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Stargazingon MarsStargazingon Mars

Cover PageEnvironmentConstellationsPolar AxisObserving MoonsObserving MarsMoon to MoonSolar EclipsesEarth from MarsImaging on MarsBack to Earth

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Your imaginary observatory location, 360 degrees unobstructed view, True dark sky.

Stargazingon

MARS

Stargazingon

MARS



Environment on MarsEnvironment on Mars

• Thin atmosphere, no industrial smog, no light pollution,• Excellent seeing and transparency (in absence of sand storms, etc.).

• Average temperature on Mars is -63ºC/-81.4ºF• Atmosphere is composed of 95.32% carbon dioxid and 7.2% nitrogen• Average atmospheric pressure is 0.007 bars (about 1/100th of Earth)• Gravity is 0.379 of Earth's.• A year on Mars is 1.881x of Earth, a day is about 40 minutes longer.



Different Constellations?Different Constellations?

It’s only a small step to Mars, but no giant leap into space.Therefore, the constellations appear like as seen from Earth.

Mars Rover Spirit’s image of Orion as viewed from 15 deg southern latitude on Mars.

Parallax angles to Proxima Centauri:on 1 AU base (Earth orbit): 0.773”on 1.524AU base (Mars orbit): 1.178”

Reason being:



Mars’s Polar AxisMars’s Polar Axis

• The orientation of Mars’s axis is different from Earth,• Mars has no obvious Pole Stars,• Inclination to ecliptic is 1.85º – same zodiac constellations, but different equinoxes and solstices,• Mars, too, is subjected to precession and axial tilt variation.

North

RA: 21h10m43s, Dec: 52º53’09

South

RA: 09h10m43s, Dec: -52º53’09



Observing the Martian MoonsObserving the Martian MoonsMoon Orbits to-scale



Observing the Martian MoonsObserving the Martian Moons

Influence of latitude

Influence of altitude

Apparent Angular Sizes



Dimensions

Surface distance

Center distance

Apparent size*

Visual magnitude

Orbit periodAxial rotation of Mars: 1.026 days

Observing the Martian MoonsObserving the Martian Moons

Fact Sheet

27 x 22 x 18 km

5,980 km

9,378 km

12.58’

-9mv max.

0.32 daysrises in the west

15 x 12 x 11 km

20,060 km

23,459 km

2.43’

-5.5mv max.

1.26 days

Phobos (‘fear’) Deimos (‘panic’)

*In the meridian on 45º latitude,measured on longest axis.

Angular size variations:Phobos: 45%,Deimos: 1.8’ to 2.6’

Image: Phobos-2, Feb 28, 1989 Image: Viking 2, h=30km, 1.2km wide

Image: Viking 2 Orbiter Image: Viking Orbiter



Observing Mars from its MoonsObserving Mars from its Moons

From Phobos

Simulated view on Valles MarinerisFOV: 120ºMars’ angular size: 42.5º (85x the full Earth moon)

From Deimos

Simulated view on the Hellas regionFOV: 120ºMars’ angular size: 16.7º (33x the full Earth moon)



Influence of relative orbit position

From Moon to MoonFrom Moon to Moon

• An exciting performance of fast changes,• Observing Phobos from Deimos is most dynamic• Phobos - Deimos minimum distance is 14,081km,• Phobos - Deimos maximum distance is 32,837km.

Min Distance

Max Distance

Phobos

6.59’ 2.83’

Deimos 3.66 1.57

Apparent Sizes

Phobos: 8.2º E/W elongationDeimos: 20º E/W elongation

Visibility Condition



Solar Eclipses on MarsSolar Eclipses on Mars

Phobos eclipse shadowMars Global Surveyor. August 26, 1999 overWestern Xanthe Terra. 250km (155mi across)

Phobos EclipseMars Rover OpportunityOn March 10, 2004

• Sun size is 2/3rd• Phobos’s is half of Earth Moon

Deimos EclipseMars Rover OpportunityOn sol 39 of its mission

• Sun size is 2/3rd• Deimos size is half of Phobos

• Eclipses occur several times a day • No total eclipses on Mars• Less spectacular than on Earth



Observing Earth from MarsObserving Earth from Mars

• Earth is an inner planet,• Shows phases like Venus/Mercury,• Mean greatest elongation is 41º,• Earth transits observable but rare. (last: May 11, 1984; next: Nov 10, 2084)

Mars Global Surveyor. May 8, 2003 13:00 UTC

Earth of the Past• Earth-Mars light time varies between 3 and 22 minutes. • In 22 minutes Earth rotates 5.5º towards East (1º in 4 minutes).

Venus transit in 2004. Courtesy K. Spencer.



Imaging on MarsImaging on Mars

Mars Rover Spirit Spirit’s two panoramic CCD cameras.

Our Mars Observatory

• Location: Gusev Crater, 15º south of equator• Mounting: altazimuth, no tracking• Pixel area: 1,024 x 1,024 pixels• Field of view: 16.8º• Resolution: 59” per pixel• Equivalent: 35mm SLR with 125mm lens• Cost: 400 million US$, excluding shipment

Spirit’s field of view




Orion




Phobos and Deimos




Phobos Lunar Eclipse




South Celestial Pole Region



Back to Earth – Thank You!Back to Earth – Thank You!

stargazing on mars stargazing on mars cover page environment constellations polar axis observing...

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