id stringlengths 16 145 | text stringlengths 1 179k | title stringclasses 1
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|---|---|---|
astropy_Time/internet-time-service-its3_14_0.txt | Physical Measurement Laboratory / Time and Frequency Division
## Time Realization and Distribution Group | |
astropy_Time/time.html7_1_0.txt | Astronomers use a variety of different scales to measure time. Skyfield often
has to use several timescales within a single computation! The ` Time `
class is how Skyfield represents either a single moment in time or a whole
array of moments, and keeps track of all of the different designations
assigned to that momen... | |
astropy_Time/item_list.htm4_14_0.txt | Since the first leap second in 1972, all leap seconds have been positive.
Click here for the historical list of leap second. | |
astropy_Time/time.html7_5_0.txt | Skyfield normally uses the modern Gregorian calendar, even for dates in
history before the Gregorian calendar’s adoption in 1582. This “proleptic” use
of Gregorian dates makes date calculations simple, is compatible with Python’s
` datetime ` , and is also the behavior of the United States Naval
Observatory library on... | |
astropy_Time/astropy_Time_34_0.txt | ptp ( _ axis = None _ , _ out = None _ , _ keepdims = False _ ) #
Peak to peak (maximum - minimum) along a given axis.
This is similar to [ ` ptp() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.ptp.html#numpy.ndarray.ptp
"\(in NumPy v1.26\)") , but adapted to ensure that the fu... | |
astropy_Time/deltaut1.html2_3_0.txt | Search Help Center
Help Center | |
astropy_Time/item_list.htm4_17_0.txt | MJD
Local Time | |
astropy_Time/internet-time-service-its3_27_0.txt | * * *
### The Internet Time Service and Leap Seconds | |
astropy_Time/deltaut1.html2_46_0.txt | * 中国 (简体中文)
* 中国 (English)
You can also select a web site from the following list: | |
astropy_Time/deltaut1.html2_47_0.txt | ## How to Get Best Site Performance
Select the China site (in Chinese or English) for best site performance. Other
MathWorks country sites are not optimized for visits from your location. | |
astropy_Time/time.html7_31_0.txt | The first possibility is generally the one that is the most fun, because its
lets you vary whichever time unit you want while holding the others constant.
You are free to provide out-of-range values and leave it to Skyfield to work
out the correct result. Here are some examples:
ts.utc(range(1900, 1950))... | |
astropy_Time/item_list.htm4_0_0.txt | Skip Content
# Basic Terms of Time Services | |
astropy_Time/internet-time-service-its3_42_0.txt | The time format has poor error-handling capabilities because any 32-bit value
could be a correct response. Many of the client programs that use this format
are poorly written and may not handle network errors properly. Therefore,
users are strongly encouraged to switch to the Network Time Protocol (NTP),
which is more ... | |
astropy_Time/astropy_Time_0_0.txt | Skip to main content
__ Back to top
__ ` Ctrl ` \+ ` K `
[  ](../index.html)
* [ Getting Started ](../index_getting_started.html)
* [ User Guide ](../index_user_docs.html)
* [ Development ](../index_dev.html)
* [ Project Details ](../index_project_de... | |
astropy_Time/deltaut1.html2_48_0.txt | ### Americas
* América Latina (Español)
* Canada (English)
* United States (English) | |
astropy_Time/deltaut1.html2_42_0.txt | ## MATLAB Command
You clicked a link that corresponds to this MATLAB command: | |
astropy_Time/deltaut1.html2_52_0.txt | * Trial Software
* Trial Software
* Product Updates
* Product Updates
* United States | |
astropy_Time/astropy_Time_25_0.txt | argsort ( _ axis = -1 _ , _ kind = 'stable' _ ) #
Returns the indices that would sort the time array.
This is similar to [ ` argsort() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.argsort.html#numpy.ndarray.argsort
"\(in NumPy v1.26\)") , but adapted to ensure that the full preci... | |
astropy_Time/time.html7_39_0.txt | Slicing in the other direction, the rows can be fetched not only by index but
also through the attribute names ` year ` , ` month ` , ` day ` , ` hour `
, ` minute ` , and ` second ` .
print(t.utc.year)
print(t.utc.month)
print(t.utc.day)
print(t.utc.hour)
[2014. 2014... | |
astropy_Time/deltaut1.html2_2_0.txt | * Get MATLAB
Help Center Help Center | |
astropy_Time/item_list.htm4_19_0.txt | Click here for the International Time Zone Map
| |
astropy_Time/astropy_Time_3_0.txt | cache #
Return the cache associated with this instance.
