Showing posts with label telescope. Show all posts
Showing posts with label telescope. Show all posts
Monday, February 6, 2012
Issa Spyglass
Perhaps Heidegger was misled by his Japanese aristocrat student: Issa did not say "telescope". He was speaking of a "spyglass".
He must have waited his turn with his 3 coins - but what was he expecting to see as if near? Fuji-san?
That three-kanji combination is now archaic, but was not in 1790.
Friday, May 21, 2010
Arendt, Venus and Telescopes: Galileo or Kepler or Newton?
In Chapter VI of The Human Condition Hannah Arendt makes no distinction between the refracting telescope of Galileo and that of Kepler (let alone the Newtonian reflector.)
There is, of course, a world of difference. Galileo's "telescope" was an improved "glass" or "tube" - a spyglass - such as an artillery officer might use. He likely first constructed one using spectacle lenses.
Heidegger - when he first taught on science and instrument-makers - was not wearing spectacles.
What Galileo was reporting to Castelli was that Venus had the phases of the moon. This was a crucial defeat for geocentrism as a theory (as a fact - as opposed to mere theory - the Earth and Sun move approximately about their common center of mass - which happens to be within the radius of the Sun.)
What Kepler predicted was the transit of Venus across the face of the Sun (but it was not in fact visible in Europe that year of 1631 (and Kepler already dead) - but the transit of Mercury was.)
The next transit of Venus is June 6, 2012 after which there will not be another for more than 100 years.
What Arendt soft-pedals is that these phases of Venus and transits of the Sun were phenomena in the very sense in which that word was used by Greeks speaking of the night sky. But in Kepler's case, his telescope was not a mere spyglass: the "image" was not the "normal" view of a spyglass. Kepler used a subjective lens with a short focal length and an objective lens with a long focal length; Galileo's subjective lens was concave; Kepler's was not. Kepler's "image" was inverted - but the field of view was wider and provided eye relief - essential to those wearing spectacles. But Kepler's view of Venus would have been plagued by false colors (unlike Newton's.)
Heidegger would have noted that an early telescope maker was none other than an instrument maker. But was Galileo's inclined plane an instrument distorting the things as given?
And those who sought to be the first to name the moons of Venus?
Some of these remarks I will add as annotations at http://phil.aule-browser.com/arendt.htm
cf: Heidegger, "Die Frage nach der Technik" in Vortraege u. Aufsaetze
There is, of course, a world of difference. Galileo's "telescope" was an improved "glass" or "tube" - a spyglass - such as an artillery officer might use. He likely first constructed one using spectacle lenses.
Heidegger - when he first taught on science and instrument-makers - was not wearing spectacles.
What Galileo was reporting to Castelli was that Venus had the phases of the moon. This was a crucial defeat for geocentrism as a theory (as a fact - as opposed to mere theory - the Earth and Sun move approximately about their common center of mass - which happens to be within the radius of the Sun.)
What Kepler predicted was the transit of Venus across the face of the Sun (but it was not in fact visible in Europe that year of 1631 (and Kepler already dead) - but the transit of Mercury was.)
The next transit of Venus is June 6, 2012 after which there will not be another for more than 100 years.
What Arendt soft-pedals is that these phases of Venus and transits of the Sun were phenomena in the very sense in which that word was used by Greeks speaking of the night sky. But in Kepler's case, his telescope was not a mere spyglass: the "image" was not the "normal" view of a spyglass. Kepler used a subjective lens with a short focal length and an objective lens with a long focal length; Galileo's subjective lens was concave; Kepler's was not. Kepler's "image" was inverted - but the field of view was wider and provided eye relief - essential to those wearing spectacles. But Kepler's view of Venus would have been plagued by false colors (unlike Newton's.)
Heidegger would have noted that an early telescope maker was none other than an instrument maker. But was Galileo's inclined plane an instrument distorting the things as given?
And those who sought to be the first to name the moons of Venus?
