{"id":674,"date":"2014-12-09T21:02:00","date_gmt":"2014-12-09T21:02:00","guid":{"rendered":"http:\/\/dev.austrinus.com\/?p=674"},"modified":"2025-01-17T05:11:10","modified_gmt":"2025-01-17T08:11:10","slug":"astronomia-dia","status":"publish","type":"post","link":"https:\/\/austrinus.com\/en\/astronomia-dia\/","title":{"rendered":"Astronomy by day"},"content":{"rendered":"
Below you will find observational experiments that do not require optical instrumentation, possible to practice during the day. Some require a few sessions of observation and monitoring to become aware, while others merit continuous recording. All exercises are designed to simulate a total absence of astronomical knowledge, with the aim of demonstrating that it is possible to identify phenomena of this nature using only naked eye observation and reasoning.<\/div>\n
<\/div>\n
Astronomy experiments without a telescope (by day):\u00a0<\/strong><\/div>\n

1) The Sun always rises at one cardinal point and sets at the opposite point, just like the first stars at sunset and the last at dawn.\u00a0<\/strong><\/em><\/p>\n

\"ExperimentoWatch a sunrise and see where the Sun rises. Depending on your geographic location, this may be over a mountain, a plain, a river, etc., but it will always be from the same location if you see several sunrises in a row. Similarly, at the end of the day, the Sun will \u201cset\u201d at a different point, which will be the opposite point from which it appeared at sunrise, and this will invariably repeat itself as the days go by.<\/p>\n

By doing this exercise, you will not only notice that the Sun continues to "rise" at one point and "set" at the opposite point, but you will also be able to see it in the "rise" and "set" of one or more stars. When it gets dark, as sunlight becomes less and less, the stars begin to be seen; but if you look closely, you will notice that they seem to come from the same area where the Sun appeared at dawn. In the same way, when the Sun is about to appear at the next dawn, you will notice (in fact you will have noticed it all night) that these stars "set" at the opposite point, that is, in the same area where the Sun set at the previous dusk.<\/p>\n

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Preliminary conclusion: Cardinal points<\/strong><\/em>. This exercise, carried out over a few days, will quickly lead you to the conclusion that the main daytime celestial body (the Sun) and the numerous stars that can be seen shortly after sunset and just before dawn, follow an equivalent pattern of "rising" and "setting" sectors. This is a first approximation to the concept of cardinal points, the simplest way of orienting oneself in the sky.<\/p>\n<\/blockquote>\n

<\/p>\n

2) The Sun minimally varies the exact position from which it rises daily.<\/strong><\/em><\/p>\n

\"ExperimentoIn the example above, a few days are enough to notice that the Sun appears from the same point at its "rise" and sets from the same opposite point at its "set". But taking this exercise a little further, and if you intend to use a simple device to determine the exact position of the Sun (something as rudimentary as a\u00a0geometric cross<\/a>), it can be seen that the Sun varies its rising position only slightly over time. To notice it clearly, a follow-up of at least 1 month would be necessary, but going much further, say from 6 months to 1 year, not only can this variation be observed, but it also seems to "stop" at a moment, and then go back.<\/p>\n

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Preliminary conclusion: Variation in the position of the Sun<\/strong><\/em>Depending on whether the shift is observed for about 1 month, or more extensively for more than 6 months, the observer can conclude that the sunrises and sunsets are not something perfectly "synchronized" or repetitive, but rather that they experience a variation, which (if extensive monitoring was done) can actually be determined as a cycle, since the shift advances, stops and goes backwards, but always moves within the same range.<\/p>\n<\/blockquote>\n

3) The Sun gradually describes a shorter or longer "trace" in the sky, and consequently its maximum height above the horizon will vary.<\/strong><\/em><\/p>\n

\"ExperimentoRelated to the previous exercise, the Sun's positional variations during its rise also imply 2 possible phenomena to be observed: that the path or trajectory that it describes in the sky will be shorter or longer (depending on the moment in which the variations begin to be followed), so the maximum height it reaches in the sky will be higher or lower. To appreciate this difference in height, a very rudimentary instrument such as a geometric cross is also needed, and at least 1 month of monitoring to appreciate differences. The appreciation of a shorter or longer path is directly related to the "length of the day", that is, the time it takes for the Sun to rise and set. To determine this, a rudimentary technique can also be used, such as measuring the shadow (related to the 3rd experiment), but if you want to do it yourself, you can do it yourself.\u00a0trap<\/em>, you can simply use a watch to notice the different duration (if the tracking is brief it will only be variations of seconds or a few minutes).<\/p>\n