| |
astropy_Time/deltaut1.html2_1_0.txt | * Products
* Solutions
* Academia
* Support
* Community
* Events
* Get MATLAB
* Products
* Solutions
* Academia
* Support
* Community
* Events | |
astropy_Time/internet-time-service-its3_23_0.txt | Manually setting the system clock:
* * * | |
astropy_Time/internet-time-service-its3_33_0.txt | Questions or comments: Judah Levine Time and Frequency Division NIST Boulder
Judah.Levine [at] nist.gov (Judah[dot]Levine[at]nist[dot]gov)
### Protocols and Authentication | |
astropy_Time/time.html7_11_0.txt | Feel free to use fractional days, hours, and minutes. Here are several ways to
specify the exact same time and date:
# Four ways to specify 2014 January 18 01:35:37.5
t1 = ts.utc(2014, 1, 18.06640625)
t2 = ts.utc(2014, 1, 18, 1.59375)
t3 = ts.utc(2014, 1, 18, 1, 35.625)
t4 = ts.utc(2... | |
astropy_Time/deltaut1.html2_32_0.txt | * Warning — Displays warning and indicates that the dates were out-of-range or predicted values.
* Error — Displays error and indicates that the dates were out-of-range or predicted values. | |
astropy_Time/item_list.htm4_5_0.txt | Since the earth's orbit around the sun is not a perfect circle and its speed
changes with its distance from the sun, apparent solar time cannot be a
uniform time scale. The length of the solar day is also affected by the
inclination of the earth's spin axis to the plane of the earth's orbit. To
correct for the non-unif... | |
astropy_Time/deltaut1.html2_40_0.txt | ` aeroReadIERSData ` | ` dcmeci2ecef ` | ` lla2eci ` | ` eci2lla ` | ` eci2aer ` | ` mjuliandate `
### Topics | |
astropy_Time/time.html7_60_0.txt | This 3×3 matrix and its inverse perform the complete rotation between a vector in the ICRF and a vector in the dynamical reference system for this time and date.
` C ` , ` CT `
This 3×3 matrix and its inverse perform the complete rotation between a vector in the ICRF and a vector in the celestial intermed... | |
astropy_Time/time.html7_50_0.txt |
# Download and use the `finals.all` file.
ts = load.timescale(builtin=False)
[#################################] 100% finals2000A.all
As usual with data files, Skyfield will only download the file the first time
you need it, then will keep using that same copy of the file... | |
astropy_Time/item_list.htm4_8_0.txt | In 1967, the Thirteenth General Conference of Weights and Measures adopted a
resolution to replace the astronomical definition of the second - the second
is the duration of 9,192,631,770 cycles of radiation corresponding to the
transition between two hyperfine levels of the ground state of Caesium-133
atom. The Interna... | |
astropy_Time/time.html7_21_0.txt | The International Earth Rotation Service currently restricts itself to
appending a leap second to the last minute of June or the last minute of
December. When a leap second is inserted, its minute counts 61 seconds
numbered 00–60 instead of staying within the usual range 00–59. One recent
leap second was in June 2012... | |
astropy_Time/astropy_Time_37_0.txt | sort ( _ axis = -1 _ ) #
Return a copy sorted along the specified axis.
This is similar to [ ` sort() `
](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.sort.html#numpy.ndarray.sort
"\(in NumPy v1.26\)") , but internally uses indexing with [ ` lexsort() `
](https://numpy.org/doc/stable/r... | |
astropy_Time/deltaut1.html2_0_0.txt | Skip to content
Toggle Main Navigation | |
astropy_Time/item_list.htm4_3_0.txt | Apparent Solar Time
Apparent solar time is the time derived from the sun's apparent position. A
sundial indicates the apparent solar time directly. | |
astropy_Time/astropy_Time_10_0.txt | jd1 #
First of the two doubles that internally store time value(s) in JD.
| |
astropy_Time/internet-time-service-its3_24_0.txt | Most operating systems, such as Windows, MacOS, and Linux have an option to
