The Mars Apparition of 2006-2008

by Martin J. Powell

Following superior conjunction on October 23rd 2006 (when it passed directly behind the Sun) Mars emerged in the dawn sky in December 2006 as a relatively dim 'morning star', rising shortly before the Sun. Through the first half of 2007, the planet was best viewed from the Southern hemisphere. For Northern hemisphere observers, viewing circumstances were poor from late 2006 and throughout the first half of 2007, with Mars appearing low down in the Eastern sky at dawn. Mars became a prominently visible object from the Northern hemisphere around July 2007, by which time it was rising some three hours or so before the Sun. Viewing circumstances improved for both hemispheres as 2007 progressed.

From late 2006 through to November 2007, Mars moved steadily eastwards (i.e. direct motion) through the following constellations, slowly brightening as its distance from Earth reduced:

Mars began to brighten significantly from late August/early September of 2007 and reached opposition (i.e. its brightest for this apparition) on the night of December 24th 2007. Note that, although opposition took place on this date, Mars' closest approach to the Earth (at 0.5893 Astronomical Units or 88.15 million kms) took place a little earlier - on December 19th - because of its eccentric orbit.

With an apparent magnitude of -1.6 and a maximum apparent disk diameter of 15.8 arcseconds, Mars was not as bright nor as large (when seen through a telescope) as it was at its previous opposition in November 2005, when the planet reached magnitude -2.3 and had an apparent diameter of 20.1 arcseconds. This reduction in apparent size and brightness will continue at the next two oppositions, culminating in Mars' aphelic opposition in Leo in 2012.

For much of the period displayed in the above map, Mars was brighter than all of the stars shown, with a handful of exceptions. Capella ( Aur or Alpha Aurigae, apparent magnitude +0.08) exceeded Mars in brightness prior to late September 2007 and did so again after late February 2008; Betelgeuse ( Ori or Alpha Orionis, mag. +0.5v) and Procyon ( CMi or Alpha Canis Minoris, mag. +0.38) exceeded Mars in brightness after early March 2008 and Aldebaran ( Tau or Alpha Tauri, mag. +0.85) was brighter than the planet from early April 2008.

On opposition day (which co-incided with Christmas Eve in the Christian calendar), Mars was joined by the Full Moon, which passed close by the planet during the early morning hours (see Moon near Mars dates below). For Northern hemisphere observers, the planet was then due South at local midnight (due North at local midnight in the Southern hemisphere).

For Northern hemisphere observers, the 2007 Mars opposition saw the planet appear about as high as it can get in the sky at meridian transit (due South) providing optimal viewing conditions for telescopic observers, though this was rather offset by its less-than-favourable apparent size.

Telescopic observing conditions in the Southern hemisphere were less favourable, since there the planet appeared at its lowest possible angular elevation when at meridian transit (due North).

Mars faded rapidly after opposition as its distance from Earth increased, but it remained visible for some 11 months in the evening sky, slowly closing in on the setting Sun. From May 22nd-23rd 2008, the planet crossed the star cluster known as Praesepe (pronounced 'pree-SEE-pee') which is visible to the naked eye as a hazy patch of light (it is also known as Messier 44 , 'The Manger' or 'The Beehive Cluster' because of its binocular resemblance to a cloud of swarming bees). The planet's furthest distance from Earth for this apparition (2.5033 AU or 374.49 million kms) was reached on October 31st 2008, when its apparent diameter was a mere 3.7 arcseconds across. By late November 2008, Mars became lost from view in the dusk twilight.

Mars passed behind the Sun - at superior conjunction - on December 5th 2008. The 2009-2010 apparition began soon afterwards, which saw Mars in the constellation of Cancer when it next reached opposition on January 29th 2010 (for details, see the Mars 2009-10 page).

 [Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]

 ^ Back to Top of Page

Finding Mars from Orion, August 2007 to April 2008

Orange-red Mars was an easy object to find in the night sky throughout the period covered by the above star map.

Northern hemisphere observers looked for the well-known (and easily identifiable) constellation of Orion. They looked above (i.e. to the North of) Orion for the zodiacal constellations of Taurus and Gemini, where the planet was located.

Southern hemisphere observers looked below Orion for Taurus and Gemini, where the planet was located. The annotated photograph here indicates which pointer stars could be used to find Mars for the period through to April 2008.

Note that in the Northern hemisphere, Orion (and all the other constellations) appear tilted to the left (measured relative to the vertical) when in the Eastern half of the sky (before transit), upright (North up, as in the photo) when it transits the meridian (i.e. crosses the due South point), and tilted to the right when in the Western half of the sky (after transit). The greatest tilt angle occurs at the point of rising and setting, the actual angle depending upon the observer's latitude; the closer the observer is situated to the Equator, the steeper the angle of rise and set will be. At the Equator itself, constellations rise and set vertically; they are tilted 90º to the left when rising and 90º to the right when setting.

