Observing Mars with a Telescope - Revision history

Sdubois: /* What features can be observed? */

2019-09-18T19:05:11Z

What features can be observed?

Sdubois: /* What features can be observed? */

2019-09-18T19:01:17Z

What features can be observed?

Sdubois: /* What features can be observed? */

2019-09-18T19:00:41Z

What features can be observed?

Sdubois at 18:55, 18 September 2019

2019-09-18T18:55:53Z

Sdubois at 19:57, 15 September 2019

2019-09-15T19:57:22Z

Sdubois at 19:50, 15 September 2019

2019-09-15T19:50:37Z

Sdubois: /* Other factors affecting observation */

2019-09-15T19:50:02Z

Other factors affecting observation

Sdubois: /* Other factors affecting observation */

2019-09-15T19:44:59Z

Other factors affecting observation

Sdubois: /* Other factors affecting observation */

2019-09-15T19:41:24Z

Other factors affecting observation

Sdubois: /* What features can be observed? */

2019-09-15T19:33:01Z

What features can be observed?

@@ Line 38: / Line 38: @@
 [[File:MarsStormBeforeAfter.jpg|right|thumb|Global dust storms such as that of July 2018 can obscure even the most readily apparent features. South is up in this image.]]
-All three of these regions can be obscured by [[dust storms]] which can grow to cover the entire planet.<ref name=":0" /> These typically occur during the northern hemisphere’s summer, when the planet is closest to the Sun and additional heat increases wind activity. This, combined with Mars’ low [[gravity]] and [[Atmosphere|atmospheric pressure]] contribute to the ease with which dust is kicked up into planet-encompassing storms.<ref name=":0" />
+All three of these regions can be obscured by [[dust storms]] which can grow to cover the entire planet.<ref name=":0" /> These typically occur during the northern hemisphere’s summer, when the planet is closest to the Sun and additional heat increases wind activity. This, combined with Mars’ low [[gravity]] and [[Atmosphere|atmospheric pressure]], contributes to the ease with which dust is kicked up into planet-encompassing storms.<ref name=":0" />
 In addition to the interesting variation caused by the regular occurrence of dust storms, the fact that a Martian sol [[Telling Time on Mars|lasts slightly longer than an Earth day]] means that surface features will appear to move out of sight 37 minutes earlier each night.<ref name=":3" /> This both allows the observation of the entirety of the Martian surface over a relatively short period of time as well as providing the illusion that Mars rotates backwards over a period of 40 days.

@@ Line 38: / Line 38: @@
 [[File:MarsStormBeforeAfter.jpg|right|thumb|Global dust storms such as that of July 2018 can obscure even the most readily apparent features. South is up in this image.]]
-All three of these regions can be obscured by dust storms which can grow to cover the entire planet.<ref name=":0" /> These typically occur during the northern hemisphere’s summer, when the planet is closest to the Sun and additional heat increases wind activity. This, combined with Mars’ low [[gravity]] and [[Atmosphere|atmospheric pressure]] contribute to the ease with which dust is kicked up into planet-encompassing [[Dust storms|storms]].<ref name=":0" />
+All three of these regions can be obscured by [[dust storms]] which can grow to cover the entire planet.<ref name=":0" /> These typically occur during the northern hemisphere’s summer, when the planet is closest to the Sun and additional heat increases wind activity. This, combined with Mars’ low [[gravity]] and [[Atmosphere|atmospheric pressure]] contribute to the ease with which dust is kicked up into planet-encompassing storms.<ref name=":0" />
 In addition to the interesting variation caused by the regular occurrence of dust storms, the fact that a Martian sol [[Telling Time on Mars|lasts slightly longer than an Earth day]] means that surface features will appear to move out of sight 37 minutes earlier each night.<ref name=":3" /> This both allows the observation of the entirety of the Martian surface over a relatively short period of time as well as providing the illusion that Mars rotates backwards over a period of 40 days.