automatically synchronize the system clock periodically by sending queries to
an NTP (network time protocol) server. This synchronization process normally
starts automatically when the system is bootstrapped and runs in the
background. The proc... | |
astropy_Time/time.html7_42_0.txt |
# When was Julian date zero?
bc_4714 = -4713
t = ts.tt(bc_4714, 11, 24, 12)
print(t.tt)
0.0
Did you notice how negative years work — that we expressed 4714 BC using the
negative number ` -4713 ` ? People still counted by starting at one, not
zero, when the schola... | |
astropy_Time/internet-time-service-its3_39_0.txt | JJJJJ YR-MO-DA HH:MM:SS TT L H msADV UTC(NIST) OTM
where: | |
astropy_Time/internet-time-service-its3_26_0.txt | * * *
NIST is now offering a network time service to deliver UT1 time. For details
about the UT1 server, please see the UT1 NTP Information page . | |
astropy_Time/internet-time-service-its3_10_0.txt | * Software
* Data
* Chemistry WebBook
* National Vulnerability Database
* Physical Reference Data
* Standard Reference Data (SRD)
* Storefront
* License & Patents
* Computer Security Resource Center (CSRC)
* NIST Research Library | |
astropy_Time/astropy_Time_15_0.txt | out_subfmt #
Unix wildcard pattern to select subformats for outputting times.
| |
astropy_Time/deltaut1.html2_8_0.txt | * Aerospace
* Aerospace Toolbox
* Environmental Models
* Environment | |
astropy_Time/item_list.htm4_12_0.txt | Is the Year 2000 a leap year?
According to the leap year rules of the Gregorian calendar, 2000 is divisible
by both 4 and 400 and thus the Year 2000 is a leap year. However, the century
years 1700, 1800 and 1900 are not leap years as the figures are not divisible
by 400. | |
astropy_Time/internet-time-service-its3_6_0.txt | * Environment
* Fire
* Forensic science
* Health
* Information technology
* Infrastructure
* Manufacturing
* Materials
* Mathematics and statistics
* Metrology
* Nanotechnology
* Neutron research
* Performance excellence
* Physics
* Public safet... | |
astropy_Time/deltaut1.html2_7_0.txt | Off-Canvas Navigation Menu Toggle
* Documentation Home | |
astropy_Time/internet-time-service-its3_30_0.txt | 2) Some systems implement the leap second by a frequency adjustment that
smears the leap second out over some longer interval either before or after
the event. This has the advantage that the clock never stops or appears to run
backward. However, it has both a time error and a frequency error with respect
to legal UTC ... | |
astropy_Time/internet-time-service-its3_37_0.txt | Many of the available NTP software clients for personal computers and network
elements (such as gateway or routers) don't do any averaging at all. Instead,
they make a single timing request to a signal server (just like a Daytime or
Time client) and then use this information to set their computer's clock. The
proper na... | |
astropy_Time/deltaut1.html2_20_0.txt | ## Examples
collapse all | |
astropy_Time/internet-time-service-its3_40_0.txt | * JJJJJ is the Modified Julian Date (MJD). The MJD has a starting point of midnight on November 17, 1858. You can obtain the MJD by subtracting exactly 2 400 000.5 days from the Julian Date, which is an integer day number obtained by counting days from the starting point of noon on 1 January 4713 B.C. (Julian Day zer... | |
astropy_Time/item_list.htm4_13_0.txt | Leap second
Coordinated Universal Time (UTC), the basis for our civil time, is
occasionally adjusted by one second called leap second to insure that the
difference between a uniform time scale defined by atomic clocks does not
differ from the Earth's rotational time by more than 0.9 seconds. | |
astropy_Time/time.html7_13_0.txt | If you want to use the current time, Skyfield leverages the minimal support
for UTC in the Python Standard Library to offer a ` now() ` function that
reads your system clock and returns the current time as a ` Time ` object
(assuming that your operating system clock is correct and configured with the
correct time z... | |
astropy_Time/time.html7_16_0.txt |
pip install pytz
Once it is installed, building a ` Time ` from a local time is simple.
Instantiate a normal Python ` datetime ` , pass it to the ` localize() `
method of your time zone, and pass the result to Skyfield: | |
astropy_Time/internet-time-service-its3_7_0.txt | * Publications
* Labs & Major Programs
* Laboratories
* Communications Technology Laboratory
* Engineering Laboratory
* Information Technology Laboratory
* Material Measurement Laboratory
* Physical Measurement Laboratory | |
astropy_Time/internet-time-service-its3_3_0.txt | https://www.nist.gov/pml/time-and-frequency-division/time-
distribution/internet-time-service-its
Search NIST | |
astropy_Time/astropy_Time_8_0.txt | info #
Container for meta information like name, description, format. This is
required when the object is used as a mixin column within a table, but can be
used as a general way to store meta information.
| |
astropy_Time/astropy_Time_16_0.txt | precision #
Decimal precision when outputting seconds as floating point (int value between
0 and 9 inclusive).
| |
astropy_Time/internet-time-service-its3_36_0.txt | ### Network Time Protocol (RFC-1305 and later versions)
The Network Time Protocol (NTP) is the most commonly used Internet time
protocol, and the one that provides the best performance. Large computers and
workstations often include NTP software with their operating systems. The
client software runs continuously as a... | |
astropy_Time/astropy_Time_28_0.txt | filled ( _ fill_value _ ) #
Get a copy of the underlying data, with masked values filled in.
