Image Credit & Copyright: NASA/JPL/USGS of Mars’s Schiaparelli Crater (front & center) by the Viking 1 Orbiter.
Some of you I know have already been enjoying the view every morning as the Mars, Saturn and Antares trio have been rising before the Sun in a close triangle formation recently and what a sight it is. If you haven’t seen this yet I would urge you to do so because it’s a fantastic view that promises to get even better through summer.
That aside, Mars is special right now for another reason; it’s nearing opposition which will take place on Sunday, May 22, 2016.
Opposition, in planetary terms is when a superior (outer) planet reaches a point almost exactly opposite the Sun from Earth’s vantage point so we see its full disk so you can call it a “Full Mars.” Another way to say it is Earth will be directly between the Sun and Mars. That, for as technical as we need to be, places Mars at its closest point that it can get to the Earth in its orbit (perigee). Opposition and actual perigee points differ slightly but close enough for what we’re doing.
That’s pretty exciting as Mars will be at its best and brightest for us but it’s important to remember that Mars is small and far away so for most of us, unless you have a decent aperture telescope, it will still appear as an orange ball and surface features will evade view.
To put it a different way let’s take a look at how most of us amateur astronomers judge these things; by their apparent properties. Basically “apparent” is short for how things look on the sky, to us here on the ground. For example, the Sun and Moon both have the same apparent dimensions (also known as angular diameter) at a half-degree on the sky when in reality the Sun is 400 times the diameter of the Moon. At opposition, Mars’s apparent diameter on the night sky will reach about 18.5” arcseconds. For perspective, Jupiter right now is an apparent size of 41.7” arcseconds so you can easily see that even though Mars will be at its best, it’s still a very small target to see detail.
Below I’ve listed a bunch of my favorite links to use and abuse because they’re invaluable assets for sky watching and as always, if you have questions, please ask!
Dominic Ford’s “In-The-Sky” page for this event: https://in-the-sky.org/news.php?id=20160522_13_100
In-The-Sky’s, Solar System Body Finder Chart: https://in-the-sky.org/findercharts.php
U.S. Naval Observatory (USNO) Solar System Body Dimensions: http://aa.usno.navy.mil/data/docs/diskmap.php
U.S. Naval Observatory (USNO) Rise & Set Times: http://aa.usno.navy.mil/data/docs/mrst.php
Courtney Seligman’s (cseligman) Mars Oppositions page: http://cseligman.com/text/planets/marsoppositions.htm
The Sky Live page for Mars: http://theskylive.com/mars-info
The Sky Live, Mars Tracker: http://theskylive.com/mars-tracker
Chris Peat’s “Heavens-Above” Planet Summary: http://heavens-above.com/PlanetSummary.aspx
The Planets Today (current solar system configuration): http://www.theplanetstoday.com/
Time and Date Sunrise and Sunset calculator: http://www.timeanddate.com/sun/
Time and Date Moonrise and Moonset calculator: http://www.timeanddate.com/moon/