@@ Line 35: / Line 35: @@
 Early observers theorized that the lighter areas on Mars were continents, and as such they were given names associated with land or plains: ''Elysium Planitia, Arabia Terra, [[Hellas Planitia]]'', and ''Amazonis Planitia.''<ref name=":3" />
-Similarly, the darker regions, or albedo markings, were thought to be seas or large patches of vegetation.<ref name=":0" /><ref name=":3" /> These markings can appear to morph in size and shape due to changes in atmospheric dust, a phenomenon which was interpreted by early astronomers as resulting from Martian rainfall cycles. Somewhere between four and ten of these dark patches can be easily observed with the help of a telescope, while additional experience may allow the viewer to distinguish up to twenty.<ref name=":0" /> Portions of Valles Marineris and Olympus Mons are included within this category.<ref name=":0" />
+Similarly, the darker regions, or albedo markings, were thought to be seas or large patches of vegetation.<ref name=":0" /><ref name=":3" /> These markings can appear to morph in size and shape due to changes in atmospheric dust, a phenomenon which was interpreted by early astronomers as resulting from Martian rainfall cycles. Somewhere between four and ten of these dark patches can be easily observed with the help of a telescope, while additional experience may allow the viewer to distinguish up to twenty.<ref name=":0" /> Portions of [[Valles Marineris]] and [[Olympus Mons]] are included within this category.<ref name=":0" />
 [[File:MarsStormBeforeAfter.jpg|right|thumb|Global dust storms such as that of July 2018 can obscure even the most readily apparent features. South is up in this image.]]

