Mars Observing FAQ and Links: 2003 Opposition

This page describes the 2003 opposition of Mars, the closest opposition in 73,000 years (or maybe 59,604 years, depending how how you calculate it; both of those numbers come from different calculations by Jean Meeus). At its closest approach, Mars will be 34,646,418 miles (55,758,006 km) from the earth.

Closest approach is at 9:51am UT (2:51 am PDT) on Aug. 27, 2003.
Perihelion (Mars' closest approach to the sun) happens 32 hours later.

Near opposition, Mars will have an angular diameter of 25.1" (comparable to Jupiter), vs. 14" at aphelic oppositions. Brightness will also be comparable to Jupiter's brightest, at magnitude -2.9. Observers in Northern California will see Mars transit about 37 degrees above the southern horizon. (Observers farther south will get better views, with Mars higher in the sky.)

Throughout the opposition, Mars' southern hemisphere will be tilted toward us. The southern spring equinox (with the southern polar cap at its maximum size) happens on May 6, and southern summer solstice is September 29. We should be able to see good detail (with the disk 20" or larger) from mid-July through early October. Supposedly, the risk of major dust storms, like the one that ruined the detail for the opposition two years ago, is low in this season. Let's hope!

Astronomy magazine has a good timeline for the 2003 opposition.

If you have questions on observing Mars, or answers which you think belong in a FAQ, please mail.

Mars Observing FAQ

Q. What's an opposition, and why do I care?
A. Opposition is when an outer planet is opposite the sun as seen from earth; i.e., when it is closest to us. A planet appears bigger at opposition, and details are easier to see than at other times. In the case of Mars, the difference in size and visible detail is dramatic.

Note that the month or so after the opposition is also a good time to observe; although the planet will be starting to recede, it will be rising earlier in the evening than at opposition, which makes it easier for most people to observe it when it's high in the sky.

Q. What sort of equipment do I need to look at Mars?
A. Just about any telescope will do. I've seen some detail on Mars, during the 1997 opposition, with my 4.25" f/4 reflector, though that's certainly not an ideal planetary telescope. A good 6" f/8 reflector or 4" refractor should show a lot of Mars detail if the air is steady and if the telescope is in good collimation. I've also gotten excellent views of Mars through big dobsonian reflectors: although a clock drive is convenient for high magnification observations, don't let that stop you if you happen to have a dob. In 2003 I've done most of my observing so far with my homebuilt 8" dobsonian.

Binoculars won't show you any more than you see with the naked eye: just a bright red point.

Steady air and magnification are more important than telescope aperture, ultimately; you'll have the best luck when Mars is high in the sky, and it may help to find a location at high elevation or at least one where you're not looking over houses, cars or asphalt.

Q. Do I need filters to observe Mars?
A. No, but they can sometimes help in bringing out detail. They're especially helpful if you have an inexpensive refractor which has some chromatic aberration (meaning that it shows some colored fringes around bright objects): filters can dramatically cut down the color fringing. See specifics on the ALPO page.

Q. What can I see with a small telescope?
A. Hellas (a bright impact basin), some dark features like Syrtis Major, Mare Erythraeum, Mare Acidalium, and Niliacus Lacus, more subtle dark features like Margaritifer Sinus, Sinus Sabaeus, Lacus Solis (the "Eye of Mars"), and polar caps (in 2003, mostly the southern polar cap, which has a nice dark ring around it and ragged edges).

With filters, you can sometimes see clouds and hazes of various types. With exceptional seeing, there are many other light and dark features which become visible, and you can look for details on the edges of the features, and for clouds over the Tharsis volcanos. You may even see parts of Valles Marineris, near Lacus Solis.

Sorry, you won't see canals -- there aren't any. But there's plenty of other stuff to look at!

Q: Why can't I see anything at all?
A: Mars is small. Really small. The details are smaller still. You really have to practice and have patience. The details will come, but don't expect them to be easy. Try for the polar cap first: that's usually the easiest to see. Then try to see some dark markings on the planet. The more you observe the planet, the more you'll learn how to see the detail on it.

Q. How can I train my observing skills?
A. Observe a lot -- start well before the opposition if you can, even if Mars is small or low in the sky. That way, by opposition you'll be ready to see all the detail which is there.

Also, try sketching the detail that you see -- even if you don't consider yourself an artist (I'm certainly not), sketching planetary detail really helps you think about what you're seeing, as well as being fun in its own right.

Q. How do I figure out what part of the planet I'm looking at and how it's oriented at the time when I'm looking?
A. That's one of the tricky parts of observing Mars, especially during this opposition when the polar cap is expected to be inconspicuous.

One way is to use a Mars globe, if you can find one (see the Links section for some suggestions).

The other, and easier, method of orientation is to use a computer program. See the software links below for programs which show Mars rotated correctly for a particular time and date.

Q. Can I see Mars' moons?
A. The moons should, in theory, be visible in large amateur telescopes (say, a 10" or so), but they're quite difficult due to their closeness to the high surface brightness image of Mars. Phobos is brighter, but Deimos is farther from Mars. It helps to move Mars just out of the field, or to use an "occulting bar" in the eyepiece to block out the brightness of Mars. It's a challenge, but it's definitely possible!