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Preliminary conclusion: Different length of the day and existence of seasons<\/strong><\/em>The longest or shortest trajectory, complemented by a greater or lesser height above the horizon, respectively, allows to identify a longer or shorter day length, which, again, in the case of an extensive monitoring (6 months to 1 year) allows to determine it as a cycle that moves in a range of maximum and minimum height (and a maximum and minimum "trace"). Additionally, depending on the length of the experiment and climatic conditions of the observation site, the periods of longest and shortest day length can be associated with moments of greatest heat and cold, respectively.<\/p>\n<\/blockquote>\n

<\/p>\n

4) The length of the solar shadow varies throughout the day and allows it to be sectioned based on these differences.<\/strong><\/em><\/p>\n

\"ExperimentoAlways related to the previous experiences, this discovery is also feasible in a short or long follow-up. It is enough to use a primitive element (such as a stick stuck into a surface) to notice that its shadow varies at different times of the day, from sunrise to sunset. In an extensive follow-up, it can also be noted that this shadow becomes longer or shorter as the months go by, but the pattern of the shadow "pointing" in a specific direction at a given moment of the day is always repeated. This lays the foundation not for an astronomical discovery, but for a practical application, which is the creation of a time measurement system: a sundial.<\/p>\n

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Preliminary conclusion: Shadow-based time measurement system<\/strong><\/em>. While in the previous exercise I left open the possibility of "cheating", in this one the fundamental thing is not to do it, in order to achieve the objective. An accurate sundial requires some mathematics and precise measurements, but as a first approximation it is enough to equitably section the passage of the solar shadow through some area around the stuck rod (such as a drawn circle).<\/p>\n<\/blockquote>\n

5) Both the Sun and the Moon always "transit" through the same "band" of the sky.<\/strong><\/em><\/p>\n

\"ExperimentoAlthough the experience of following the "track" and noticing that the position of rising and setting are always opposite can already verify this statement on its own, this is the concrete confirmation of this phenomenon. Not only the Sun, but also the Moon, when one has the opportunity to see it during the day, describe a path that always moves along the same band or region of the sky, which although it is not an exact line, always corresponds to the same range. To determine this exact "range" it is necessary to follow the Sun for a long time (at least for 1 year), but for practical purposes, the transit of the Sun and the Moon through that specific zone is verifiable after a few days.<\/p>\n

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Preliminary conclusion: Imaginary ecliptic line<\/strong><\/em>. Well known in amateur astronomy, the ecliptic is the imaginary line through which the Sun, the Moon and other objects transit (to be reviewed later), whose altitude will be determined by the geographical location of the observer, but without prejudice to this factor, the The ecliptic is a reference area to know where the main daytime celestial bodies will pass.<\/p>\n<\/blockquote>\n

<\/p>\n

6) The Moon takes about 28 days to complete a cycle of phases.<\/strong><\/em><\/p>\n

\"ExperimentoAlthough it is not necessary to understand yet (imagining nothing in astronomy) why the lunar phases occur, an observer can do the simple exercise of contemplating how this object is seen illuminated in different proportions each day, illuminating more or less each time, until reach the same starting position and start again. By listing the days based on how many times the Sun has completed the rising and setting routine, the observer can determine how long it takes for the Moon to return to the same phase originally observed, which will result in about 28 days. To determine this, a little more than 1 month of monitoring is needed, although it is assumed that the observer does not know from the start the information on how long a complete lunation takes.<\/p>\n

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Preliminary conclusion: Determination of the phases of the Moon<\/strong><\/em>. The Moon can be seen at night or day, depending on the date, and tracking its phases is quite simple. Determining the period of lunation is only a first step in solving the most important question: why do the phases occur? For which it is necessary to know a few more things as we progress through these experiences.<\/p>\n<\/blockquote>\n

7) The Moon appears in a more "rearward" position in the sky every day.<\/strong><\/em><\/p>\n

\"ExperimentoAs one follows the Moon in the previous exercise, it is quickly possible to notice that the Moon appears to be more delayed each day. Although this does not affect the fact that it moves in the same direction as the Sun (from the point of "rise" to the point of "set"), its daily position seen at the same instants shows it to be more delayed. This is a first step towards understanding the lunar phases and the Moon's own motion, which, although it is constant across the sky, is evident that something is "delaying" its position relative to the background of stars. It is also interesting to note, both from this and the previous experiment, that the Moon always shows the same face to the Earth, and the explanation of this requires knowing the concepts of rotation and translation.<\/p>\n