@@ Line 2: / Line 2: @@
 [[File:HubbleMars.jpg|thumb|left|Photograph of Mars taken by the Hubble Space Telescope in 2016. Click to enlarge and view the visible features which have been labeled.]]
 [[File:Mars150x.jpg|thumb|right|Mars as it appears through a small telescope at 150x magnification.]]
-Mars constitutes the only planet in the solar system with surface features easily distinguishable from Earth—of the inner planets, Mercury’s small size and proximity to the sun make viewing exceptionally difficult, while Venus’ surface hides behind a thick layer of clouds.<ref name=":0">Landers, Z. (2019, June 15). Viewing Mars With Your Telescope—Extensive Guide. Retrieved September 15, 2019, from Telescopic Watch website: <nowiki>https://telescopicwatch.com/viewing-mars-with-telescope/</nowiki></ref>
+Mars constitutes the only planet in the solar system with surface features easily distinguishable from Earth—of the inner planets, Mercury’s small size and proximity to the Sun make viewing exceptionally difficult, while Venus’ surface hides behind a thick layer of clouds.<ref name=":0">Landers, Z. (2019, June 15). Viewing Mars With Your Telescope—Extensive Guide. Retrieved September 15, 2019, from Telescopic Watch website: <nowiki>https://telescopicwatch.com/viewing-mars-with-telescope/</nowiki></ref>
 As such, Martian surface features have long captured the imagination of astronomers, even helping lead to the longstanding popular belief of its inhabitation by extraterrestrial civilization. In 1877, Italian astronomer Giovanni Schiaparelli began mapping areas on Mars, including long, dark lines he named “channels”, or “canali."<ref>Canright, S. (2009, April 13). NASA - The “Canali” and the First Martians [Learning Materials]. Retrieved September 15, 2019, from NASA website: <nowiki>https://www.nasa.gov/audience/forstudents/postsecondary/features/F_Canali_and_First_Martians.html</nowiki></ref> Mistranslations of this word to English “canals” along with his own observations encouraged American Percival Lowell to theorize that these dark lines were the work of intelligent beings attempting to irrigate their dying planet.<ref>Milner, R. (2011, October 6). Tracing the Canals of Mars: An Astronomer’s Obsession. Retrieved September 15, 2019, from Space.com website: <nowiki>https://www.space.com/13197-mars-canals-water-history-lowell.html</nowiki></ref>
@@ Line 20: / Line 20: @@
 The apparent size of Mars can be as small as 3.5 arcseconds when farthest away (as a point of comparison, the Sun and Moon both have an angular diameter of around 30 arcminutes—1,800 arcseconds—in diameter, while Jupiter can reach 50 arcseconds at closest approach), but at its closest to Earth this number grows to anywhere between 15 and 25 arcseconds, depending on when opposition occurs.<ref name=":2" /><ref name=":3">Ventrudo, B. (2018, July 13). How to See Mars in 2018 – Cosmic Pursuits. Retrieved September 15, 2019, from Cosmic Pursuits website: <nowiki>https://cosmicpursuits.com/2183/how-to-see-mars-in-2018/</nowiki></ref><ref>Angular diameter. (2019). In ''Wikipedia''. Retrieved from <nowiki>https://en.wikipedia.org/w/index.php?title=Angular_diameter&oldid=915212148</nowiki></ref> Similarly, the apparent magnitude of Mars can reach +1.6 at its greatest separation from Earth, but at opposition the brightness increases to somewhere between -1.8 and -3.0.<ref name=":1" /><ref name=":2" />
-The range in values of apparent size and magnitude demonstrate the impact of the distance between Earth and Mars at opposition. In general, this cycle between opposition occurring at perihelion and aphelion takes 15 to 17 years.<ref name=":2" /> Mars will appear smaller at its next opposition of October 13, 2020 than it did on its previous opposition of July 27, 2018. This latter opposition was itself the closest approach of Mars since August 2003, when it and Earth were the closest they had been in 60,000 years.<ref name=":2" /> The next closest opposition will not occur until 2035.<ref name=":3" />
+The range in values of apparent size and magnitude demonstrates the impact of the distance between Earth and Mars at opposition. In general, this cycle between opposition occurring at perihelion and aphelion takes 15 to 17 years.<ref name=":2" /> Mars will appear smaller at its next opposition of October 13, 2020 than it did on its previous opposition of July 27, 2018. This latter opposition was itself the closest approach of Mars since August 2003, when it and Earth were the closest they had been in 60,000 years.<ref name=":2" /> The next closest opposition will not occur until 2035.<ref name=":3" />
 ==What features can be observed?==
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 The polar caps are perhaps the easiest feature to identify. Using a telescope of at least 50x magnification during opposition, one can make out the carbon dioxide and water ice frozen at the poles. Because of the planet’s axial tilt, only one of these poles will typically be visible at a time.<ref name=":0" />
-Early observers theorized that the lighter areas on Mars were continents, and as such they were given names associated with land or plains: ''Elysium Planitia, Arabia Terra, Hellas Planitia'', and ''Amazonis Planitia.''<ref name=":3" />
+Early observers theorized that the lighter areas on Mars were continents, and as such they were given names associated with land or plains: ''Elysium Planitia, Arabia Terra, [[Hellas Planitia]]'', and ''Amazonis Planitia.''<ref name=":3" />
 Similarly, the darker regions, or albedo markings, were thought to be seas or large patches of vegetation.<ref name=":0" /><ref name=":3" /> These markings can appear to morph in size and shape due to changes in atmospheric dust, a phenomenon which was interpreted by early astronomers as resulting from Martian rainfall cycles. Somewhere between four and ten of these dark patches can be easily observed with the help of a telescope, while additional experience may allow the viewer to distinguish up to twenty.<ref name=":0" /> Portions of Valles Marineris and Olympus Mons are included within this category.<ref name=":0" />
 [[File:MarsStormBeforeAfter.jpg|right|thumb|Global dust storms such as that of July 2018 can obscure even the most readily apparent features. South is up in this image.]]
-All three of these regions can be obscured by dust storms which can grow to cover the entire planet.<ref name=":0" /> These typically occur during the northern hemisphere’s summer, when the planet is closest to the Sun and additional heat increases wind activity. This, combined with Mars’ low gravity and atmospheric pressure contribute to the ease with which dust is kicked up into planet-encompassing storms.<ref name=":0" />
+All three of these regions can be obscured by dust storms which can grow to cover the entire planet.<ref name=":0" /> These typically occur during the northern hemisphere’s summer, when the planet is closest to the Sun and additional heat increases wind activity. This, combined with Mars’ low [[gravity]] and [[Atmosphere|atmospheric pressure]] contribute to the ease with which dust is kicked up into planet-encompassing [[Dust storms|storms]].<ref name=":0" />
-In addition to the interesting variation caused by the regular occurrence of dust storms, the fact that a Martian sol lasts slightly longer than an Earth day means that surface features will appear to move out of sight 37 minutes earlier each night.<ref name=":3" /> This both allows the observation of the entirety of the Martian surface over a relatively short period of time as well as providing the optical illusion that Mars rotates backwards over a period of 40 days.
+In addition to the interesting variation caused by the regular occurrence of dust storms, the fact that a Martian sol [[Telling Time on Mars|lasts slightly longer than an Earth day]] means that surface features will appear to move out of sight 37 minutes earlier each night.<ref name=":3" /> This both allows the observation of the entirety of the Martian surface over a relatively short period of time as well as providing the illusion that Mars rotates backwards over a period of 40 days.
-Finally, Mars’ two moons are observable with the help of more sophisticated equipment. At least an 8” telescope is required to make out Phobos.<ref name=":0" /> With its close orbit to Maras, the moon is only properly observable given a particularly challenging set of circumstances: Mars must be at or quite close to opposition; the moon itself must be sufficiently distant from the planet in order to stand out (this situation occurs roughly twice a night due to Phobos’ 7 hour, 40-minute orbital period; and an occulting bar must be placed across the eyepiece’s field lens in order to reduce the glare emanating from Mars.<ref name=":0" /> Comparatively simple to identify is Deimos, which  should be easily discernible once Mars is placed outside the field of view.
+Finally, Mars’ two moons are observable with the help of more sophisticated equipment. At least an 8” telescope is required to make out [[Phobos]].<ref name=":0" /> With its close orbit to Mars, the moon is only properly observable given a particularly challenging set of circumstances: Mars must be at or quite close to opposition; the moon itself must be sufficiently distant from the planet in order to stand out (this situation occurs roughly twice a night due to Phobos’ 7 hour, 40-minute orbital period; and an occulting bar must be placed across the eyepiece’s field lens in order to reduce the glare emanating from Mars.<ref name=":0" /> Comparatively simple to identify is [[Deimos]], which  should be easily discernible once Mars is placed outside the field of view.
 ==Other factors affecting observation==

