Observation
3C 273 is visible in May in both the northern hemisphere and southern hemispheres. It is bright enough to be observed with larger amateur telescopes. Due in part to its radio luminosity and its discovery as the first identified quasar, 3C 273's right ascension in the Fifth Fundamental Catalog (FK5) is used to standardize the positions of 23 extragalactic radio sources used to define the International Celestial Reference System (ICRS).
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“One man’s observation is another man’s closed book or flight of fancy.”
—Willard Van Orman Quine (b. 1908)
“I know not anything more pleasant, or more instructive, than to compare experience with expectation, or to register from time to time the difference between idea and reality. It is by this kind of observation that we grow daily less liable to be disappointed.”
—Samuel Johnson (1709–1784)
“I should say that the most prominent scientific men of our country, and perhaps of this age, are either serving the arts and not pure science, or are performing faithful but quite subordinate labors in particular departments. They make no steady and systematic approaches to the central fact.... There is wanting constant and accurate observation with enough of theory to direct and discipline it. But, above all, there is wanting genius.”
—Henry David Thoreau (1817–1862)