id stringlengths 16 145 | text stringlengths 1 179k | title stringclasses 1
value |
|---|---|---|
astropy_Time/astropy_Time_36_0.txt | reshape ( _ * args _ , _ ** kwargs _ ) #
Returns an instance containing the same data with a new shape.
Parameters are as for [ ` reshape() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.reshape.html#numpy.ndarray.reshape
"\(in NumPy v1.26\)") . Note that it is not always possible to... | |
astropy_Time/time.html7_55_0.txt | ## Setting a Custom Value For ∆T ¶
If you ever want to specify your own value for ∆T, then provide a ` delta_t `
keyword argument when creating your timescale: | |
astropy_Time/internet-time-service-its3_18_0.txt | Email
## Set your computer clock via the Internet using tools built into the
operating system | |
astropy_Time/astropy_Time_17_0.txt | scale #
Time scale.
| |
astropy_Time/deltaut1.html2_14_0.txt | ` DUT1=deltaUT1(utc) `
` [DUT1,DUT1Error]=deltaUT1(utc) ` | |
astropy_Time/astropy_Time_23_0.txt | argmax ( _ axis = None _ , _ out = None _ ) #
Return indices of the maximum values along the given axis.
This is similar to [ ` argmax() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.argmax.html#numpy.ndarray.argmax
"\(in NumPy v1.26\)") , but adapted to ensure that the full preci... | |
astropy_Time/deltaut1.html2_34_0.txt | ## Output Arguments
collapse all | |
astropy_Time/internet-time-service-its3_19_0.txt | * * *
NIST has established a mailing list (Google Group) to inform users of status
changes of the Internet Time Service. If you wish to subscribe to this list,
please send your name and email address to: internet-time-service [at]
nist.gov (subject: Subscribe%20to%20ITS%20mailing%20list) (internet-time-
service[at... | |
astropy_Time/astropy_Time_19_0.txt | size #
The size of the object, as calculated from its shape.
| |
astropy_Time/deltaut1.html2_51_0.txt | * Australia (English)
* India (English)
* New Zealand (English)
* 中国
* 简体中文
* English
* 日本 (日本語)
* 한국 (한국어)
Contact your local office | |
astropy_Time/deltaut1.html2_19_0.txt | ` ` DUT1 ` =deltaUT1( ` utc ` , ` Name,Value ` ) ` calculates the difference
between UTC and UT1 using additional options specified by one or more `
Name,Value ` pair arguments.
` [ ` DUT1 ` , ` DUT1Error ` ]=deltaUT1( ` utc ` , ` Name,Value ` ) `
returns the error for the difference between Coordinated Universa... | |
astropy_Time/time.html7_20_0.txt | ## UTC and leap seconds ¶
The rate of Earth’s rotation is gradually slowing down. Since the UTC standard
specifies a fixed length for the second, promises a day of 24 hours, and
limits an hour to 60 minutes, the only way to stay within the rules while
keeping UTC synchronized with the Earth is to occasionally add an... | |
astropy_Time/astropy_Time_11_0.txt | jd2 #
Second of the two doubles that internally store time value(s) in JD.
| |
astropy_Time/time.html7_48_0.txt | Skyfield relies on the IERS, the International Earth Rotation Service, for
accurate measurements of UT1 and for the schedule of leap seconds (discussed
above) that keeps UTC from straying more than 0.9 seconds away from UT1.
Each new version of Skyfield carries recent IERS data in internal tables. This
data will gradu... | |
astropy_Time/deltaut1.html2_13_0.txt | collapse all in page
## Syntax | |
astropy_Time/time.html7_40_0.txt | ## Uniform time scales: TAI, TT, and TDB ¶
Date arithmetic becomes very simple as we leave UTC behind and consider
completely uniform time scales. Days are always 24 hours, hours always 60
minutes, and minutes always 60 seconds without any variation or exceptions.
Such time scales are not appropriate for your mornin... | |
astropy_Time/deltaut1.html2_4_0.txt | * Help Center
* MathWorks
Search MathWorks.com | |
astropy_Time/internet-time-service-its3_2_0.txt | Official websites use .gov
A .gov website belongs to an official government organization in the United
States.
