magdec, alt, name, ID, HWT.ID)

Arguments

See Also

mag.dec, az2dec, hor2alt

Examples

loc <- c(35,-7, 100)
mag.az <- c(89.5, 105, 109.5)
data <- reduct.compass(loc, mag.az, "2016/04/02")

# Declination will be automatically calculated if the altitude is also given:
data <- reduct.compass(loc, mag.az, "2016/04/02", alt=c(1,2,0))

# Alternatively, the altitude can be automatically retrieved from a horizon profile:
hor <- downloadHWT('HIFVTBGK')
data <- reduct.compass(hor, mag.az, "2016/04/02")

Data reduction for theodolite measurements using the sun-sight method

Description

This function calculates the true azimuth of a structure measured with a theodolite using the sun-sight technique.

Usage

reduct.theodolite(
  loc,
  az,
  date,
  time,
  tz,
  az.sun = 0,
  limb,
  alt,
  name,
  ID,
  HWT.ID
)

Arguments

References

Ruggles, C.L.N. (1999). Astronomy in Prehistoric Britain and Ireland. Yale University Press.

See Also

sunAz, ten

Examples

lat <- ten(35,50,37.8)
lon <- ten(14,34,6.4)
elev <- 100
az <- c( ten(298,24,10), ten(302,20,40))
az.sun <- ten(327,29,50)
date <- "2016/02/20"
time <- "11:07:17"

data <- reduct.theodolite(c(lat,lon,elev), az, date , time, tz= "Europe/Malta", az.sun)

# Declination will be automatically calculated if the altitude is also given:
data <- reduct.theodolite(c(lat,lon,elev), az, date , time, tz= "Europe/Malta", az.sun, alt=c(2,5))

# Alternatively, the altitude can be automatically retrieved from a horizon profile:
hor <- downloadHWT('HIFVTBGK')
data <- reduct.theodolite(hor, az, date, time, tz= "Europe/Malta", az.sun)

Computes the rising and setting azimuth, declination and time of a Solar System object for a given location and day

Description

Computes the rising and setting azimuth, declination and time of a Solar System object for a given location and day

Usage

riseset(
  obj = "sun",
  date,
  jd,
  alt = 0,
  loc,
  calendar,
  timezone,
  dec,
  refraction,
  atm,
  temp,
  verbose = T
)

Arguments

See Also

swe_calc_ut, swe_azalt

Examples

# Rising and setting of the sun on june solstice 2018, from the location of London
riseset('sun', '2018/06/21', loc=c(51.5, 0.11, 100))

# Rising ans setting of the moon on june solstice 2018, using a horizon profile
hor <- downloadHWT('HIFVTBGK') # Liverpool cathedral
riseset('moon', '2018/06/21', loc=hor)

# Rising and setting of the sun throughout February 1999, from the location of London
riseset('sun', '1999/02', loc=c(51.5, 0.11, 100))

## Not run: 
# Rising and setting of the sun throughout 3001 BC, from the location of London
riseset('sun', -3000, loc=c(51.5, 0.11, 100))

## End(Not run)

Declination of southern major Lunar Extreme for a given year

Description

This function calculates the declination of the southern major Lunar Extreme for a given year, based upon obliquity estimation and corrected average parallax.

Usage

sMjLX(
  year = skyscapeR.env$cur.year,
  loc = FALSE,
  parallax = 0.952,
  altitude = 0,
  verbose = TRUE
)

Arguments

See Also

nmnLX, smnLX, nMjLX, parallax.corr

Examples

# Southern major Lunar Extreme geocentric declination for year 2501 BC:
sMjLX(-2500)

# Topocentric declination for same year and latitude of 50 degrees N:
sMjLX(-2500, loc=50)

(Defunct) Perform a null hypothesis significance test of a given curvigram

Description

This function no longer works. Please use randomTest instead.

Usage

sigTest()

See Also

randomTest

Creates a skyscapeR.object for plotting of celestial objects at given epoch

Description

This function creates an object containing all the necessary information to plot celestial objects/events unto the many plotting functions of skyscapeR package.