Some of these remarks I will add as annotations at http://phil.aule-browser.com/arendt.htm
cf: Heidegger, "Die Frage nach der Technik" in Vortraege u. Aufsaetze
Sunday, May 9, 2010
Gutenberg and Spectacles
Arendt in The Human Condition, Chapter VI, singles out the Reformation, global navigation and the combination of the telescope as technical instrument and astrophysics as "universal" science.
Any reader might ask why not spectacles and the printing press? When the early phenomenologists adopted the slogan "To the things themselves!", no one was expected to be excluded by having to rely on spectacles: phenomenology was not exclusively or primarily focused on perception and appearances.
In one early text, "Phenomena" are roughly what we would call the constellations visible in the Mediterranean sky - a sky somewhat different from ours as the northern celestial pole was not Polaris as it is today, some two millenia later.
A more important phenomenon is the "moon illusion" as it is not dependent on either telescope or spectacles. This illusion need not be subsumed under issues of apparent numerical measure. It is quite possible that Arendt was not aware of the illusion and how it was resolved - the nature of this appearance, if you will - by science and critical dialogue.
In the arc of the sky, the full moon, high in a winter sky, subtends less than a single degree of arc - about the width of your little pinkie extended above you at arms length. Call this by some neologism such as "lunar-spatial-form-in-high-sky-hand" for some non-numerical astronomy. The rising full moon at the horizon appears to be - is said to be - much larger. If the high moon is a "dime-size" then the rising moon is a "nickel-size" - or sleeve-button-sized versus front-button-sized, to address Heidegger's numeric phobia. Pupil-of-lion versus iris-of-lion. What you will.
The telescope is another matter: the "sickle" Venus is larger in the field of a given telescope than the "full" Venus.
At the time Arendt was writing - during the 1950's - there was no star that appeared larger when in focus at high-magnification within a given star-pattern or asterism than when at low magnification in that same field. This is not so for a planet, a cluster or a nebula. With allowance for the distinct differences between the resolved image at optical limit in a refractor and in a reflector telescope, stars remain "points" of light. Only recently has the "surface of a star" been explored - other than the sun.
What was critical was the discovery that so many stars are in fact double stars and some even triple. To Herschel we owe the confirmation that true binary stars - not virtual or "optical" apparent doubles (one star appearing near another (only due to our relative alignment of star-A and star-B from earth at some point in her orbit) - obeyed Newtonian mechanics (to a good approximation given his instruments.)
Our understanding of our solar system is that it might more readily have been a binary arrangement of a yellow star with a smaller star - perhaps a brown dwarf comprised of what today are our four gas-giant planets. Our sun likely began in a cluster of stars: the fate of the solar dust ring was to be a mix of rocky planets, asteroids, gas planets, icy debris and residual dust.
It is not an illusion that Venus appears larger in one phase than in another. Nor does it require Arendt's "Archimedean" standpoint to think about this. Insight alone will not resolve this - did not resolve this.
The moon illusion is a critical absence in Chapter VI of Arendt's book - as much are the concepts of acceleration, limit, group and symmetry - not to mention the orbit of Mercury.
If only Arendt had written a book on Emmy Noether, Edith Stein and the destiny of the thinking woman at Goettingen!
see: Dorian Cairns recall of Husserl on near, far and astronomy.
also see: Sonja Kovalevsly (Sofia Kovalevskaya); Sophie Germain
more recently: Maria Skłodowska, Julia Robinson, Louise Volders
among philosophers: Susanne Langer, Susan Stebbing, E. Anscombe, Philippa Foot, Iris Murdoch
Any reader might ask why not spectacles and the printing press? When the early phenomenologists adopted the slogan "To the things themselves!", no one was expected to be excluded by having to rely on spectacles: phenomenology was not exclusively or primarily focused on perception and appearances.
In one early text, "Phenomena" are roughly what we would call the constellations visible in the Mediterranean sky - a sky somewhat different from ours as the northern celestial pole was not Polaris as it is today, some two millenia later.
