Philip P. Ide

Author, programmer, science enthusiast, half-wit.
Life is sweet. Have you tasted it lately?

User Tools

Site Tools


Adjustment to Mars Clocks

Martian clock showing time at the prime meridian The Martian clocks (keeping Martian time) on the Mars Weatherplugin-autotooltip__default plugin-autotooltip_bigMars Weather Reports

This webpage will soon be converted to be the top level page for Mars Weather Reports. It will contain links to the sub-pages, the clocks, the current location of Mars graphic and other data not spcific to the weather readings. The sub-pages will display the weather data from Insight, Curiosity and Perseverance.
page also display the Ls (pron. ell sub ess) - a way of describing where the planet is in its orbit1), and the displacement of the sun in the sky at midday. I noticed the value for this was out by some distance, and after pondering the problem (and the code) for a while, the penny dropped.

Unfortunately, the code was still generating a value that was out by 1/100th of a degree, which isn't much but it bothered me. It turned out to be due to a rounding issue, so I fixed that. Ls is now displayed to five decimal places. This value matches that generated by Mar24, a program available from the Goddard Institute for Space Studies, a branch of NASA.

For Earth, Ls advances approximately one degree per day (~0.9863°), but for Mars with its more eccentric orbit, things don't work out quite so neatly. Some Martian months are as short as 46 sols, while others are as long as 67 sols, so months are not determined by dividing the sols per year by 12. A new month begins when the planet reaches an increment of 30° around its orbit. Since Ls determines where in the orbit it is, it is the only viable way of determining what the current month is.

I also corrected the text on the same page, where it stated the Martian day was 39m 53s longer than a standard day on Earth, when it should have said 39m 35.2s. I don't know what I was thinking LOL

Technically, the Ls describes the position of the planet around the sun from the planet's perspective. Ls is 0° at the vernal equinox (beginning of northern spring), 90° at summer solstice, 180° at autumnal equinox, and 270° at winter solstice
This website uses cookies. By using the website, you agree with storing cookies on your computer. Also you acknowledge that you have read and understand our Privacy Policy. If you do not agree leave the website.More information about cookies
blog/articles/info/lsubs.txt · Last modified: 2020/06/07 12:06 by Phil Ide

Except where otherwise noted, content on this wiki is licensed under the following license: Copyright © Phil Ide
Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki
  • ISSplugin-autotooltip__default plugin-autotooltip_bigInternational Space Station

    This page has a portal through which you can view the current location of the International Space Station, updating in real-time. The tracker itself comes from the European Space Agency (ESA).

    There is also a handy link to get email notifications direct from NASA when the ISS is visible in your night sky.
  • Mars Weatherplugin-autotooltip__default plugin-autotooltip_bigMars Weather

    Weather Reports Insight Lander Perseverance Rover Curiosity data to come [Current positions of Earth and Mars] Image courtesy of and © Dominic Ford

    This image is updated once per week. A daily update is available on the Mars Solar Conjunctions page when such events are active.

    You can check the position of Mars vs the Sun and Earth for any date here:
  • Downloadsplugin-autotooltip__default plugin-autotooltip_bigDownloads

    Orbital Calculator Current Version This is a portable application, meaning there is no installer. Just unzip into a folder and run the executable. Since it is portable, it can be run from a USB stick.

    A full description and a list of the features are available
  • Orbital Calculatorplugin-autotooltip__default plugin-autotooltip_bigOrbital Calculator

    I needed to calculate orbital characteristics for any orbit around any gravitational mass (because I write sci-fi stories), so I wrote this program because I'm a programmer and I'm too lazy to do it by hand all the time. The program has expanded over the last few years, sometimes from suggestions by other writers. I make it freely available and as simple to use as possible. It now has a list of functions as long as your arm (assuming you're not a tentacle user), and the numbe…
  • Cookie Policy & GDPRplugin-autotooltip__default plugin-autotooltip_bigCookie Policy & GDPR

    There are NO tracking cookies on this site!

    The Cookie policy is straightforward. This site only uses cookies that are required to make your experience of using this site better, and only uses session cookies (see exceptions below). Session cookies are deleted when you close your browser.
  • Book Reviewsplugin-autotooltip__default plugin-autotooltip_bigBook Reviews

    Here you can find all the book reviews, broken down by genre, and further subdivided by author. If you want me to review your novel, please read my Rules on Reviewing.

    * Science-Fiction * Fantasy * Non-Fiction
  • Contactplugin-autotooltip__default plugin-autotooltip_bigContact

    If you have a burning desire to contact me, use the discussion form below. Anything you say remains private between you and me.