Parameters :
**fill_value** [ ` object `
](https://docs.python.org/3/library/functions.html#object "\(in Python
v3.12\)")
Value to replace masked values with. Note that if this value is masked
See a... | |
astropy_Time/astropy_Time_13_0.txt | masked #
| |
astropy_Time/deltaut1.html2_31_0.txt | Out-of-range action, specified as a string.
Action to take in case of out-of-range or predicted value dates, specified as
a string: | |
astropy_Time/item_list.htm4_2_0.txt | Time Scale of Measurement
A time scale is a system of assigning dates to events. There are two widely
used time standards. One is based on astronomy and the other is the frequency
of atomic oscillations. | |
astropy_Time/time.html7_35_0.txt | If you instead slice along the second axis, then you can retrieve an
individual position for a particular date — and the first position is exactly
what was returned above when we computed the January 1st position by itself:
print(pos[:,0])
[-0.17461758 0.88567056 0.38384886]
| |
astropy_Time/internet-time-service-its3_20_0.txt | * * *
We are phasing out the ftp access to the time servers. All of the public files
on the time servers, including example source code for programmers who want to
write their own applications and ready-to-run applications for some common
operating systems, have been moved to this public ftp site:
ftp.boulder.nist.gov... | |
astropy_Time/astropy_Time_30_0.txt | insert ( _ obj _ , _ values _ , _ axis = 0 _ ) #
Insert values before the given indices in the column and return a new ` Time
` or [ ` TimeDelta ` ](astropy.time.TimeDelta.html#astropy.time.TimeDelta
"astropy.time.TimeDelta") object.
The values to be inserted must conform to the rules for in-place set... | |
astropy_Time/time.html7_27_0.txt | ## Date arithmetic ¶
Dates support a few simple math operations: | |
astropy_Time/internet-time-service-its3_47_0.txt | Twitter Facebook LinkedIn Instagram YouTube Giphy RSS Feed Mailing List
How are we doing? Feedback | |
astropy_Time/deltaut1.html2_43_0.txt | Run the command by entering it in the MATLAB Command Window. Web browsers do
not support MATLAB commands.
Close | |
astropy_Time/time.html7_44_0.txt | What are these three different uniform time scales?
International Atomic Time (TAI) is maintained by the worldwide network of
atomic clocks referenced by researchers with a need for very accurate time.
The official leap second table is actually a table of offsets between TAI and
UTC. At the end of June 2012, for examp... | |
astropy_Time/internet-time-service-its3_11_0.txt | * News & Events
* News
* Events
* Blogs
* Feature Stories
* Awards | |
astropy_Time/internet-time-service-its3_13_0.txt | * About Us
* Leadership
* Organization Structure
* Budget & Planning
* Contact Us
* Visit
* Careers
* Student programs
* Work with NIST
* History
* NIST Digital Archives
* NIST Museum
* NIST and the Nobel
* Educational Resources | |
astropy_Time/time.html7_26_0.txt |
# Asking for the leap_second flag to learn the whole story
dt, leap_second = t.astimezone_and_leap_second(eastern)
for dt_i, leap_second_i in zip(dt, leap_second):
print('{0} leap_second = {1}'.format(dt_i, leap_second_i))
2012-06-30 19:59:58-04:00 leap_secon... | |
astropy_Time/item_list.htm4_15_0.txt | Julian Date (JD) and Modified Julian Date (MJD)
Julian Date (JD) and Modified Julian Date (MJD) | |
astropy_Time/deltaut1.html2_27_0.txt | Array of UTC dates, specified as an M -by-1 array, represented as modified
Julian dates. Use the ` mjuliandate ` function to convert the UTC date to a
modified Julian date.
### Name-Value Arguments | |
astropy_Time/astropy_Time_1_0.txt | # Time #
_ class _ astropy.time. Time ( _ val _ , _ val2 = None _ , _ format =
None _ , _ scale = None _ , _ precision = None _ , _ in_subfmt = None
_ , _ out_subfmt = None _ , _ location = None _ , _ copy = False _ )
[ [source] ](../_modules/astropy/time/core.html#Time) #
Bases: [... | |
astropy_Time/astropy_Time_6_0.txt | format #
Get or set time format.