A more important phenomenon is the "moon illusion" as it is not dependent on either telescope or spectacles. This illusion need not be subsumed under issues of apparent numerical measure. It is quite possible that Arendt was not aware of the illusion and how it was resolved - the nature of this appearance, if you will - by science and critical dialogue.
In the arc of the sky, the full moon, high in a winter sky, subtends less than a single degree of arc - about the width of your little pinkie extended above you at arms length. Call this by some neologism such as "lunar-spatial-form-in-high-sky-hand" for some non-numerical astronomy. The rising full moon at the horizon appears to be - is said to be - much larger. If the high moon is a "dime-size" then the rising moon is a "nickel-size" - or sleeve-button-sized versus front-button-sized, to address Heidegger's numeric phobia. Pupil-of-lion versus iris-of-lion. What you will.
The telescope is another matter: the "sickle" Venus is larger in the field of a given telescope than the "full" Venus.
At the time Arendt was writing - during the 1950's - there was no star that appeared larger when in focus at high-magnification within a given star-pattern or asterism than when at low magnification in that same field. This is not so for a planet, a cluster or a nebula. With allowance for the distinct differences between the resolved image at optical limit in a refractor and in a reflector telescope, stars remain "points" of light. Only recently has the "surface of a star" been explored - other than the sun.
What was critical was the discovery that so many stars are in fact double stars and some even triple. To Herschel we owe the confirmation that true binary stars - not virtual or "optical" apparent doubles (one star appearing near another (only due to our relative alignment of star-A and star-B from earth at some point in her orbit) - obeyed Newtonian mechanics (to a good approximation given his instruments.)
Our understanding of our solar system is that it might more readily have been a binary arrangement of a yellow star with a smaller star - perhaps a brown dwarf comprised of what today are our four gas-giant planets. Our sun likely began in a cluster of stars: the fate of the solar dust ring was to be a mix of rocky planets, asteroids, gas planets, icy debris and residual dust.
It is not an illusion that Venus appears larger in one phase than in another. Nor does it require Arendt's "Archimedean" standpoint to think about this. Insight alone will not resolve this - did not resolve this.
The moon illusion is a critical absence in Chapter VI of Arendt's book - as much are the concepts of acceleration, limit, group and symmetry - not to mention the orbit of Mercury.
If only Arendt had written a book on Emmy Noether, Edith Stein and the destiny of the thinking woman at Goettingen!
see: Dorian Cairns recall of Husserl on near, far and astronomy.
also see: Sonja Kovalevsly (Sofia Kovalevskaya); Sophie Germain
more recently: Maria Skłodowska, Julia Robinson, Louise Volders
among philosophers: Susanne Langer, Susan Stebbing, E. Anscombe, Philippa Foot, Iris Murdoch
Sunday, May 2, 2010
The Human Condition Chapter VI "World Alienation"
When Harry Frankfurt published his book "Truth" he may have been thinking of this book.
Chpater VI of The Human Condition opens with a quote from Kafka.
The opening section of the chapter is "World Alienation", which I quote:
Initially Galileo's importance was to the military - for the angle at which to set a canon for greatest distance. Galileo's improved telescope was a boon for the artillery and the tactical commander.
But was the invention of the telescope on a par with global navigation and the Reformation? There she is almost certainly mistaken as we can see with the continued rejection of Darwin based on the age of the sun until Gamow, Hoyle and others had explained that the Sun is not oxidizing a fuel (and so can be more than 5000 years old and not have "burned up" its own mass as fuel.)
What was important was the inclined plane experiment and the concept of acceleration seen in terms of distance and time. Next in order may be Lavoisier defeating Phlogiston by experiment.
It is not that I have an experimental bias - far from it.
Arendt repeats the old saw that Kopernik had no great impact (spread by another popularizer without regard to the historical facts: the documents, once reviewed by an historian of ideas, now show otherwise.)
