Deutsch: Plot von ∆T = TT − UT für die Jahre 1657–2023,000, wo TT die de:Terrestrische Zeit and UT die de:Universal Time ist. Er kombiniert Daten aus historic_deltat.data (1657 – 1973,000) und deltat.data (1973-02-01 – 2023-01-01). Die Werte bis 1973 stammen aus einer Arbeit von McCarthy und Babcock von 1986 (s. readme).
English: Plot of ∆T = TT − UT for the years 1657–2023.000, where TT is en:Terrestrial Time and UT is en:Universal Time. It combines data from historic_deltat.data (1657 – 1973.000) and deltat.data (1973-02-01 – 2023-01-01). The values until 1973 are from a paper of McCarthy and Babcock from 1986 (cf. readme).
#!/bin/sh# Generate file hist.data (with columns year and ΔT).# Get data from web
wgethttps://maia.usno.navy.mil/ser7/historic_deltat.data# 1657.0 - 1984.5
wgethttps://maia.usno.navy.mil/ser7/deltat.data# 1973-02-01 onward# Prepare data for 1657.000 to 1973.000
awk' BEGIN { getline; getline; } { print $1 "\t" $2; } $1 == 1973 { exit; }'<historic_deltat.data>hist.data
# Append data for 1973-02-01 to 2023-01-01
awk' { "date +%j --date=" $1 "-" $2 "-" $3 |getline day; # 001, …, 366 "date +%j --date=" $1 "-12-31" |getline yLen; # 365 or 366 printf("%0.3f\t%s\n", $1 + ((day - 1)/yLen), $4); } $1 == 2023 { exit; }'<deltat.data>>hist.data
Gnuplot code
#!/usr/bin/env gnuplot# Plot data from hist.data.setterminalsvgsize640,480name"Delta_T"setoutput'Delta_T_1657-2022.svg'settitle"∆T = TT − UT"setxlabel"year"setylabel"∆T/s"setgridlinetype1linecolorrgb"#cccccc"unsetkeysetstyledatalinessetstyleline1linetype1linewidth2setstyleincrementusersetxzeroaxislinetype2linecolorrgb"black"plot'hist.data'linetypergb"#FF0000"