Use builtin=True more consistently for timescales

It looks like http://maia.usno.navy.mil/ is down this morning, which
reminds me that documentation should be more consistent in loading
timescales from internal files unless illustrating explicitly how to
download up-to-date files.

README.rst

@@ -15,7 +15,7 @@ positions for planets and Earth satellites.
    planets = load('de421.bsp')
    earth, mars = planets['earth'], planets['mars']
 
-   ts = load.timescale()
+   ts = load.timescale(builtin=True)
    t = ts.now()
    position = earth.at(t).observe(mars)
    ra, dec, distance = position.radec()

skyfield/documentation/almanac.rst

@@ -14,7 +14,7 @@ an ephemeris file that provides positions from the planets:
 
     from skyfield import api
 
-    ts = api.load.timescale()
+    ts = api.load.timescale(builtin=True)
     eph = api.load('de421.bsp')
 
 Then, load the “almanac” module.

skyfield/documentation/api-position.rst

@@ -13,7 +13,7 @@ that can be used to express them.
    from __future__ import print_function
    from skyfield.api import load
    from skyfield.positionlib import ICRF
-   ts = load.timescale()
+   ts = load.timescale(builtin=True)
    de421 = load('de421.bsp')
    earth = de421['Earth']
    mars = de421['Mars']

skyfield/documentation/astropy.rst

@@ -30,7 +30,7 @@ between the two libraries:
       atime = Time('2010-01-01T00:00:00', scale='utc')
       print(atime)
 
-      ts = load.timescale()
+      ts = load.timescale(builtin=True)
       t = ts.from_astropy(atime)
       print(t.utc_jpl())
 
@@ -55,7 +55,7 @@ between the two libraries:
       planets = load('de421.bsp')
       earth = planets['earth']
 
-      ts = load.timescale()
+      ts = load.timescale(builtin=True)
       t = ts.utc(1980, 1, 1)
       barycentric = earth.at(t)
 

skyfield/documentation/earth-satellites.rst

@@ -140,7 +140,7 @@ Note that ``ts`` should be a timescale object:
 
     from skyfield.api import EarthSatellite
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     line1 = '1 25544U 98067A   14020.93268519  .00009878  00000-0  18200-3 0  5082'
     line2 = '2 25544  51.6498 109.4756 0003572  55.9686 274.8005 15.49815350868473'
     satellite = EarthSatellite(line1, line2, 'ISS (ZARYA)', ts)
@@ -691,8 +691,7 @@ that builds a satellite model directly from numeric orbital parameters:
     )
 
 If you need any more details,
-this ``sgp4init`` constructor
-is documented in the
+this ``sgp4init`` method is documented in the
 `Providing your own elements <https://pypi.org/project/sgp4/#providing-your-own-elements>`_
 section of the sgp4 library’s documentation on the Python Packaging Index.
 

skyfield/documentation/elements.rst

@@ -14,8 +14,8 @@ Generating Elements
 ===================
 
 Call :func:`~skyfield.elementslib.osculating_elements_of()` to generate
-an :class:`~skyfield.elementslib.OsculatingElements` object.  For 
-example, here is how to find the osculating elements of the moon 
+an :class:`~skyfield.elementslib.OsculatingElements` object.  For
+example, here is how to find the osculating elements of the moon
 orbiting earth:
 
  .. testcode::
@@ -23,7 +23,7 @@ orbiting earth:
     from skyfield.api import load
     from skyfield.elementslib import osculating_elements_of
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.utc(2018, 4, 22, range(0, 25))
 
     planets = load('de421.bsp')

skyfield/documentation/examples.rst

@@ -80,7 +80,7 @@ and 270° at the Last Quarter.
 