What is worse is her sheer ignorance on so many historical matters critical to any phenomenological contribution to astronomy and modes of experience in natural science.
The solution is to present in adequate layout her texts - both the 1st and 2nd edition ( the 1st edition has a worthless index) and just ignore the introduction pasted onto the 2nd Ed.
Geophysics: 1956 marks the major break-through in plate techtonics.
Evolution: Arendt conflates the evolution of the earth with that of our species in one and the same sentence.
Arendt conflates all relativism with Einsteinian relativity.
Arents conflates mathematics and mathematical physics (wholly ignorant of Bryn Mawr's Emmy Noether and the role of non-arithmetic symmetries and groups to GTR.) See Heidegger on science as classification, measurement and calculation.
Arendt conflates mathematical physics with experimental physics across both celestial mechanics and particle physics.
Arendt shows no sign of knowing what Maxwell had achieved (she repeats Heideger's claim which he made on television of what can no longer be comprehended.)
Arendt conflates "fixed point" with ":Archimedian point" with Mach on no privileged point.
Arendt repeats misconstruals of Galileos' own views.
Arendt appears not to know that two orbiting masses orbit about their commonpoint of mass (would she have known where this point lies?)
Arendt appears not to know that Plato knew the view of Pythagorous that Hesperus is Phosphorus.
Arendt seems to believe that uranium does not occur naturally (and so was ignorant of the actual WORK done by Pierre and Marie Curie with pitchblende.)
The 1st ed. has no reference to Heidegger but is riddled with almost direct quotes from him and includes the capitalization of Being.
Arendt appears not to know the basis for Einstein's Nobel prize (see her comments on matter and energy.)
Arendt appears not to have read books which she quotes based on her remarks about relativity: the role of invariants is lost on her.
Arendt seems unaware of how non-Euclidean geometries arose (this is not a matter of arithmetic, measurement or calculations but an issue which her Plato would also have acknowledged concerning a premise.)
The work of a seminal thinker.
Arendt was as anthropocentric as Heidegger- perhaps even more so. The use of her word "creature" could mislead the naive reader. See Heidegger on animals.
Arendt has amassed in a single chapter such a wealth of falsehoods, false dichotomies, fallacies, suppressed premises, pointless polemics, deliberate distortions and yet not a reference to her source: Heidegger.
As a philosopher she fails to distinguish instrumentalism, pragmatism, mechanism, physicalism, naturalism - all in the Heidegger tradition (see Heidegger on Erich Frank.)
Heidegger never sat his exams in science and math. Arendt was a political ignoramus before 1930. She bungled her work as a commentator on some of the most appalling events and outcomes of the 20th Century and she utterly bungles her learned assessment of the "modern age".
Any poet who has ever looked at the moon through a telescope will know what I mean.
With regard to Galileo, even an a world with no moon (no tides - so likely no tidal pools so likely no terrestrial life) and with a thick atmostphere with no view of a sun - and especially a foggy world in need of telescopes and accurate artillery - would might have an experiment in acceleration of lead shot on a smooth inclined plane, navigation using the polarization of light and Maxwell.
The answer is to layout some of her most outrageous claims in plain view in web pages designed to facilitate the documentation of bullsh*t. This I will get rolling at http://aule-browser.com/
The reviews of the book at SEP, IEP and wikipedia should bring all of those encyclopedist efforts into question -especially the "peer-reviewed" bullsh*t. Truth is worth the effort and the work required - and collaboration, not singular individuals as is the model at SEP and IEP.
see Jocelyn Benoist and others on the triumph of Heideggerian bullsh*t as philology, etymology and classical scholarship in French philosphy. Theology in disguise is a dark travelling companion.
Humor: Arendt also warns that we may explode the entire planet. Luckily the CERN collider was not named in her honor.
Arendt seems to think the phenomenology of "heaviness" is impugned by distinguishing weight from mass. She was not a student of Stumpf or Lipps but did spend a few months attending Husserl's lectures (himself a former assistant to Weierstrass and influenced by Bolzano who is something of a parent to "modern" science and to the theory of the militarist state.)
