The Dial of Ahaz

December 2017 marks the tenth anniversary of Christopher Daniel's article in Clocks Magazine about the Dial of Ahaz. Much has been written about the ‘Dial of Ahaz’ which is referred to in the Bible, in the Old Testament at 2 Kings and in Isaiah, as to what kind of sundial it might have been and how it would have worked, some with ingenious but inconclusive theories. There is also a discussion on this matter in the British Sundial Society Bulletin by John Wall: "The Dial of Ahaz". BSS Bulletin 19(iii) 141-144.

Christopher's article itself is at the left - though a better quality PDF version may be opened by clicking on the image here. [Both reproduced here with permission].

Some interesting additional comments about the phenomenon described in the Bible were published in the Spectator in February 2010 and in The Traveller in 2007.  See what others have said and whether or not you agree with the views expressed. The problem is that no one even knows what type of dial it was and perhaps worse, the Jews living at the time didn't measure time like we do today!
Spectator 19 FEBRUARY 1910, Page 19
SIR, May I make a suggestion with reference to the following words contained in a review paragraph in last week's Spectator on the " Temple Bible Dictionary It is certainly clear that if it is literally true that Isaiah made the sun to retreat," &c. The prophet Isaiah is recorded (Isaiah xxxviii. 8 and 2 Kings xx. 11) as being permitted to give Hezekiah a sign from the Lord that he should recover, the sign being that " the shadow of the degrees on the dial of King Ahaz went backward ten degrees." What may have taken place is what I have myself actually seen occur with the shadow of the tall trunk of a young oak-tree thrown upon the side of a barn,—a shadow by which I had so often measured the approximate time that. I used to call the barn and the oak-tree " the dial of King Ahaz." On one day an unusually heavy stationary mass of storm-cloud obscured the sun itself, but the sunlight, blazing through a rift in the cloud to one side of the sun, cast the shadow of the oak's trunk back to a point a quarter of the circle from where it had just been. If the " dial of Ahaz " was a pillar or obelisk, the shadow of which was thrown upon a circle of degrees marked on the ground or on a wall, the same thing could have occurred without any convulsion of the solar system.—I am, Sir, &c.,


Don Stewart: Did God Backup the Sun Dial for Hezekiah?

During the reign of King Hezekiah, he asked for a confirmatory sign from the prophet Isaiah to verify that all Isaiah had predicted was true. We have the following account:

And Hezekiah said to Isaiah, What is the sign that the Lord will heal me, and that I shall go up to the house of the Lord the third day? Then Isaiah said, This is the sign to you from the Lord, that the Lord will do the thing which He has spoken: shall the shadow go forward ten degrees or go backward ten degrees? And Hezekiah answered, It is an easy thing for the shadow to go down ten degrees, no but let the shadow go backward ten degrees. So Isaiah the prophet cried out to the Lord, and He brought the shadow ten degrees backward, by which it had gone down on the sundial of Ahaz (2 Kings 20:8-11).

And this is the sign to you from the Lord, that the Lord will do this thing which He has spoken: Behold, I will bring the shadow on the sundial, which has gone down with the sun on the sundial of Ahaz, ten degrees backward. So the sun returned ten degrees on the dial by which it had gone down (Isaiah 38:7,8).

Hezekiah was offered a choice: the shadow on the sundial could go either 10 degrees backwards or forwards. Hezekiah assumed that the sun going backward would be a greater sign since it would go against nature. God granted Isaiah's prayer and the 'sign' occurred.

Stewart, D. (24 Apr, 2007). Did God Backup the Sun Dial for Hezekiah?

How did God move the sundial? Part of our consideration of this 'miracle' concerns the type of sundial that was in mind. There have been three different suggestions:
1. The sundial was possibly a series of steps leading from east to west. As the sun sank in the west the shadow would come down the steps and a glance at this shadow on the steps would indicate how much daytime was left.
2. Another type suggested is a hollowed out hemisphere with lines on the inside wherein the shaded part will intersect various lines and show the time of day.

3. A third suggestion is that the sundial was a pillar with steps around it and as the sun moved across the heavens, the shadow of the pillar would fall on different steps, thus, giving a rough estimate of the time of day.

Regardless which of the three sundials were used the ''miracle'' would be obvious to all concerned. It would not be as miraculous for the shadow to advance ten degrees as for the shadow to retreat. Only supernatural intervention could cause the latter. This is the 'miracle' that Hezekiah received. If the 'miracle' occurred, how and what happened?

- Sun Backed Up?
One possibility is that the earth backed up in its trajectory to shed more daylight upon the sundial. The problem with this view is that it disturbs all the machinery in the heavens. There would have been untold destruction if this happened unless God supernaturally intervened. While this is possible, it is not necessary to assume that this is what occurred. In addition, 2 Chronicles 32:31 seems to restrict the phenomenon to the land of Palestine:

However, regarding the ambassadors of the princes of Babylon, whom they sent to inquire about the wonder that was done in the land, God withdrew from him, in order to test him, that He might know all that was in his heart (2 Chronicles 32:31).

If this be the case, then it is not necessary to say that the sun backed up its trajectory.

- Mirage
Others have thought that the 'miracle' was a supernatural mirage of the sun:

The theory of Butler is that the 'miracle' was a supernatural superior mirage of the sun. Lateral images have been known to shift objects ninety degrees. Butler tells of Martin, one of the round-the-world fliers of 1924, who crashed his plane in Alaska because a lateral image moved a mountain ninety degrees out of its place! So, Butler reasons, a superior image of ten degrees would be no great phenomenon

- Lighting Up The Steps
The 'miracle' was more likely that of lighting up the steps. This is a result of the direct intervention of God. W.F. Arndt comments:

The writer does not say that this was due to the movement of the sun. He furnishes no explanation. His account makes it possible to assume that the 'miracle' was confined to what happened on the sundial . . . The prominence which is given to the dial and the shadow strongly supports this view. Since there is no mention of the lengthening of the day, this seems preferable to the view that understands Isaiah to say that the sun reversed its course and shone ten hours or so longer than usually.

Then there is Voltaire's comment (here in English):

Or finally, maybe this from Jonathan Bayley: The Divine Wisdom of the Word of God (1892) !

[Back to SunInfo]