Secure .gov websites use HTTPS
A lock ( Lock A locked padlock ) or https:// means you’ve safely
connected to the .gov website. Share sensitive information only on official,
secure websites. | |
astropy_Time/deltaut1.html2_26_0.txt | collapse all
### ` utc ` — Principal Universal Time (UT1) for UTC
M -by-1 array | |
astropy_Time/time.html7_41_0.txt | Because they make every day the same length, uniform time scales can express
dates as a simple floating-point count of days elapsed. To make all historical
dates come out as positive numbers, astronomers traditionally assign each date
a “Julian day” number that starts counting at 4713 BC January 1 in the old
Julian cal... | |
astropy_Time/deltaut1.html2_10_0.txt | * Trial Software
* Trial Software
* Product Updates
* Product Updates
Resources | |
astropy_Time/time.html7_37_0.txt | Finally, converting an array ` Time ` back into a calendar tuple results in
the year, month, day, hour, minute, and second each having the same dimension
as the array itself:
print(t.utc)
[[2014. 2014. 2014. 2014.]
[ 1. 1. 1. 1.]
[ 1. 2. 3. 4.]
[ ... | |
astropy_Time/time.html7_15_0.txt | * Every version of Python that Skyfield supports will work with the pytz package described in this section.
* Python 3.6 upgraded the Standard Library ` datetime ` type so that the contortions of pytz are no longer necessary, and instead recommends dateutil for working with timezones. Consult its documentat... | |
astropy_Time/deltaut1.html2_49_0.txt | ### Europe
* Belgium (English)
* Denmark (English)
* Deutschland (Deutsch)
* España (Español)
* Finland (English)
* France (Français)
* Ireland (English)
* Italia (Italiano)
* Luxembourg (English) | |
astropy_Time/internet-time-service-its3_45_0.txt | Created February 10, 2010, Updated October 3, 2023
### HEADQUARTERS | |
astropy_Time/deltaut1.html2_38_0.txt | expand all
### R2020b: Updated ` aeroiersdata.mat ` file | |
astropy_Time/deltaut1.html2_45_0.txt | Choose a web site to get translated content where available and see local
events and offers. Based on your location, we recommend that you select: .
* Switzerland (English)
* Switzerland (Deutsch)
* Switzerland (Français) | |
astropy_Time/astropy_Time_32_0.txt | max ( _ axis = None _ , _ out = None _ , _ keepdims = False _ ) #
Maximum along a given axis.
This is similar to [ ` max() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.max.html#numpy.ndarray.max
"\(in NumPy v1.26\)") , but adapted to ensure that the full precision given by
the... | |
astropy_Time/astropy_Time_4_0.txt | delta_tdb_tt #
TDB - TT time scale offset
| |
astropy_Time/time.html7_12_0.txt | The 6 values returned by ` utc() ` can be accessed as the attributes ` year
` , ` month ` , ` day ` , ` hour ` , ` minute ` , and ` second ` .
print(t1.utc.year, '/', t1.utc.month, '/', t1.utc.day)
print(t1.utc.hour, ':', t1.utc.minute, ':', t1.utc.second)
2014 / 1 / 18
1... | |
astropy_Time/time.html7_51_0.txt | Note that the international agencies responsible for the file’s distribution
sometimes have trouble keeping their servers up. For example, as I write this
in May of 2022, the file cannot be fetched from ` ftp.iers.org ` because of
an Outage of iers.org data servers reported on their website. At Skyfield
issue #730 ... | |
astropy_Time/deltaut1.html2_5_0.txt | MathWorks
* MathWorks
* Help Center | |
astropy_Time/internet-time-service-its3_0_0.txt | Skip to main content
An official website of the United States government | |
astropy_Time/time.html7_8_0.txt | You are free to choose your own cutoff Julian day if you are studying
astronomy records from a country that adopted the Gregorian calendar on some
other date. Russia, for example, did not adopt it until the twentieth century.
The default value, that asks the timescale to always use Gregorian dates, is `
None ` :
... | |
astropy_Time/internet-time-service-its3_16_0.txt | ## Share
Facebook | |
astropy_Time/astropy_Time_18_0.txt | shape #
The shape of the time instances.