← Older revision		Revision as of 19:57, 15 September 2019
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	==References==		==References==
	<references />		<references />
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		+	[[Category:Mars Planetary Science]]
		+	[[Category:Astronomy]]

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 ==When can Mars be seen?==
-[[File:MarsInZodiac.png|600px|thumb|left|Chart depicting the progression of Mars through the zodiac constellations at three-month intervals over a period of 10 years. Gaps in the sequence indicate when Mars is too close to the Sun to be seen.]]
+[[File:MarsInZodiac.png|thumb|left|Chart depicting the progression of Mars through the zodiac constellations at three-month intervals over a period of 10 years. Gaps in the sequence indicate when Mars is too close to the Sun to be seen.]]
 [[File:OppositionConjunction.jpg|thumb|right|Diagram illustrating the relative positions of Earth and Mars at opposition and conjunction. The two planets reach opposition roughly once every 26 months.]]
 Timing plays an essential role in viewing Mars from Earth. The differing orbits between the two planets mean that Mars enters opposition—that is, the point where it and Earth are on the same side of the Sun and therefore at their closest approach—once every 26 months.<ref name=":0" /><ref name=":1">Sparrow, G. (2013). ''Constellations: A Field Guide to the Night Sky'' (First). Quercus.</ref> For the majority of the year, Mars appears fairly small in the sky, although not so small that it is invisible to the naked eye. During a window of several months before and after opposition, however, it appears brighter and large enough to make out surface features with the help of a telescope.<ref name=":0" />
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 ==Other factors affecting observation==
-[[File:TelescopeTable.png|thumb|right|Applying filters to one's telescope will highlight the visibility of different features according to the color used.]]
+[[File:TelescopeTable.png|thumb|500px|right|Applying filters to one's telescope will highlight the visibility of different features according to the color used.]]
 The ease with which one can observe these features varies according to the equipment used. Low-quality telescopes can result in light scatter, image smearing, or an inability to focus at high power.<ref name=":0" /> On the other hand, telescopes with longer focal lengths and larger apertures will allow for larger and higher resolution images, respectively, while selecting the appropriate color filters can help highlight specific surface features.<ref name=":3" /> Increasing magnification too much, however, will result in Mars’ low-contrast features becoming less defined, and a viewer is unlikely to reap the full benefits of excessively large apertures due to poor seeing conditions.<ref name=":0" />

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 ==Other factors affecting observation==
-The ease with which one can observe these features varies according to the equipment used. Low-quality telescopes can result in light scatter, image smearing, or an inability to focus at high power [power]. On the other hand, telescopes with longer focal lengths and larger apertures will allow for larger and higher resolution images, respectively, while selecting the appropriate color filters can help highlight specific surface features [Longer]. Increasing magnification too much, however, will result in Mars’ low-contrast features becoming less defined [assuming], and a viewer is unlikely to be able to employ excessively large apertures to their full potential due to poor seeing conditions [utilize].
+[[File:MarsInZodiac.png|thumb|right|Applying filters to one's telescope will highlight the visibility of different features according to the color used.]]
 ==References==
 <references />