USNO files server look down

How to reproduce

>>> from skyfield import api
>>> ts = api.load.timescale()
Traceback (most recent call last):
  File "/usr/lib/python3.6/urllib/request.py", line 1318, in do_open
    encode_chunked=req.has_header('Transfer-encoding'))
  File "/usr/lib/python3.6/http/client.py", line 1239, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/lib/python3.6/http/client.py", line 1285, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.6/http/client.py", line 1234, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.6/http/client.py", line 1026, in _send_output
    self.send(msg)
  File "/usr/lib/python3.6/http/client.py", line 964, in send
    self.connect()
  File "/usr/lib/python3.6/http/client.py", line 936, in connect
    (self.host,self.port), self.timeout, self.source_address)
  File "/usr/lib/python3.6/socket.py", line 704, in create_connection
    for res in getaddrinfo(host, port, 0, SOCK_STREAM):
  File "/usr/lib/python3.6/socket.py", line 745, in getaddrinfo
    for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno -2] Name or service not known

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/novapost/.virtualenvs/EXP3/lib/python3.6/site-packages/skyfield/iokit.py", line 477, in download
    connection = urlopen(url)
  File "/usr/lib/python3.6/urllib/request.py", line 223, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib/python3.6/urllib/request.py", line 526, in open
    response = self._open(req, data)
  File "/usr/lib/python3.6/urllib/request.py", line 544, in _open
    '_open', req)
  File "/usr/lib/python3.6/urllib/request.py", line 504, in _call_chain
    result = func(*args)
  File "/usr/lib/python3.6/urllib/request.py", line 1346, in http_open
    return self.do_open(http.client.HTTPConnection, req)
  File "/usr/lib/python3.6/urllib/request.py", line 1320, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [Errno -2] Name or service not known>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/novapost/.virtualenvs/EXP3/lib/python3.6/site-packages/skyfield/iokit.py", line 275, in timescale
    data = self('deltat.data')
  File "/home/novapost/.virtualenvs/EXP3/lib/python3.6/site-packages/skyfield/iokit.py", line 185, in __call__
    download(url, path, self.verbose)
  File "/home/novapost/.virtualenvs/EXP3/lib/python3.6/site-packages/skyfield/iokit.py", line 479, in download
    raise IOError('cannot get {0} because {1}'.format(url, e))
OSError: cannot get http://maia.usno.navy.mil/ser7/deltat.data because <urlopen error [Errno -2] Name or service not known>

Notes

1. It looks like the whole service is down => https://downforeveryoneorjustme.com/maia.usno.navy.mil
2. there’s no flag available to avoid trying to download up-to-date files, so the program crashes
3. the latest deltat.data file that we can find on this repository looks obsolete

Are there any mirrors available or alternative data sources?

[brandon-rhodes]

I have just released https://pypi.org/project/skyfield/1.11/ — enjoy!

[brandon-rhodes]

@HelloWorldIL Thanks! I have turned your example code into a formal test and fixed the issue. Could you try again?