John Calvin's reputation has suffered tremulously due to the following quotation that was wrongly attributed to him by famous men such as Bertrand Russell, Thomas Kuhn and many others, which Calvin had never uttered:

"Who,' asks Calvin, 'will venture to place the authority of Copernicus above that of the Holy Spirit?", Pseudo-John Calvin.

There remains a debate whether John Calvin ever read or heard of Nicolaus Copernicus at all, however, this is unlikely because we know that his dialog partners and disciples, most notably Theodore Beza, had read Copernicus' theories.

Richard Stauffer recent publications has resulted in a changed consensus that acknowledges that John Calvin never directly condemned Copernicus as a heretic as previously thought, however it has become clear due to Stauffer's work, most notably his discovery of a quotation John Calvin's sermon on 1 Corinthians 10-11, that Calvin did condemn the Heliocentric theory, and that Calvin likely had some awareness of Copernicus's work revealed in the following Calvin quotation:

[The Christian is not to compromise so as to obscure the distinction between good and evil, and is to avoid the errors of] "those dreamers who have a spirit of bitterness and contradiction, who reprove everything and prevent the order of nature. We will see some who are so deranged, not only in religion but who in all things reveal their monstrous nature, that they will say that the sun does not move, and that it is the earth which shifts and turns. When we see such minds we must indeed confess that the devil posses them, and that God sets them before us as mirrors, in order to keep us in his fear. So it is with all who argue out of pure malice, and who happily make a show of their imprudence. When they are told: "That is hot," they will reply: "No, it is plainly cold." When they are shown an object that is black, they will say that it is white, or vice versa. Just like the man who said that snow is black; for although it is perceived and known by all to be white, yet he clearly wished to contradict the fact. And so it is that they are madmen who would try to change the natural order, and even to dazzle eyes and benumb their senses." John Calvin, "Sermon on 1 Corinthians 10:19-24", Calvini Opera Selecta, Corpus Refomatorum, Vol 49, 677, trans. by Robert White in "Calvin and Copernicus: the Problem Reconsidered", Calvin Theological Journal 15 (1980), p233-243, at 236-237

I found the above quotation first referenced by R.C. Sproul, and then referenced by Keith Matthison, and then several academic articles on Calvin, and lastly in a very helpful article that summarizes Calvin on Copernicus in an article by Keith C. Sewell, "Calvin and the Stars: Kuyper and Fossils: Some Historiographical Reflections" [mirror].

The following two quotes represent two conservative Reformed voices that affirm that John Calvin (as well as Martin Luther) had condemned Copernicus's Theory:

"But historically the Church's understanding of special revelation of the bible has been corrected by students of natural revelation with the Copernican Revolution. Both Calvin and Luther rejected Copernicus as an Heretic in the sixteenth century. I don't know anybody in Orthodox Christianity today who is pleading for Geocentricity. Do you? Do you know anybody? In that case, the church is saying we misinterpreted the teaching of the bible with respect to the solar system, so thank you scientists for correcting our misunderstanding. So I think we may learn from non-believing scientists, whom are studying Natural Revelation, they may be getting a better sense of the truth by studying the Natural Revelation, from what I get for ignoring Natural Revelation. I have a high view of Natural Revelation, is what I'm saying. However, if something may be shown that is definitively be taught in the bible, without question, and someone gives me something that is from Natural Revelation, that they think is from Natural Revelation, I'm going to stand with the Word of God a hundred times out of a hundred, but I may be a mistaken interpreter. I don't have to face that problem, because I believe both spheres are god's spheres of revelation." R.C. Sproul, Science, Scripture, and the Age of the Universe from Ligonier Ministries on Vimeo.

And also Keith Mathison's book:

"However, even though Calvin did not make the oft-quoted statement about Copernicus cited above, a statement he made in a sermon on 1 Corinthians is relevant. There, Calvin warns against those who say “that the sun does not move and that it is the earth that moves.” He describes those who hold this view as “stark raving mad” and as “possessed” by the Devil. It is not clear that he is basing this warning on his interpretation of any particular passage of Scripture, and there is ongoing debate about how this statement coincides with Calvin’s other statements regarding general and special revelation, but at the very least, the statement does indicate that geocentricity was firmly established in Calvin’s mind as the true explanation of the nature of God’s creation." Mathison, Keith (2013-12-03). A Reformed Approach to Science and Scripture (Kindle Locations 358-364), Kindle Edition.