Like [ ` shape `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.shape.html#numpy.ndarray.shape
"\(in NumPy v1.26\)") , can be set to a new shape by assigning a tuple. Note
that if different instances share some but not all underlying data, setting
the... | |
astropy_Time/time.html7_29_0.txt | ## Date arrays ¶
If you want to ask where a planet or satellite was across a whole series of
times and dates, then Skyfield will work most efficiently if, instead of
building many separate ` Time ` objects, you build a single ` Time `
object that holds the entire array of dates. | |
astropy_Time/item_list.htm4_4_0.txt | Universal Time (UT) and Greenwich Mean Time (GMT)
UT0 | |
astropy_Time/internet-time-service-its3_34_0.txt | The time information provided by the service is directly traceable to
UTC(NIST). The service responds to time requests from any Internet client in
several formats including the DAYTIME, TIME, and NTP protocols.
Requests in these formats generally do not support authentication, and no keys
or passwords are needed to us... | |
astropy_Time/item_list.htm4_7_0.txt | With further improvements in the precision of clocks, it was discovered that
UT1 had periodic variations caused by the seasonal fluctuation in the rate of
rotation of the earth. Corrections were made to remove this effect and an even
more uniform time UT2 was obtained.
International Atomic Time (TAI) | |
astropy_Time/time.html7_61_0.txt | You will typically never need to access these matrices yourself, as they are
used automatically by the ` radec() ` method when you use its ` epoch= `
parameter to ask for a right ascension and declination in the dynamical
reference system, and when you ask a ` GeographicPosition ` object for its
position.
| |
astropy_Time/internet-time-service-its3_44_0.txt | * Internet Time Service
internet-time-service@nist.gov | |
astropy_Time/internet-time-service-its3_8_0.txt | * User Facilities
* NIST Center for Neutron Research
* CNST NanoFab
* Research Test Beds
* Research Projects
* Tools & Instruments
* Major Programs
* Baldrige Performance Excellence Program
* CHIPS for America Initiative
* Manufacturing Extension Partnership (... | |
astropy_Time/time.html7_36_0.txt | You can combine a Python ` for ` loop with Python’s ` zip() ` builtin to
print each time alongside the corresponding coordinates. There are two
techniques, one of which is less efficient and the other more efficient.
# Less efficient: loop over `t`, forcing the creation of
# a separate `Time` objec... | |
astropy_Time/deltaut1.html2_35_0.txt | ### ` DUT1 ` — Difference between UT1 and UTC
M -by-1 array
Difference between UT1 and UTC, specified as an M -by-1 array. | |
astropy_Time/time.html7_17_0.txt |
from datetime import datetime
from pytz import timezone
eastern = timezone('US/Eastern')
# Converting US Eastern Time to a Skyfield Time.
d = datetime(2014, 1, 16, 1, 32, 9)
e = eastern.localize(d)
t = ts.from_datetime(e)
When Skyfield returns a ` Time ` at t... | |
astropy_Time/time.html7_47_0.txt | Finally, UT1 is the least uniform time scale of all because its clock cannot
be housed in a laboratory, nor is its rate established by any human
convention. It is, rather, the clock whose “hand” is the rotation of the Earth
itself! The direction that the Earth is facing determines not only the
coordinates of every city... | |
astropy_Time/internet-time-service-its3_9_0.txt | * Services & Resources
* Standards and Measurements
* Calibration Services
* Laboratory Accreditation (NVLAP)
* Quality System
* Standard Reference Materials (SRMs)
* Standard Reference Instruments (SRIs)
* Standards.gov
* Time Services
* Office of Weights... | |
astropy_Time/deltaut1.html2_50_0.txt | * Netherlands (English)
* Norway (English)
* Österreich (Deutsch)
* Portugal (English)
* Sweden (English)
* Switzerland
* Deutsch
* English
* Français
* United Kingdom (English)
### Asia Pacific | |
astropy_Time/time.html7_33_0.txt | When you provide a time array as input to a Skyfield calculation, the output
array will have an extra dimension that expands what would normally be a
single result into as many results as you provided dates. We can compute the
position of the Earth as an example:
# Single Earth position
planets ... | |
astropy_Time/time.html7_4_0.txt | * Time scales
* Time objects
## Ancient and modern dates ¶ | |
astropy_Time/astropy_Time_40_0.txt | swapaxes ( _ * args _ , _ ** kwargs _ ) #
Return an instance with the given axes interchanged.