... Mars Links ...

Labelled Mars Maps Online

• BAA Maps of Mars Several quite different maps.
• ALPO Mars Map (black & white) I've been using a modified version of this map myself: it's very easy to follow, but a few of the labels are wrong, and some of the white labels get lost when it's printed out, so I made a new version with drop shadows on the white labels and a few label corrections, included here by permission of the ALPO map copyright owners, Daniel M Troiani and the Association of Lunar & Planetary Observers - Mars Section.
• Ralph Aeschliman has a selection of lovely airbrushed Mars maps
• USGS Mars Maps & Globes This site has kits to download and build an excellent Mars globe from a PDF made from Mars Viking and Global Surveyor mosaics. Excellent! The Mars Viking Image Mosaic Globe (flower petal image, 3.3Mb PDF) is the best for observers.
• I made some color maps of my own by adding labels to the JPL Mars maps because I needed them for my java applet; you can get my original map here, and Bill Arnett contributed an east-west flipped and a north-south rotated version.
• The Yahoo list Marsobservers has some Mars Maps in its files section but I think you have to join the list to access them.
• USGS Mars Map Generator I'm getting "connection refused" for this, but I'm leaving the link here because it's still in google so I'm hoping it's a temporary glitch. It was a really useful site and I hope it still exists.
• Eric Jamison's Mars map

Unlabelled Mars Maps Online

• Make Your Own Mars Icosohedron Globe Very useful if you can't find a ready-made Mars globe; also has lots of other links and info about Mars
• MGS MOC Mars Map a high-res map of Maps using Global Surveyor images
• MarsNet CGI Mars Simulator enter the date and UTC time and it shows you Mars
• JPL's space simulator Views of any solar system object as it looks at a specified time. Unfortunately, it doesn't show much detail on Mars so I haven't found it very helpful for figuring out which features are pointed toward us at a given time. No feature labels.
• JPL Mars maps
• National Geographic map
• Atlas of Mars and Viking Orbiter image-finder
• NASA Mars Atlas
• Nicolas Biver's sketch map

Places to buy Mars Maps and Globes

• Replogle makes my favorite Mars globe; it's 4", shows albedo features and used to be sold in toy stores in an inexpensive set with a (marginally useful) moon and (fairly poor) earth globe. Unfortunately it has become very difficult to find; I've heard that it's possible to buy these from Replogle in quantity and someone may be reselling them on ebay, so try searching ebay for "mars globe".
• Inflatable Mars globes: I got one of these at RTMC. It doesn't have many features labelled, but you can correct that with a magic marker. Hint: stick a red flashlight up against one side of it and the whole balloon turns an eerie red-orange -- great for public events. I bought mine from the "Astronomy To Go" booth at RTMC; they don't have a web page, but they are astro2go@aol.com and (215)831-0485 and they say they still have inflatable globes in stock for $6.00.
• Hugg-A-Planet Mars Stuffed, and looks like the labelling is quite good -- too good, because they're currently out of stock, "updating cartography". Sigh.
• WARD's Natural Science" Mars soil kit comes with a globe that looks suspiciously like the little Replogle one, plus a good-looking map. Sure would be nice if you could get just the globe and/or map!
• The RASC Observer's Handbook has a decent B&W Mars map and lots of observing info (lots of great info on observing other objects, too).
• Sky Publishing Mars Globe is still available, but it's large and expensive. They also have a Mars Topography Globe (false color, not as well suited to observing) Their flat Mars Map is out of stock -- wouldn't you know it!

Observing Info on the 2003 Apparition

• AANC Mars 2003 Opposition An excellent and comprehensive collection of links
• Sky & Telescope's Mars page
• The Mars Observer's Tool Kit from Geoff Gaherty of the RASC
• ALPO Mars Section, including a yahoo mailing list and a page on THE GREAT 2003 PERIHELIC APPARITION OF MARS which offers information about filters, how to submit ALPO observing reports, and other details.

General Info

• Mars from The Nine Planets All the basic information, and lots of links
• Mars from Solarviews
• USGS: Mars Nomenclature
• The Planet Mars: A History of Observation and Discovery an online book by William Sheehan
• JPL Horizons Ephemeris Generator

Software packages which shows Mars' rotation and surface features

• Marsmap, my open source mars viewer for PalmOS.
• XEphem Unix/Linux open-source freeware (also runs on Mac OS X and maybe Windows).
• Starry Night Mac and Windows Planetarium program (not free) known for its pretty images, and the newer versions offer excellent Mars support (you may have to turn on the "Planetary Atmospheres" feature).
• Guide Windows planetarium program (not free) known for its accuracy.
• Meridian Windows freeware which apparently shows Mars features
• Mars Previewer Windows freeware. Warning! Some versions of Mars Previewer were apparently infected with a virus! See Astronomy Magazine for more details. You're on your own for finding a place to download a clean copy -- sorry.

Online software

• My new Java Marslet
• Sky & Telescope's Javascript Mars Profiler
• CalSKY Mars View (features unlabelled)
• Sky & Telescope's Javascript Mars Moons