Consistently cited as a proof of Calvin's Geocentricity is his Commentary on Psalm 93:1:

"A simple survey of the world should of itself suffice to attest a Divine Providence. The heavens revolve daily, and, immense as is their fabric, and inconceivable the rapidity of their revolutions, we experience no concussion — no disturbance in the harmony of their motion. The sun, though varying its course every diurnal revolution, returns annually to the same point. The planets, in all their wanderings, maintain their respective positions. How could the earth hang suspended in the air were it not upheld by God’s hand? By what means could it maintain itself unmoved, while the heavens above are in constant rapid motion, did not its Divine Maker fix and establish it? Accordingly the particle אף, aph, denoting emphasis, is introduced — Yea, he hath established it." John Calvin, "Commentary on the Psalms: Volume IV", Ps 93:1

Calvin's Commentary on the Psalms was published after his definitive 1559 Latin Edition of the Institutes of the Christian Religion, establishing that this was his developed cosmological understanding of the world, and a statement many year after his colleagues were already aware of Copernicus' relevant works. The conclusion is that Calvin was opposed to the Heliocentrical model and firmly seated in the Geocentric model of his day. However, Calvin has certainly not laid down the ultimatum of the pseudo-Calvin quote that demands us choose between the Word of God and Copernicus. It is quite natural and appropriate to understand Calvin as accepting the prevailing cosmology of his day, rather than chasing (from his perspective in history), a novelty that is against the scientific consensus of the experts of his era.

At this point an excursus on Calvin's Doctrine of Accommodation is most helpful. Calvin did not believe that the bible reveals scientific data, but rather it reveals the Word of God in a way that it may be understood by the bible's readers, and accommodates the revealed Word of God to the common understanding of the hearer of the Word, even if that means communicating the Word of God through the flawed hearer's historical, scientific, theological, and cosmological errors. The following quotations from Calvin's Commentary on Genesis: Vol 1 serve as examples of Calvin's "Accommodation":

I do not doubt that the most ancient fathers, to whom the coming night was the end of one day and the beginning of another, followed this mode of reckoning. Although Moses did not intend here to prescribe a rule which it would be criminal to violate; yet (as we have now said) he accommodated his discourse to the received custom. Wherefore, as the Jews foolishly condemn all the reckonings of other people, as if God had sanctioned this alone; so again are they equally foolish who contend that this modest reckoning, which Moses approves, is preposterous. The first day Here the error of those is manifestly refuted, who maintain that the world was made in a moment. For it is too violent a cavil to contend that Moses distributes the work which God perfected at once into six days, for the mere purpose of conveying instruction. Let us rather conclude that God himself took the space of six days, for the purpose of accommodating his works to the capacity of men. John Calvin, Commentary on Genesis: Vol 1, Genesis 1:5 16. The greater light I have said, that Moses does not here subtilely descant, as a philosopher, on the secrets of nature, as may be seen in these words. First, he assigns a place in the expanse of heaven to the planets and stars; but astronomers make a distinction of spheres, and, at the same time, teach that the fixed stars have their proper place in the firmament. Moses makes two great luminaries; but astronomers prove, by conclusive reasons that the star of Saturn, which on account of its great distance, appears the least of all, is greater than the moon. Here lies the difference; Moses wrote in a popular style things which without instruction, all ordinary persons, endued with common sense, are able to understand; but astronomers investigate with great labor whatever the sagacity of the human mind can comprehend. Nevertheless, this study is not to be reprobated, nor this science to be condemned, because some frantic persons are wont boldly to reject whatever is unknown to them. For astronomy is not only pleasant, but also very useful to be known: it cannot be denied that this art unfolds the admirable wisdom of God. Wherefore, as ingenious men are to be honored who have expended useful labor on this subject, so they who have leisure and capacity ought not to neglect this kind of exercise. Nor did Moses truly wish to withdraw us from this pursuit in omitting such things as are peculiar to the art; but because he was ordained a teacher as well of the unlearned and rude as of the learned, he could not otherwise fulfill his office than by descending to this grosser method of instruction. Had he spoken of things generally unknown, the uneducated might have pleaded in excuse that such subjects were beyond their capacity. Lastly since the Spirit of God here opens a common school for all, it is not surprising that he should chiefly choose those subjects which would be intelligible to all. If the astronomer inquires respecting the actual dimensions of the stars, he will find the moon to be less than Saturn; but this is something abstruse, for to the sight it appears differently. Moses, therefore, rather adapts his discourse to common usage. For since the Lord stretches forth, as it were, his hand to us in causing us to enjoy the brightness of the sun and moon, how great would be our ingratitude were we to close our eyes against our own experience? There is therefore no reason why janglers should deride the unskilfulness of Moses in making the moon the second luminary; for he does not call us up into heaven, he only proposes things which lie open before our eyes. Let the astronomers possess their more exalted knowledge; but, in the meantime, they who perceive by the moon the splendor of night, are convicted by its use of perverse ingratitude unless they acknowledge the beneficence of God. John Calvin, Commentary on Genesis: Vol 1, Genesis 1:16