In the Southern hemisphere, Orion appears inverted (South up); it is tilted to the right when in the Eastern half of the sky and tilted to the left when in the Western half of the sky.

Orion rises due East and sets due West in both hemispheres.

^ Back to Top of Page

Moon near Mars Dates, August 2007 to May 2008

The Moon is easy to find, and on one or two days in each month, it passes Mars in the sky. The following table lists on which dates the Moon passed near the planet between August 2007 and May 2008:

The Moon moves relatively quickly against the background stars in an Eastward direction, at about its own angular width (0º.5) each hour (about 12º.2 per day). Because it is relatively close to the Earth, an effect called parallax causes it to appear in a slightly different position (against the background stars) when seen from any two locations on the globe at any given instant; the further apart the locations, the greater the Moon's apparent displacement against the background stars. Therefore, for any given date and time listed in the table, the Moon will have appeared closer to Mars when seen from some locations than others. For this reason, the dates shown in the table should be used only for general guidance.

^ Back to Top of Page

Mars Rise, Transit and Set Times for 2008

The following table lists the rising, transiting and setting times of Mars for a variety of latitudes from January to May 2008 (tables for the period from August to December 2007 can be seen here).

To find the appropriate times for any given location, the procedure is as follows:

1. Select the latitude which lies closest to your own location - the latitudes listed are 60º North, 50º North, 40º North, 30º North, 20º North, 0º (Equator), 15º South, 25º South and 35º South (if your latitude lies between any two of these, the times can be estimated by interpolating between the times given under the latitudes to either side). If you are unsure of your latitude and longitude, visit the Heavens Above website, select your country and enter the name of your nearest town or city using the search facility. For these purposes, latitude and longitude need only be taken to the nearest whole degree.

2. Select the required date and note down the rise, transit and set times shown in the relevant latitude column (dates are listed at 7 or 8 day intervals; if the required date is not listed, the times can be estimated by interpolating between that of the previous date and that of the following date),

3. If Daylight Savings Time (DST) is operating in your country, ADD ONE HOUR to the times you have noted down,

4. If your observing location is situated on - or very close to - the central longitude of your Time Zone, the times you have noted down will be accurate to within about 4 minutes. If, on the other hand, your observing location does not lie along  - or close to - the central longitude of your Time Zone (say, more than 2º away from it), you will need to apply a correction to the times you have noted down to allow for your own longitudinal position within your Time Zone (for any given location, this time correction needs only to be calculated ONCE, after which the same time correction will be applied to all times derived from the table),

5. Find the directions in which the planet will rise, transit and set for your selected latitude using the Rise/transit/set direction table. This also gives the angular altitude (angle above the horizon) that you will need to look for the planet when it reaches its highest point in your sky.

Examples of how to determine the rise, transit and set times of Mars using this procedure are given under the table for 2007.

Rise/Transit/Set Times Table

The table is colour-coded to reflect the sky conditions at the displayed time in each latitude:

Provided the sky is sufficiently dark, it is recommended that the observer waits about 30 minutes after the planet's rising time to allow the planet to reach a high enough altitude to clear the haze, turbulence and light pollution which is prevalent near the horizon - the latter being a particular problem in city and town locations. Likewise when setting, the observer should attempt to find the planet at least 30 minutes before its actual setting time. Be aware that, due to local sky conditions and an effect called atmospheric extinction (which causes celestial bodies to appear dimmer when they are close to the horizon), a planet or constellation may not be visible at all unless it is at least a few degrees above the horizon.

If Mars is some months away from opposition when it is observed, its coloration may not be immediately obvious to the naked eye; in which case, a pair of binoculars will help to reveal its trademark orange coloration.

Rise/Transit/Set Directions Table

The directions in which Mars rises, transits and sets depends upon the constellation in which Mars appears at the time, and also on the observer's latitude. To find the rising/transiting/setting direction of Mars for your own location, refer to the following table and look up the directions for the nearest appropriate latitude:

^ Back to Top of Page

Credits

• The star chart was compiled using a variety of sources, including the commercial software MegaStar (by Willmann-Bell, Inc), the freely-downloadable SFA Star Charts by Dan Bruton and the SkyGazer Ephemeris utility by John Biondo. Star colours were based on those shown in "Patrick Moore's Colour Star Atlas" (Mitchell Beazley Publishers Ltd., London, 1973).
• The times and separations of the lunar conjunctions with Mars (Moon near Mars dates) and the lunar phases were obtained from the commercial software RedShift 5 by Maris Technologies Ltd. using the 'Conjunctions' option of the 'Sky Diary'. The range of worldwide dates were obtained by determining the local times of the Moon and Mars conjunction at locations situated in the far Eastern hemisphere (Fiji Islands, GMT+12 hours) and the far Western hemisphere (Hawaiian Islands, GMT-10 hours).
• The rising, transit and setting times of Mars were obtained from RedShift 5. Sky colorations were determined using the software's 'True Sky Color' feature.

• The zodiac signs are from the free graphics site .

Copyright  Martin J Powell  November 2006