Usage

sky.objects(names, epoch, loc = FALSE, col = "red", lty = 1, lwd = 1)

Arguments

Examples

# Create a object with solar targets for epoch range 4000-2000 BC:
tt <- sky.objects('solar extremes', c(-4000,-2000))

# Create an object with a few stars for same epoch:
tt <- sky.objects(c('Sirius', 'Betelgeuse', 'Antares'), c(-4000,-2000),
col=c('white', 'red', 'orange'))

# Create an object with solstices and a custom declination value:
tt <- sky.objects(c('December Solstice','June Solstice', -13), c(-4000,-2000))

Create a simplistic sketch of the sky at a given moment in time

Description

Create a simplistic sketch of the sky at a given moment in time

Usage

sky.sketch(
  time,
  timezone,
  calendar,
  xrange = c(30, 150),
  yrange = c(-45, 45),
  sun = T,
  moon = T,
  planets = F,
  exagerate = T,
  max.mag = 6,
  loc,
  atm,
  temp
)

Arguments

Examples

sky.sketch(time='2019/01/10 18:51', loc=c(35,-8,100))

See and change the global variables used by skyscapeR

Description

See and change the global variables used by skyscapeR

Usage

skyscapeR.vars(timezone, calendar, refraction, atm, temp, dec)

Arguments

Examples

# Julian date at noon GMT on Christmas day 2018
time2jd('2018-12-25 12:00:00', 'GMT')

Declination of southern minor Lunar Extreme for a given year

Description

This function calculates the declination of the southern minor Lunar Extreme for a given year, based upon obliquity estimation and corrected average parallax.

Usage

smnLX(
  year = skyscapeR.env$cur.year,
  loc = FALSE,
  parallax = 0.952,
  altitude = 0,
  verbose = TRUE
)

Arguments

See Also

nmnLX, nMjLX, sMjLX, parallax.corr

Examples

# Southern minor Lunar Extreme geocentric declination for year 2501 BC:
smnLX(-2500)

# Topocentric declination for same year and latitude of 50 degrees N:
smnLX(-2500, loc=50)

Solar Date

Description

Returns the calendar date when the sun has the same declination as the input declination.

Usage

solar.date(dec, year, calendar, verbose = T)

Arguments

Examples

solar.date(-23, 2018)
solar.date(-12, 1200, calendar='G')
solar.date(-12, 1200, calendar='J')
solar.date(14, -2000)

Declination of the spatial equinox for a given location

Description

Declination of the spatial equinox for a given location

Usage

spatial.equinox(hor, parallax = 0.00224)

Arguments

See Also

jS, dS, eq, zenith, antizenith, parallax.corr

Examples

## Not run: 
hor <- createHWT(34.174051531543405, 110.81299818694872, name='Xipo, Lingbao')
spatial.equinox(hor)

## End(Not run)

Summed probability density (SPD)

Description

Summed probability density (SPD)

Usage

spd(pdf, normalise = F, xrange, .cutoff = 1e-05, .res = 0.01)

Arguments

References

Silva, F (2020) A probabilistic framework and significance test for the analysis of structural orientations in skyscape archaeology Journal of Archaeological Science 118, 105138. <doi:10.1016/j.jas.2020.105138>

Examples

# SPD of azimuths
Az <- az.pdf(az=c(87,93,90,110), unc=3)
s1 <- spd(Az)
plot(s1)

# SPD of declinations
hor <- createHor(az=c(0,360), alt=c(0,0), loc=c(35,-8,25)) # flat horizon with 0 degrees of altitude
Dec <- coordtrans(Az, hor)
s2 <- spd(Dec)
plot(s2)

Create skyscapeR.star object

Description

This function retrieves information for a given star and saves it in the skyscapeR.star format ready to be used by other skyscapeR package function.