     from skyfield.api import load
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.utc(2019, 12, 9, 15, 36)
 
     eph = load('de421.bsp')
@@ -121,7 +121,7 @@ and 270° if the Sun is to the right of the Moon.
     from skyfield.api import load, Topos
     from skyfield.trigonometry import position_angle_of
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.utc(2019, 9, 30, 23)
 
     eph = load('de421.bsp')
@@ -177,7 +177,7 @@ like the Sun, Moon, or one of the planets.
     from skyfield.almanac import find_discrete, risings_and_settings
     from pytz import timezone
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t0 = ts.utc(2019, 1, 19)
     t1 = ts.utc(2019, 1, 21)
 
@@ -212,7 +212,7 @@ then Skyfield can return its right ascension and declination.
 
     from skyfield import api
 
-    ts = api.load.timescale()
+    ts = api.load.timescale(builtin=True)
     t = ts.utc(2019, 9, 13, 20)
     topos = api.Topos(latitude_degrees=42, longitude_degrees=-87)
     observer = topos.at(t)
@@ -296,7 +296,7 @@ to both Accra, Ghana, and the top of Mount Bierstadt in Colorado.
    from skyfield.api import Topos, load
    from skyfield.functions import length_of
 
-   ts = load.timescale()
+   ts = load.timescale(builtin=True)
    t = ts.utc(2019, 1, 1)
 
    bierstadt = Topos('39.5828 N', '105.6686 W', elevation_m=4287.012)

skyfield/documentation/index.rst

@@ -37,7 +37,7 @@ Computing the position of Mars in the sky is as easy as:
     planets = load('de421.bsp')
     earth, mars = planets['earth'], planets['mars']
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.now()
     astrometric = earth.at(t).observe(mars)
     ra, dec, distance = astrometric.radec()

skyfield/documentation/positions.rst

@@ -119,7 +119,7 @@ or else by generating a whole series of positions.
 
     from skyfield.api import Topos, load
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.now()
 
     planets = load('de421.bsp')
@@ -155,7 +155,7 @@ or else by generating a whole series of positions.
 
     from skyfield.api import Star, Topos, load
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.now()
 
     boston = earth + Topos('42.3583 N', '71.0603 W')
@@ -181,7 +181,7 @@ or else by generating a whole series of positions.
 
     from skyfield.api import EarthSatellite, Topos, load
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.now()
 
     line1 = '1 25544U 98067A   14020.93268519  .00009878  00000-0  18200-3 0  5082'

skyfield/documentation/searches.rst

@@ -51,7 +51,7 @@ and then the angle between those positions:
 
     from skyfield import api
 
-    ts = api.load.timescale()
+    ts = api.load.timescale(builtin=True)
     t = ts.utc(2020, 6, 2)
 
     eph = api.load('de421.bsp')

skyfield/documentation/stars.rst

@@ -64,7 +64,7 @@ the star:
     planets = load('de421.bsp')
     earth = planets['earth']
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.now()
     astrometric = earth.at(t).observe(barnards_star)
     ra, dec, distance = astrometric.radec()
@@ -187,7 +187,7 @@ pass tuples instead of floats:
     barnard = Star(ra_hours=(17, 57, 48.49803),
                    dec_degrees=(4, 41, 36.2072))
 
-    ts = load.timescale()
+    ts = load.timescale(builtin=True)
     t = ts.now()
     astrometric = earth.at(t).observe(barnard)
     ra, dec, distance = astrometric.radec()

skyfield/timelib.py

@@ -316,7 +316,7 @@ class Time(object):
     You will typically not instantiate this class yourself, but will
     rely on a Skyfield ``Timescale`` object to build dates for you:
 
-    >>> ts = load.timescale()
+    >>> ts = load.timescale(builtin=True)
     >>> print(ts.utc(1980, 1, 1))
     <Time tt=2444239.5005924073>
 
@@ -908,7 +908,7 @@ using its methods, which let you either specify a calendar date or else
 supply a raw Julian date value with the "jd" keyword:
 
         from skyfield.api import load
-        ts = load.timescale()
+        ts = load.timescale(builtin=True)
         t = ts.utc(1980, 4, 20)       # the new way
 
         t = ts.tt(jd=2444349.500592)  # jd is also supported for tai, tt, tdb