Parameters are as for [ ` swapaxes() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.swapaxes.html#numpy.ndarray.swapaxes
"\(in NumPy v1.26\)") : ` axis1, axis2 ` . All internal data are v... | |
astropy_Time/item_list.htm4_11_0.txt | The Gregorian calendar, which is currently used in most countries of the
world, was derived from the Julian calendar. In the Julian calendar, a mean
length of 365.25 days for the year is adopted. The calendar year is adjusted
to this mean value by inserting an intercalary day every four years. The
intercalary or leap y... | |
astropy_Time/deltaut1.html2_15_0.txt | ` DUT1=deltaUT1(utc,Name,Value) `
` [DUT1,DUT1Error]=deltaUT1(utc,Name,Value) ` | |
astropy_Time/internet-time-service-its3_25_0.txt | NIST operates several stratum-1 network time servers, which means their time
is directly linked to UTC(NIST), the official NIST time. Other sources of time
are not monitored or certified by NIST.
Here are the server names, locations, and IP addresses and current status .
There are some steps you may have to tak... | |
astropy_Time/astropy_Time_27_0.txt | diagonal ( _ * args _ , _ ** kwargs _ ) #
Return an instance with the specified diagonals.
Parameters are as for [ ` diagonal() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.diagonal.html#numpy.ndarray.diagonal
"\(in NumPy v1.26\)") . All internal data are views of the data of the
o... | |
astropy_Time/internet-time-service-its3_31_0.txt | The message formats do not contain any information about how the leap second
event is realized by a time server, so that it is difficult to combine data
from different sources close to a leap second event. In addition, users who
require time stamps that are traceable to national or international standards
must be aware... | |
astropy_Time/item_list.htm4_6_0.txt | There are two refinements of UT0 called UT1 and UT2. As better clocks were
developed, astronomers began to notice a discrepancy in UT0 measured at
different locations. This was later found caused by a wobble in the axis of
the earth. After careful measurements at various observatories throughout the
world, the effect o... | |
astropy_Time/deltaut1.html2_6_0.txt | Close Mobile Search
Open Mobile Search | |
astropy_Time/deltaut1.html2_37_0.txt | ## Version History
Introduced in R2017b | |
astropy_Time/internet-time-service-its3_4_0.txt | Menu
Close | |
astropy_Time/astropy_Time_14_0.txt | ndim #
The number of dimensions of the instance and underlying arrays.
| |
astropy_Time/time.html7_18_0.txt |
# UTC datetime
dt = t.utc_datetime()
print('UTC: ' + str(dt))
# Converting back to an Eastern Time datetime.
dt = t.astimezone(eastern)
print('EST: ' + str(dt))
UTC: 2014-01-16 06:32:09+00:00
EST: 2014-01-16 01:32:09-05:00
As we would expect,... | |
astropy_Time/deltaut1.html2_29_0.txt | Example: 'Source','aeroiersdata.mat'
### ` Source ` — Custom list of Earth orientation data
` aeroiersdata.mat ` (default) | MAT-file | |
astropy_Time/astropy_Time_2_0.txt | T #
Return an instance with the data transposed.
Parameters are as for [ ` T `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.T.html#numpy.ndarray.T
"\(in NumPy v1.26\)") . All internal data are views of the data of the
original.
| |
astropy_Time/time.html7_52_0.txt |
if load.days_old('finals2000A.all') > 30.0:
load.download('finals2000A.all')
ts = load.timescale(builtin=False)
But, beware! For compatibility with versions of Skyfield ≤ 1.30, Skyfield will
ignore ` finals2000A.all ` if the three old files ` deltat.data ` , `
deltat.preds ` , an... | |
astropy_Time/astropy_Time_20_0.txt | unmasked #
Get an instance without the mask.
Note that while one gets a new instance, the underlying data will be shared.
See also
` astropy.time.Time.filled `
| |
astropy_Time/time.html7_53_0.txt | If you ever want to display or plot the behavior of UT1, astronomers use two
common conventions for stating the difference between clock time and UT1.