Is there any indication that Arendt ever read Mach, Poincaré or Bolzano? Was knowing Aristotle in the Greek a basis for a critique of twentieth century physics let alone mathematical physics in the western world? If she only knew Mahomet in Arabic, it might be enough: see the Fatwa that helped end new science in the Islamic world. Compare the view of the Vatican on astronomy during the past 150 years and its current contributions to astronomy.
See: Robert Musil dissertaion on Ernst Mach
See: Arendt on the watchmaker.
Truly curious: Arendt quotes Russell from a secondary source.
Fact: in a letter to Heidegger Arendt claims to read Merleau-Ponty only in 1972.
For a defence of Descartes see various. On the claim that the early is superior to the later, see Heidegger. Compare this view to Locke as a Cartesian versus Hume (Locke being "prior" to Hume as were Parmenides and Heraklit prior to Plato and Aristotle. CF Heidegger on Aristotle's physics in Wegmarken/Pathmarks)
Humor: the great collection (assemblage) of Seba becomes the first museum (Kunsthaus) of Peter I's Saint Petersburg. Linnaeus follows shortly thereafter. See the role of classification and the Cepheid variables in the discoveries of Edwin Hubble.
Remark: see the evidence for dark matter with regard to the role of patient, observant women in astronomy.
A seminal thinker and seed spilled on the ground. Or was it on the bench?
Chpater VI of The Human Condition opens with a quote from Kafka.
The opening section of the chapter is "World Alienation", which I quote:
Three great events stand at the threshold of the modern age and determine its character:The 3rd great moment is the telescope in astronomy (we ignore that the events that matter in the early history of observational astronomy concern establishing certain facts by description and by drawings prior to testing any hypotheses.)
...
the invention of the telescope and the development of a new science that considers the nature of the earth from the viewpoint of the universe.
Initially Galileo's importance was to the military - for the angle at which to set a canon for greatest distance. Galileo's improved telescope was a boon for the artillery and the tactical commander.
But was the invention of the telescope on a par with global navigation and the Reformation? There she is almost certainly mistaken as we can see with the continued rejection of Darwin based on the age of the sun until Gamow, Hoyle and others had explained that the Sun is not oxidizing a fuel (and so can be more than 5000 years old and not have "burned up" its own mass as fuel.)
What was important was the inclined plane experiment and the concept of acceleration seen in terms of distance and time. Next in order may be Lavoisier defeating Phlogiston by experiment.
It is not that I have an experimental bias - far from it.
Arendt repeats the old saw that Kopernik had no great impact (spread by another popularizer without regard to the historical facts: the documents, once reviewed by an historian of ideas, now show otherwise.)
What is worse is her sheer ignorance on so many historical matters critical to any phenomenological contribution to astronomy and modes of experience in natural science.
The solution is to present in adequate layout her texts - both the 1st and 2nd edition ( the 1st edition has a worthless index) and just ignore the introduction pasted onto the 2nd Ed.
Geophysics: 1956 marks the major break-through in plate techtonics.
Evolution: Arendt conflates the evolution of the earth with that of our species in one and the same sentence.
Arendt conflates all relativism with Einsteinian relativity.
Arents conflates mathematics and mathematical physics (wholly ignorant of Bryn Mawr's Emmy Noether and the role of non-arithmetic symmetries and groups to GTR.) See Heidegger on science as classification, measurement and calculation.
Arendt conflates mathematical physics with experimental physics across both celestial mechanics and particle physics.
Arendt shows no sign of knowing what Maxwell had achieved (she repeats Heideger's claim which he made on television of what can no longer be comprehended.)
Arendt conflates "fixed point" with ":Archimedian point" with Mach on no privileged point.
Arendt repeats misconstruals of Galileos' own views.
Arendt appears not to know that two orbiting masses orbit about their commonpoint of mass (would she have known where this point lies?)