Sewell's article summarizes the data well when he writes:

"As for John Calvin, he took great pains to distinguish between astrology and astronomy. While he supported the later, he wrote against astrology [..]. Moreover, in his entire approach, Calvin seems to have been less inclined towards biblicism. Consider, for example, these statements drawn from his discussion of Psalm 136: "Moses calls the sun and moon the two great lights, and there is little doubt that the Psalmist here borrows the same phraseology. What is immediately added about the stars, is, as it were, accessory to the others. It is true, that the other planets are larger than the moon, but it is stated as second in order on account of its visible effects. The Holy Spirit had no intention to teach astronomy; and, in proposing instruction meant to be common to the simplest and most uneducated persons, he made use by Moses and the other Prophets of popular language, that non might shelter himself under the pretext of obscurity, as we will see men sometimes very readily pretend an incapacity to understand, when anything deep or recondite is submitted to their notice. Accordingly, as Saturn though bigger than the moon is not so to the eye owing to its greater distance, the Holy Spirit would rather speak childishly than unintelligibly to the humble and unlearned." Here is an important statement about both the perspicacity and intentions of the Holy Scripture. It fully respects the divine inspiration and authority of the Scripture, and in principle it sets aside any need for the kind of literalism that the twentieth center would associate with fundamentalism. Here is a view of the scriptures that has no need to panic before the latest theories of a Copernicus, Kepler, or Galileo. Calvin may well be best understood as pre-Copernican rather than anti-Copernican or pro-Copernican. Nevertheless, even if on occasions he was inclined to be anti-[Copernican], his view of biblical hermeneutics was such that it did not dogmatically preclude the acceptance of heliocentricity." Keith C. Sewell, "Calvin and the Stars: Kuyper and Fossils: Some Historiographical Reflections" [mirror], pg15-16

In conclusion, it would be a great error to use John Calvin's 16th century mind to oppose the accepted scientific consensus of today. He was not literal biblicist or fundamentalist that opposed Scientific Knowledge or one to vet the Word of God against the world which is the Theatre of God's Glory. Incarnationally, it would be appropriate to believe that if John Calvin lived today, over 500yrs after his birth, that he would not support the scientific conspiracies of factional groups, in the same way that he did not accept Copernicus, but we would think of him as embracing the Science of our day. If anything Calvin's rejection of Copernicus teaches us to be cautious in rejecting such conspiracies against the established scientific theories of today. Lastly, Calvin's error in rejecting Copernicus reveals that even the greatest Church Father's were not protected by the Bible from committing grave scientific errors. We must then conclude to have extreme caution in ever opposing science with biblical data, when so many great Church Fathers, including our precious John Calvin, Martin Luther and all the Reformed Fathers of the Faith, as well as the Catholic Fathers of the past have had significant errors as well.