Usage

star(string, year = skyscapeR.env$cur.year)

Arguments

See Also

swe_fixstar2_ut, swe_fixstar2_mag

Examples

# Retrieve data for Aldebaran:
Aldeb <- star('Aldebaran')

# Retrieve data for Aldebaran on 2999 BC:
ss <- star('Aldebaran', -3000)

Calculate the seasons and phase type of a star

Description

This function calculates the seasons (Rising, Setting, etc.) and phase types (Arising and Lying Hidden, Curtailed Passage) of a star for a given location and epoch. This functions uses the arcus visionis approximation of Purrington (1988) and the atmospheric extinction approximation of Schaefer (1989). For the nomenclature used, and description of star phase types, see Brady (2015).

Usage

star.phases(
  star,
  year,
  loc,
  alt.hor = 0,
  k = 0.2,
  limit = 6,
  alt.rs = 10,
  res = 1/24/6,
  refraction,
  atm,
  temp
)

Arguments

References

Purrington, Robert D. (1988) Heliacal Rising and Setting: Quantitative Aspects, Journal for the History of Astronomy (Archaeoastronomy Supplement 12) 19, S72-S84. Available online at [SAO/NASA ADS Astronomy Abstract Service](http://adsabs.harvard.edu/abs/1988JHAS...19...72P)

Brady, Bernadette (2015) Star Phases: the Naked-eye Astronomy of the Old Kingdom Pyramid Texts. In F Silva and N Campion (eds) Skyscapes: The Role and Importance of the Sky in Archaeology. Oxford: Oxbow Books, pp. 76-86.

See Also

plot.skyscapeR.starphases

Examples

## Not run: 
ss1 <- star.phases('Aldebaran',-4000, c(35,-8,200))

# One can then look at the star's phase type:
ss1$metadata$type

# Date range of seasons:
ss1$metadata$seasons

# Date range of phase-type events:
ss1$metadata$events

# And plot them:
plot(ss1)

# You can play with the parameters and see how predictions change:
ss1 <- star.phases('Aldebaran',-4000, c(35,-8,200), alt.hor=2, alt.rs=5)
plot(ss1)

## End(Not run)

Returns the azimuth of the sun at a given time from a specific location

Description

This function returns the azimuth of the sun at a given time and location, useful for data reduction of theodolite measurements using the sun-sight technique (reduct.theodolite).

Usage

sunAz(loc, time, timezone, limb, alt = F)

Arguments

See Also

reduct.theodolite

Examples

sunAz(c(52,-3,100), '2017-10-04 12:32:14', 'Europe/London')

Converts degree measurements in deg-min-sec (º ' ") format into decimal-point degree format.

Description

Converts degree measurements in deg-min-sec (º ' ") format into decimal-point degree format.

Usage

ten(dd, mm = 0, ss = 0)

Arguments

Examples

deg <- ten(24, 52, 16)

Converts date and time (in any timezone) to Julian date

Description

Converts date and time (in any timezone) to Julian date

Usage

time2jd(time, timezone, calendar, verbose = F)

Arguments

See Also

swe_julday, as.POSIXlt, timezones, timestring

Examples

# Julian date at noon GMT on Christmas day 2018
time2jd('2018/12/25 12:00:00', 'GMT')

Converts date and time numeric values to a single string

Description

Converts date and time numeric values to a single string

Usage

timestring(year, month, day, hour = 12, minute = 0, second = 0)

Arguments

Examples

timestring(2018, 12, 25, 2, 34)

Declination of the zenith sun for a given location

Description

This function returns the declination of the sun when it is at the zenith for a given location with corrected average parallax. If this phenomena does not occur at given location (i.e. if location is outside the tropical band) the function returns a NULL value.

Usage

zenith(loc, parallax = 0.00224, altitude = 0)

Arguments

See Also

jS, dS, eq, antizenith, spatial.equinox, parallax.corr

Examples

# Zenith sun declination for Mexico City:
zenith(19.419)

# There is no zenith sun phenomenon in London:
zenith(51.507)