Arendt appears not to know that Plato knew the view of Pythagorous that Hesperus is Phosphorus.
Arendt seems to believe that uranium does not occur naturally (and so was ignorant of the actual WORK done by Pierre and Marie Curie with pitchblende.)
The 1st ed. has no reference to Heidegger but is riddled with almost direct quotes from him and includes the capitalization of Being.
Arendt appears not to know the basis for Einstein's Nobel prize (see her comments on matter and energy.)
Arendt appears not to have read books which she quotes based on her remarks about relativity: the role of invariants is lost on her.
Arendt seems unaware of how non-Euclidean geometries arose (this is not a matter of arithmetic, measurement or calculations but an issue which her Plato would also have acknowledged concerning a premise.)
The work of a seminal thinker.
Arendt was as anthropocentric as Heidegger- perhaps even more so. The use of her word "creature" could mislead the naive reader. See Heidegger on animals.
Arendt has amassed in a single chapter such a wealth of falsehoods, false dichotomies, fallacies, suppressed premises, pointless polemics, deliberate distortions and yet not a reference to her source: Heidegger.
As a philosopher she fails to distinguish instrumentalism, pragmatism, mechanism, physicalism, naturalism - all in the Heidegger tradition (see Heidegger on Erich Frank.)
Heidegger never sat his exams in science and math. Arendt was a political ignoramus before 1930. She bungled her work as a commentator on some of the most appalling events and outcomes of the 20th Century and she utterly bungles her learned assessment of the "modern age".
Any poet who has ever looked at the moon through a telescope will know what I mean.
With regard to Galileo, even an a world with no moon (no tides - so likely no tidal pools so likely no terrestrial life) and with a thick atmostphere with no view of a sun - and especially a foggy world in need of telescopes and accurate artillery - would might have an experiment in acceleration of lead shot on a smooth inclined plane, navigation using the polarization of light and Maxwell.
The answer is to layout some of her most outrageous claims in plain view in web pages designed to facilitate the documentation of bullsh*t. This I will get rolling at http://aule-browser.com/
The reviews of the book at SEP, IEP and wikipedia should bring all of those encyclopedist efforts into question -especially the "peer-reviewed" bullsh*t. Truth is worth the effort and the work required - and collaboration, not singular individuals as is the model at SEP and IEP.
see Jocelyn Benoist and others on the triumph of Heideggerian bullsh*t as philology, etymology and classical scholarship in French philosphy. Theology in disguise is a dark travelling companion.
Humor: Arendt also warns that we may explode the entire planet. Luckily the CERN collider was not named in her honor.
Arendt seems to think the phenomenology of "heaviness" is impugned by distinguishing weight from mass. She was not a student of Stumpf or Lipps but did spend a few months attending Husserl's lectures (himself a former assistant to Weierstrass and influenced by Bolzano who is something of a parent to "modern" science and to the theory of the militarist state.)
Is there any indication that Arendt ever read Mach, Poincaré or Bolzano? Was knowing Aristotle in the Greek a basis for a critique of twentieth century physics let alone mathematical physics in the western world? If she only knew Mahomet in Arabic, it might be enough: see the Fatwa that helped end new science in the Islamic world. Compare the view of the Vatican on astronomy during the past 150 years and its current contributions to astronomy.
See: Robert Musil dissertaion on Ernst Mach
See: Arendt on the watchmaker.
Truly curious: Arendt quotes Russell from a secondary source.
Fact: in a letter to Heidegger Arendt claims to read Merleau-Ponty only in 1972.
For a defence of Descartes see various. On the claim that the early is superior to the later, see Heidegger. Compare this view to Locke as a Cartesian versus Hume (Locke being "prior" to Hume as were Parmenides and Heraklit prior to Plato and Aristotle. CF Heidegger on Aristotle's physics in Wegmarken/Pathmarks)
Humor: the great collection (assemblage) of Seba becomes the first museum (Kunsthaus) of Peter I's Saint Petersburg. Linnaeus follows shortly thereafter. See the role of classification and the Cepheid variables in the discoveries of Edwin Hubble.