Skyfield supports them both.
print('{:+.4f}'.format(t.dut1))
print('{:+.4f}'.format(t.delta_t))
-0.0970
+67.2810
| |
astropy_Time/deltaut1.html2_22_0.txt |
mjd = mjuliandate(2015,12,28)
dUT1 = deltaUT1(mjd)
mjd =
57384
dUT1 =
0.0886
### Calculate Difference Value for December 28, 2015 and January 10, 2016 | |
astropy_Time/deltaut1.html2_21_0.txt | ### Calculate Difference Value for December 28, 2015
Calculate the difference between UT1 and UTC values for December 28, 2015. | |
astropy_Time/time.html7_14_0.txt | ## UTC and your timezone ¶
To move beyond UTC and work with other world timezones, you will need to
install a time zone database for your version of Python. | |
astropy_Time/time.html7_0_0.txt | Skyfield: Home • Table of Contents • Changelog • API Reference
# Dates and Time ¶ | |
astropy_Time/time.html7_28_0.txt |
from datetime import timedelta
t - 10 # 10 days earlier
t + 0.25 # 6 hours later
t + timedelta(hours=12) # 12 hours later
t2 - t1 # difference between times, in days
Raw numbers, like ` 10 ` and ` 0.25 ` above, specify days of Terrestri... | |
astropy_Time/internet-time-service-its3_43_0.txt | ## Contacts
### For questions or more information about the NIST Internet Time Service,
contact Judah Levine. | |
astropy_Time/item_list.htm4_16_0.txt | Julian Day Number is a count of days elapsed since Greenwich mean noon on 1
January 4713 B.C. The Julian Date is the Julian day number followed by the
fraction of the day elapsed since the preceding noon. Modified Julian Date
(MJD) is defined as: MJD=JD-2400000.5
Julian Date (JD) and Modified Julian Date (MJD) | |
astropy_Time/deltaut1.html2_18_0.txt | ` [ ` DUT1 ` , ` DUT1Error ` ]=deltaUT1( ` utc ` ) ` returns the error for
the difference between Coordinated Universal Time (UTC) and Principal
Universal Time (UT1) for UTC.
example | |
astropy_Time/time.html7_54_0.txt | The two quantities are:
* DUT1 — The difference between UTC and UT1, which should always be less than 0.9 if the IERS succeeds at its mission. Note that there are two different reasons that this value changes: every day it changes a small amount because of the drift of UT1; and superimposed on this drift is a big ju... | |
astropy_Time/time.html7_45_0.txt | Terrestrial Time (TT) differs from TAI only because astronomers were already
maintaining a uniform time scale of their own before TAI was established,
using a slightly different starting point for the day. For practical purposes,
TT is simply TAI plus exactly 32.184 seconds. So it is now more than a minute
ahead of UTC... | |
astropy_Time/deltaut1.html2_9_0.txt | * deltaUT1
* On this page
* Syntax
* Description
* Examples
* Calculate Difference Value for December 28, 2015
* Calculate Difference Value for December 28, 2015 and January 10, 2016
* Calculate Difference Value and Error Using IERS Data
* Input Arguments
* utc
* Name-Value Arg... | |
astropy_Time/deltaut1.html2_23_0.txt | Calculate the difference between UT1 and UTC values for December 28, 2015 and
January 10, 2016 using the custom file, aeroiersdata20170101.mat.
mjd = mjuliandate([2015 12 28;2016 1 10])
dUT1 = deltaUT1(mjd,'Source','aeroiersdata20170101.mat')
mjd =
57384
57397
... | |
astropy_Time/time.html7_30_0.txt | There are three techniques for building a ` Time ` array.
* Provide ` tai() ` or ` tt() ` or ` tdb() ` or ` ut1() ` with a Python list or NumPy array of numbers for one of the six components of the calendar date (year, month, day, hour, minute, or second).
* Provide ` tai_jd() ` or ` tt_jd() ` or `... | |
astropy_Time/deltaut1.html2_39_0.txt | The contents of the ` aeroiersdata.mat ` file have been updated.
Correspondingly, the output of this function will have different results when
using the default value ( ` 'aeroiersdata.mat' ` ) as the value of ` Source `
. The results reflect more accurate external data from the International Earth
Rotation and Referen... | |
astropy_Time/item_list.htm4_10_0.txt | Leap Year
Gregorian calendar | |
astropy_Time/deltaut1.html2_12_0.txt | # deltaUT1
Calculate difference between Coordinated Universal Time (UTC) and Principal
Universal Time (UT1) | |
astropy_Time/time.html7_9_0.txt | Note that even the Julian calendar becomes anachronistic before its adoption
in 45 BC, so all dates generated by Skyfield are “proleptic” before that date.
