TOTD 2018-03-30: The Moon, Up Close and Personal

Since 1994, Fourmilab’s Earth and Moon Viewer has provided custom views of the Earth and Moon from a variety of viewpoints, using imagery databases which have evolved over the years from primitive images to gigabyte-scale mosaics collected by spacecraft.  Views were originally restricted to the Earth, but fifteen years ago, in April 2003, the ability to view the Moon was added, using the global imagery collected by the Clementine orbiter.  These data were wonderful for the time, providing full-globe topography and albedo databases with a resolution of 1440×720 pixels.  This allowed viewing the Moon as a whole or modest zooms into localities, but when you zoomed in close the results were…disappointing.  Here is the crater Copernicus viewed from an altitude of 10 km using the Clementine data.

Moon, Copernicus crater, 10 km altitude, Clementine data... [Read More]


Ratburger: The Next Hundred

One of the principles of since its inception is Radical Transparency—everything about the site, from its source code, updates, and access statistics—shall be accessible to anybody who is interested.  There are a few statistics which, due to the design of WordPress, are not generally accessible, which may be of interest.  Excluding administrators and accounts they use for testing various features on the site, we now have 77 members, the vast majority of whom are active and regularly visit the site, comment, and post.  Since the site went live (in stealth mode) on 2017-12-10, there have been 506 posts and 5,589 comments on them.  The software that runs the site, publicly disclosed on GitHub for anybody interested in setting  up a competing site, or one appealing to a different audience, has had 86 publicly-posted builds since Git management began on 2017-12-18.

With today’s release of browser-pull dynamic updates of notifications, I consider the site “feature complete” as I envisioned it at the launch last December.  With all of the local modifications, as documented in the Updates Group (available for anybody to read), it provides a discussion forum, interest groups, podcasts (we don’t produce them, but provide links to those to which our members regularly listen), private messages, a weekly free conference call, and on-line chat.  And all of this is completely free and devoid of advertisements and other intrusive distractions.... [Read More]