Remark: see the evidence for dark matter with regard to the role of patient, observant women in astronomy.
A seminal thinker and seed spilled on the ground. Or was it on the bench?
Monday, April 26, 2010
Mercury - and Mercury, again.
I take it as a given that most western Europeans have never paused to see Mercury in the sky.
If asked, most could not tell you where to look for Mercury (some would now start on the internet.)
If offered a clue: "What about sunrise and sunset?"
Or even more explicit: "What about sunrise and sunset? Before which or after which?"
Some very few might suggest a deep, shallow mineshaft in daylight - or a full solar eclipse.
Simply: look for Mercury sometimes after sunset in the west or at other times before sunrise in the east.
But why named for Hermes, the messenger? What are these comings and goings of Mercury while Venus and Apollo's sun-chariot are so much more regular and steady?
And what of the appearance of Mercury? IF you were to see Mercury with the aid of a telescope, of what might you become aware? [here, see Epictetus]
Suppose that I show you Mercury in a telescope ... here are the variants for this Anschaung that come to mind (and arise if I set up more than one telescope along the road for neighbours and passers-by.)
Subjective: (holding the subjective lens)
1) 45deg mirror (or 90deg prism)
2) Amici prism
3) straight tube extender
Objective
1) mirror (various overall designs and configurations from simple Newtonian to highly modified)
2) lens (as in the typical "Galilean" telescope)
Mount
free-moving (likely a reflector, but also a small refractor on a ball-head mount)
altitude-azimuth
German equatorial
computerized variants of any of the above three
star-gazer
a digital identifier of the stars, planets and or asterisms at which it is aimed
activity
hand tracking
motor-tracking
the above in combination
variants: monocular or binocular options apply in the above to objective, subjective and star-gazer device.
What will be seen: (general characterization)
reflector - a little fuzzy but with good colour (expecially the planets Mars, Jupiter, Saturn)
refractor - may be quite sharp image, but may have violet fringe if not using hydrogen filter
What will be seen: (shape)
The two inner planets, Venus and Mercury, are subject to what might be described as "lunar" phases: they are moon-like in appearance.
Sceptic: how do you know it is not a star?
Answer: under magnification it increases in size as a disk: many stars under magnification do not change their "aspect" notably or else may even reveal themselves to be double or even triple stars (and if the tube is tapped lightly, trace clear distinct sinusoidal paths in which each star is clearly distinguished by a fine "parallel" path with the others - a case of movement in observation)
Richer answer: it will visibly have moved against the starry background by tomorrow
Jupiter answer: watch the weather change and moons appear and shadows pass over its face.
But not Veuns and Mercury. Every 16 years Mars displays its ice caps. But not Venus and Mercury.
Where in lies the scientific/social division-of-labor in the apperception of Mercury.
The observer tends to need to be coached: "Yes, bigger in the view than the star I just showed you - but how would you describe that shape? What does it remind you of?"
Next task: explain away the violet halo.
Next task: explain why the image is inverted up-side down or mirror-reversed.
"See, in this telescope the crescent of Mercury is 'looking down' towards where the sun has set - see?"
"Notice that in this telescope Mercury is 'looking up to the right' but the sun has set down to the left... Let's look at the cresent moon up there in each telecope ... and compare what you see in the scope to what you see with these binoculars ..."
And where is the cresent moon if it is just after sunset? I hope you do not look up, or worse, east ... And which way is it facing ...
Any introductory course in college astronomy should be paired with a course in philosophy. Ditto for botany. Chemistry. Any introductory college course in physics should require one evening learning to look at the night sky. Otherwise how shall we reply to the attacks on reason, Galileo, naturalism and modernity? How else shall we defend observation over prejudice if there is no "foundation" in the actual experience of the student? Next topic: the lunar illusion and the rising full moon.
a note on mathesis in praxis: even the use of the alt-azimuth and the equatorial mounts do not - in use - require mathematics or measurements or numbers or compass points (although the equiatorial mount will be easier to use of faced north and with an angle approximately that of the latitiude of the observer's location.