And, of course, the Julian calendar was local to the civilization that ringed
the Mediterranean. If you are interested in relating astronomical events to
more ancie... | |
astropy_Time/item_list.htm4_1_0.txt | # Basic Terms of Time Services
# Basic Terms of Time Services | |
astropy_Time/astropy_Time_24_0.txt | argmin ( _ axis = None _ , _ out = None _ ) #
Return indices of the minimum values along the given axis.
This is similar to [ ` argmin() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.argmin.html#numpy.ndarray.argmin
"\(in NumPy v1.26\)") , but adapted to ensure that the full preci... | |
astropy_Time/astropy_Time_35_0.txt | ravel ( _ * args _ , _ ** kwargs _ ) #
Return an instance with the array collapsed into one dimension.
Parameters are as for [ ` ravel() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.ravel.html#numpy.ndarray.ravel
"\(in NumPy v1.26\)") . Note that it is not always possible to unrave... | |
astropy_Time/astropy_Time_21_0.txt | value #
Time value(s) in current format.
| |
astropy_Time/internet-time-service-its3_28_0.txt | For more detailed information about leap seconds, see Leap Seconds FAQs .
The name of a positive leap second is 23:59:60, but digital time formats,
which represent the current time as the number of seconds that have elapsed
since some origin (NTP, for example), cannot represent that time. The NIST
time servers add t... | |
astropy_Time/time.html7_43_0.txt | More than two million days have passed since 4714 BC, so modern dates tend to
be rather large numbers:
# 2014 January 1 00:00 UTC expressed as Julian dates
t = ts.utc(2014, 1, 1)
print('TAI = %r' % t.tai)
print('TT = %r' % t.tt)
print('TDB = %r' % t.tdb)
TAI = 245... | |
astropy_Time/astropy_Time_41_0.txt | 'raise' _ ) #
Return a new instance formed from the elements at the given indices.
Parameters are as for [ ` take() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.take.html#numpy.ndarray.take
"\(in NumPy v1.26\)") , except that, obviously, no output array can be given.
to_datetime ( _ ... | |
astropy_Time/time.html7_6_0.txt | If you would like Skyfield to switch to the Julian calendar for historical
dates — both when interpreting the dates you input, and when producing
calendar dates as output — simply give your ` Timescale ` object the Julian
day on which you would like the calendar to switch.
from skyfield.api import GRE... | |
astropy_Time/astropy_Time_1_1.txt | ttps://docs.python.org/3/library/stdtypes.html#bltin-
boolean-values "\(in Python v3.12\)") , optional
Make a copy of the input values
Attributes Summary
` FORMATS ` | Dict of time formats
---|---
` SCALES ` | List of time scales
` T ` | Return an instance with the data transposed.
` cache ` ... | |
astropy_Time/deltaut1.html2_17_0.txt | ` ` DUT1 ` =deltaUT1( ` utc ` ) ` calculates the difference between
Coordinated Universal Time (UTC) and Principal Universal Time (UT1) for UTC,
specified as a modified Julian date (MJD). By default, this function uses a
prepopulated list of International Astronomical Union (IAU) 2000A Earth
orientation (IERS) data. T... | |
astropy_Time/deltaut1.html2_24_0.txt | ### Calculate Difference Value and Error Using IERS Data
Calculate the difference between UT1-UTC values for December 28, 2015 and
January 10, 2016 using the custom file, ` aeroiersdata.mat ` . | |
astropy_Time/time.html7_2_0.txt | The ` Timescale ` object returned by ` load.timescale() ` manages the
conversions between different time scales and is also how the programmer
builds ` Time ` objects for specific dates. Most applications create only
one ` Timescale ` object, which Skyfield programmers conventionally name `
ts ` , and use it to... | |
astropy_Time/time.html7_58_0.txt | In addition to time scales, each ` Time ` object caches several other
quantities that are often needed in astronomy. Skyfield only computes these
attributes on-demand, the first time the user tries to access them or invokes
a computation that needs their value:
` gmst ` | |
astropy_Time/time.html7_34_0.txt | Note the shape of the resulting NumPy array. If you unpack this array into
three names, then you get three four-element arrays corresponding to the four
dates. These four-element arrays are ready to be submitted to matplotlib and
other scientific Python tools:
x, y, z = pos # four values each
pl... | |
astropy_Time/astropy_Time_5_0.txt | delta_ut1_utc #
UT1 - UTC time scale offset
|
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