The format defines the way times are represented when accessed via the `
.value ` attribute. By default it is the same as the format used for
initializing the ` Time ` instance, but it can be set to any other value
that could be used for initialization. These can be listed w... | |
astropy_Time/internet-time-service-its3_35_0.txt | In addition to these services, we provide authenticated NTP messages using a
symmetric-key algorithm that is compatible with the reference implementation
of the NTP software. (For example, see www.ntp.org ) The authentication
ensures that the message originated from a NIST time server and was not
modified during tran... | |
python_descriptors_attribute/lookups_41_0.txt | Simply. | |
python_descriptors_attribute/howtousepythondictio_32_0.txt | A Python dictionary key can be nearly any Python object. I say "nearly"
because the object in question must be _hashable_ , meaning that it must have
a _hash value_ (the output of its ` __hash__() ` method) that does not change
over its lifetime, and which can be compared to other objects. | |
python_descriptors_attribute/howtousepythondictio_24_0.txt | Python dictionaries consists of one or more _keys_ —an object like a string or
an integer. Each key is associated with a _value_ , which can be any Python
object. You use a key to obtain its related values, and the lookup time for
each key/value pair is highly constant. In other languages, this type of data
structure i... | |
python_descriptors_attribute/Peter_Lamut_blog_24_0.txt | Skip to content
[ ](https://blog.peterlamut.com/)
[ Peter Lamut's blog ](https://blog.peterlamut.com/)
Mostly writings about Python and programming in general
Menu
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* [ Twitter ](https://twitter.com/plamut "Twitter: @plamut")
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python_descriptors_attribute/Peter_Lamut_blog_19_1.txt | l indices contained in
it: 1
>>> b = Bank() ... | |
python_descriptors_attribute/Peter_Lamut_blog_31_2.txt | ython internals ](https://blog.peterlamut.com/tag/cpython-internals/)
* [ Debugging ](https://blog.peterlamut.com/tag/debugging/)
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* [ Dictionary ](https://blog.peterlamut.com/tag/diction... | |
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python_descriptors_attribute/howtousepythondictio_18_0.txt | Senior Writer, InfoWorld | | |
python_descriptors_attribute/lookups_28_0.txt | **Author:** [ Axel Voitier ](mailto:axel.voitier@gmail.com) | |
python_descriptors_attribute/Peter_Lamut_blog_28_0.txt | Skip to content
[ ](https://blog.peterlamut.com/)
[ Peter Lamut's blog ](https://blog.peterlamut.com/)
Mostly writings about Python and programming in general
Menu
* [ Home ](/)
* [ Twitter ](https://twitter.com/plamut "Twitter: @plamut")
* [ GitHub ](https://github.com/plamut "GitHub: plamut")
* [ Stac... | |
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python_descriptors_attribute/lookups_87_0.txt | * __ **Stars:**
* __ **Forks:**
* __ **Open issues:**
* __ **Open PRs:** | |
python_descriptors_attribute/howtousepythondictio_15_0.txt | ### Learn how Python's dictionary data structure works as a powerful and
versatile way to store and retrieve objects and data in your applications. | |
python_descriptors_attribute/lookups_84_0.txt | ###### Project links | |
python_descriptors_attribute/lookups_48_0.txt | from lookups import InstanceContent, GenericLookup | |
python_descriptors_attribute/Peter_Lamut_blog_18_2.txt | m/start/)
* [ Log in ](https://wordpress.com/log-in?redirect_to=https%3A%2F%2Fr-login.wordpress.com%2Fremote-login.php%3Faction%3Dlink%26back%3Dhttps%253A%252F%252Fblog.peterlamut.com%252F2019%252F06%252F24%252Fdropping-into-a-debugger-with-the-built-in-debugger-function%252F)
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python_descriptors_attribute/lookups_123_0.txt | ### [ Hashes ](https://pip.pypa.io/en/stable/topics/secure-installs/#hash-
checking-mode "External link") for lookups-0.3.0-py3-none-any.whl | |
python_descriptors_attribute/lookups_47_0.txt | * ` lookups.InstanceContent ` provide write-access to the lookup: add/set/remove instances.
* ` lookups.GenericLookup ` provide read-access to search in the lookup. | |
python_descriptors_attribute/real_python_0_9.txt | of
different classes.
If you have any questions, leave a comment down below or contact me on [
Twitter ](https://www.twitter.com/mastro35) ! If you want to dive deeper into
Python descriptors, then check out [ the official Python Descriptor HowTo
Guide ](https://docs.python.org/3/howto/descriptor.html) .
Mark as Comp... |
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