If asked, most could not tell you where to look for Mercury (some would now start on the internet.)
If offered a clue: "What about sunrise and sunset?"
Or even more explicit: "What about sunrise and sunset? Before which or after which?"
Some very few might suggest a deep, shallow mineshaft in daylight - or a full solar eclipse.
Simply: look for Mercury sometimes after sunset in the west or at other times before sunrise in the east.
But why named for Hermes, the messenger? What are these comings and goings of Mercury while Venus and Apollo's sun-chariot are so much more regular and steady?
And what of the appearance of Mercury? IF you were to see Mercury with the aid of a telescope, of what might you become aware? [here, see Epictetus]
Suppose that I show you Mercury in a telescope ... here are the variants for this Anschaung that come to mind (and arise if I set up more than one telescope along the road for neighbours and passers-by.)
Subjective: (holding the subjective lens)
1) 45deg mirror (or 90deg prism)
2) Amici prism
3) straight tube extender
Objective
1) mirror (various overall designs and configurations from simple Newtonian to highly modified)
2) lens (as in the typical "Galilean" telescope)
Mount
free-moving (likely a reflector, but also a small refractor on a ball-head mount)
altitude-azimuth
German equatorial
computerized variants of any of the above three
star-gazer
a digital identifier of the stars, planets and or asterisms at which it is aimed
activity
hand tracking
motor-tracking
the above in combination
variants: monocular or binocular options apply in the above to objective, subjective and star-gazer device.
What will be seen: (general characterization)
reflector - a little fuzzy but with good colour (expecially the planets Mars, Jupiter, Saturn)
refractor - may be quite sharp image, but may have violet fringe if not using hydrogen filter
What will be seen: (shape)
The two inner planets, Venus and Mercury, are subject to what might be described as "lunar" phases: they are moon-like in appearance.
Sceptic: how do you know it is not a star?
Answer: under magnification it increases in size as a disk: many stars under magnification do not change their "aspect" notably or else may even reveal themselves to be double or even triple stars (and if the tube is tapped lightly, trace clear distinct sinusoidal paths in which each star is clearly distinguished by a fine "parallel" path with the others - a case of movement in observation)
Richer answer: it will visibly have moved against the starry background by tomorrow
Jupiter answer: watch the weather change and moons appear and shadows pass over its face.
But not Veuns and Mercury. Every 16 years Mars displays its ice caps. But not Venus and Mercury.
Where in lies the scientific/social division-of-labor in the apperception of Mercury.
The observer tends to need to be coached: "Yes, bigger in the view than the star I just showed you - but how would you describe that shape? What does it remind you of?"
Next task: explain away the violet halo.
Next task: explain why the image is inverted up-side down or mirror-reversed.
"See, in this telescope the crescent of Mercury is 'looking down' towards where the sun has set - see?"
"Notice that in this telescope Mercury is 'looking up to the right' but the sun has set down to the left... Let's look at the cresent moon up there in each telecope ... and compare what you see in the scope to what you see with these binoculars ..."
And where is the cresent moon if it is just after sunset? I hope you do not look up, or worse, east ... And which way is it facing ...
Any introductory course in college astronomy should be paired with a course in philosophy. Ditto for botany. Chemistry. Any introductory college course in physics should require one evening learning to look at the night sky. Otherwise how shall we reply to the attacks on reason, Galileo, naturalism and modernity? How else shall we defend observation over prejudice if there is no "foundation" in the actual experience of the student? Next topic: the lunar illusion and the rising full moon.
a note on mathesis in praxis: even the use of the alt-azimuth and the equatorial mounts do not - in use - require mathematics or measurements or numbers or compass points (although the equiatorial mount will be easier to use of faced north and with an angle approximately that of the latitiude of the observer's location.
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