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August 10 2021 Aladin, page layout, setxkbmap, Apache Bench, Met Office Datapoint

Posted on August 13, 2021
( 6 minute read )

David shared the rather underwhelming photo of BepiColumbo skimming past Venus.

Bernard shared some more of his work for the Astronomy centre, focusing on the Aladin client. One of the problems in astronomy is determining a zero point from which coordinates can be calculated. Traditionally the zero point had been determined as the equinox but it is now determined by using a catalogue of distant objects which are apparently stationary but whose positions can be determined. This has led to a formal definition of the International Celestial Reference System (ICRS) which the Python package astropy will convert by using a website which gives the earth’s position at present.

For the purposes of the Astronomy Centre project most current packages of astronomical data are over-complex. However, he had found an obsolete package which was reasonably accurate and used HEALPix diamond numbers.

HEALPix is a way of dividing the sky up into diamond shaped equal area cells; the catalogue of sightings by the Gaia observatory which is circulating the sun has HEALPix diamond numbers.

He then demonstrated using the Hierarchical Progressive Survey (HiPS) software to zoom in on a particular area of the sky.

Bernard has managed to store the HEALPix diamond numbers in an SQLite table. Multi-Order Coverage (MOC) maps allow you to compare different areas of the sky by comparing the HEALPix diamond numbers for the areas surveyed.

Brian who had been logged in but invisible and muted became audible briefly and explained that, on returning to the UK, he had found that nothing worked!

John gave a presentation based on the HTML and page layout paper in which he drew attention to the two different publishing traditions: continuous flow and page based. Early software like WordStar and TeX had been based on the continuous flow paradigm but desktop publishing software had adopted the page based approach as had HTML in the early part of the 20th century. However, since 2011 HTML and CSS had gone back to the continuous flow paradigm though most popular website software was still page based.

John asked whether Darren had been able to solve his keyboard language problem saying that he had discovered that KDE->System settings simply uses setxkbmap.

David pointed out that it should be possible to configure a permanent layout.

He went on to describe an apparent DDoS attack on a server when someone was using Apache Bench to generate multiple requests for publicly available data. An examination of the Apache logs identified the problem and they simply added a line to the config file to detect Apache Bench and return 500; those using this method seem to have given up. Some of the requests came from a VPS in the Netherlands and many from NordVPN nodes around the world.

Other ways of dealing with the situation might have been to add a CAPTCHA or a request to sign on; perhaps they could give out an API key to legitimate users.

Bernard mentioned that to access the Met Office Datapoint, for which your need a key, you can now use longitude and latitude whereas previously you had to use the nearest weather station. David said that he was currently using the Norwegian Met Office for Home Assistant; perhaps he should try the UK Met Office. Bernard shared the definitions of Met Office weather codes.

David has been sustaining IT Stuff during the pandemic on his own, sometimes playing extra music to fill up the time. Recent items have been the move by China to IPv6 by 2025 which will make it easier to block IPv4, the eBay manager who has gone to jail for stalking, the AI program which was very successful in picking up where Covid-19 was rampant except that it was basing this on an analysis of the fonts being used on the hospital computers and the ransomware attack on the Flowbird ticket machines installed in Northern Trains stations.

In response to a question about returning to BCB, David said that BCB are having a planning meeting the week after next; nothing so far has happened in relation to the proposed move.

David also mentioned the news that had emerged today that the NASA spacesuits would not be ready for the planned trip to the moon in 2024 and a question about how many different shades of blue you could find on the Internet being used for logos and so on.