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Preliminary conclusion: Knowing the proper motion of the Moon<\/strong><\/em>The "delay" that the Moon experiences in its appearance on a daily basis is an unequivocal sign that there are different speeds involved, when this delay is observed at night: that of the\u00a0apparent movement\u00a0<\/em>of the stars with respect to the Moon's own motion. This is a first indication that the Moon is much closer than that "star background", and that it also moves independently, so that we can conclude, in a very basic way, that the Moon is moving in relation to (or around) this star background, which in turn is constantly moving, but also does so at a slower speed than the latter.<\/p>\n<\/blockquote>\n

<\/p>\n

8) The Moon describes a transit that places half of its cycle above the Earth's plane with respect to the Sun, and the other half below that plane.<\/strong><\/em><\/p>\n

\"ExperimentoThe Moon, as already mentioned in a previous exercise, transits along the ecliptic line just like the Sun. But it is not subject to an exact line, but rather moves within a range within that band. If one follows the trajectories of the Sun and the Moon extensively in the daytime sky, equipped with some rudimentary device that allows one to compare their positions, one will notice that the Moon passes "above" or "below" the Sun, further back or further ahead, without ever crossing, except on rare occasions; therein lies the maximum expression of this phenomenon, which occurs during a\u00a0solar eclipse<\/strong><\/em>, when the Sun is exactly in conjunction with the Moon, or in a\u00a0lunar eclipse<\/strong><\/em>, when the Moon crosses the shadow cone cast by the Earth. Since these crossings happen only every so often, solar or lunar eclipses do not occur every month. This exercise is the least feasible to verify in its maximum expression (an eclipse) because it can take several months for one to occur, but the lunar deviation in its trajectory can be measured.<\/p>\n

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Preliminary conclusion: Deviation of the Moon with respect to the ecliptic line<\/strong><\/em>. With these measurements, although they require more reasoning, one can know the "drift" of the Moon in its passage through that "imaginary band" (In practice the lunar orbital plane is inclined 5\u00b0 with respect to the ecliptic<\/em>) and how this implies that we do not have a Sun-Moon conjunction, or a passage of the Moon through the Earth's shadow cone, every month (although saying "shadow cone<\/em>\u00bb involves knowing the relative position of the Earth, the Sun and the Moon in space. Using mathematics, it is even possible to predict when the next eclipse will occur, if the trajectory and displacement variables in relation to the ecliptic are known precisely.<\/p>\n<\/blockquote>\n

9) There are planets like Venus or Mercury that move relative to the "fixed" stars of sunrise\/sunset, but always in apparent proximity to the Sun.<\/strong><\/em><\/p>\n

\"ExperimentoThis exercise assumes that the observer, in addition to following the Sun and the Moon during daylight hours, has also paid attention to other objects that are not observed fixed in relation to the "star background." There are 5 planets visible to the naked eye, but at sunrise\/sunset the most likely to be seen are Mercury and Venus (which for the purposes of this exercise will only be considered as a "fainter object" and a "brighter object"). To determine that these objects really move independently, a follow-up is needed that can last several months, depending on how long it takes one to notice their own motion, and how long it takes to notice that their appearance is always in temporal proximity to the Sun (the latter can take at least a year).<\/p>\n

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Preliminary conclusion: Discovery of planets associated with the Sun<\/strong><\/em>The etymology of "planet" means "wanderer", which is the appropriate name for an object that appears to wander through an area of space, independent of the\u00a0apparent movement<\/em>\u00a0of "fixed" stars. These two objects, once identified as "planets," come to form a special category along with the Sun and the Moon, since their motion gives them a distinguishable quality as celestial bodies. Explaining their apparent closeness to the Sun requires understanding their relative position in space.<\/p>\n<\/blockquote>\n

<\/p>\n

10) The Sun, the Moon, Venus, Mercury or any daytime\/nighttime star close to the horizon appear "distorted."<\/strong><\/em><\/p>\n

\"ExperimentoTo see this, it doesn't take much follow-up, but rather to notice what happens to any of these objects when they are seen near the horizon. When the Sun is about to "set," it may appear blurry, orange, or oval-shaped; the Moon may appear orange and strange. While this does not occur in the same way with any distant daytime object (e.g. a mountain, a forest), it is noticeable that any object on the horizon will appear "paler" or "hazier" than those close by. While this does not immediately indicate the presence of an atmosphere or the curvature of the Earth, it does give a clue that "something" invariably affects the vision of a distant object, due to a property of the observation site and not of the observed object itself.<\/p>\n

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Preliminary conclusion: Knowing the Earth's atmosphere<\/strong><\/em>. While this determination is difficult by mere observation, everyday life offers several analogies to atmospheric interference on distant objects. Just as the presence of more layers of atmospheric gas hinders the vision of low objects on the horizon, when observing any object underwater it will always look more blurry, because the masses of water cloud and interfere with the passage of light.<\/p>\n<\/blockquote>","protected":false},"excerpt":{"rendered":"

Below you will find observational experiments that do not require optical instrumentation, possible to practice during the day. Some require a few sessions of observation and monitoring to become aware, while others merit continuous recording. All exercises are designed simulating a total absence of astronomical knowledge, with the aim of demonstrating that it is possible...<\/p>","protected":false},"author":1,"featured_media":3206,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[101],"tags":[],"class_list":["post-674","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-como-observar"],"magazineBlocksPostFeaturedMedia":{"thumbnail":"https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon-150x150.jpg","medium":"https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg","medium_large":"https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg","large":"https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg","1536x1536":"https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg","2048x2048":"https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg","trp-custom-language-flag":"https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg"},"magazineBlocksPostAuthor":{"name":"Farid","avatar":"https:\/\/secure.gravatar.com\/avatar\/57e8aa07b0d16e13c8408ea413c009fc7da05f4cbb36da0d568b4235b1eaee6b?s=96&r=g"},"magazineBlocksPostCommentsNumber":false,"magazineBlocksPostExcerpt":"A continuaci\u00f3n encontrar\u00e1s experimentos observacionales que no requieren de instrumentaci\u00f3n \u00f3ptica, posibles de practicar durante el d\u00eda. Algunos requieren de pocas sesiones de observaci\u00f3n y seguimiento para advertirse, mientras que otros ameritan un registro continuo. Todos los ejercicios est\u00e1n pensados simulando una total ausencia de conocimientos astron\u00f3micos, con el objetivo de demostrar que es posible…","magazineBlocksPostCategories":["C\u00f3mo observar"],"magazineBlocksPostViewCount":2596,"magazineBlocksPostReadTime":15,"magazine_blocks_featured_image_url":{"full":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",200,150,false],"medium":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",200,150,false],"thumbnail":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon-150x150.jpg",150,150,true]},"magazine_blocks_author":{"display_name":"Farid","author_link":"https:\/\/austrinus.com\/en\/author\/farid\/"},"magazine_blocks_comment":0,"magazine_blocks_author_image":"https:\/\/secure.gravatar.com\/avatar\/57e8aa07b0d16e13c8408ea413c009fc7da05f4cbb36da0d568b4235b1eaee6b?s=96&r=g","magazine_blocks_category":"C\u00f3mo observar<\/a>","uagb_featured_image_src":{"full":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",200,150,false],"thumbnail":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon-150x150.jpg",150,150,true],"medium":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",200,150,false],"medium_large":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",200,150,false],"large":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",200,150,false],"1536x1536":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",200,150,false],"2048x2048":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",200,150,false],"trp-custom-language-flag":["https:\/\/austrinus.com\/wp-content\/uploads\/2015\/01\/astronomia-dia-icon.jpg",16,12,false]},"uagb_author_info":{"display_name":"Farid","author_link":"https:\/\/austrinus.com\/en\/author\/farid\/"},"uagb_comment_info":0,"uagb_excerpt":"A continuaci\u00f3n encontrar\u00e1s experimentos observacionales que no requieren de instrumentaci\u00f3n \u00f3ptica, posibles de practicar durante el d\u00eda. Algunos requieren de pocas sesiones de observaci\u00f3n y seguimiento para advertirse, mientras que otros ameritan un registro continuo. Todos los ejercicios est\u00e1n pensados simulando una total ausencia de conocimientos astron\u00f3micos, con el objetivo de demostrar que es posible…","_links":{"self":[{"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/posts\/674","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/comments?post=674"}],"version-history":[{"count":1,"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/posts\/674\/revisions"}],"predecessor-version":[{"id":6917,"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/posts\/674\/revisions\/6917"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/media\/3206"}],"wp:attachment":[{"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/media?parent=674"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/categories?post=674"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/austrinus.com\/en\/wp-json\/wp\/v2\/tags?post=674"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}