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In a Swedish church record from 1689 a phenomenon in the sky is described. With my very limited understanding it could be a meteorological or an astronomical phenomenon, so here I ask if it could have have an astronomical phenomenon, and what it was in that case.

The place

The observations were made from the village of Fagerhult in Kalmar län in Sweden, at 57°08′55″N 15°39′52″E, in the sky to the North-East.

The time

This was 18 December 1689 (according to the Gregorian calendar – actual date given in the document is Julian 8 December).

It was "around 4 in the afternoon, around sunset". (I think that sunset actually was at about 3:15 PM local time.)

Description

It is described as an elongated cross with the long arm being about 6 times as long as the short arm. I think it means to say that the long arm was vertical, but I'm not sure about that. The cross was shining clearly on the sky, a burning light in the north-east for about an hour. It was almost a clear sky and where the cross was there were no clouds at all.

The account is accompanied by this illustration. It doesn't have the same proportions as I understand the text to say. Maybe the image is better than the text. enter image description here


(Undoubtely this led to religious ponderings, and that was presumably why this was recorded, but there is actually nothing of that in the note – just this description.)

Was there anything special happening in the sky then that could have to do with this?

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    $\begingroup$ So the "Great Comet of 1680" could have a role in this? $\endgroup$ – pst Jul 30 at 20:08
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    $\begingroup$ Hypothetically, yes. From the description this could have been a zodiacal light. They are caused by scattering of sunlight in interplanetary dust. A sungrazing comet had passed a decade back, then. It might have been destroyed, leaving a cloud and trail of dust behind orbiting the sun. A few years later the earth may have passed in such a manner that remnants of the trail were in a perfect position between it and the sun for a cool show, because skies were much darker than. I know, it is a long way and not good enough for a concise answer, but it would explain the description. $\endgroup$ – a_donda Jul 30 at 22:02
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    $\begingroup$ A question on translation - given the appearance of the sketch, is it possible that what you translate as "long" is actually "wide"? That is, that the wide part was 6 times as wide as the narrow part? This may be unlikely, but I don't know what the words are in Swedish, and that would be more consistent with the drawing. $\endgroup$ – ELNJ Jul 30 at 23:54
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    $\begingroup$ This was almost certainly more "Earth Science" than "Astronomy". $\endgroup$ – Mark Jul 31 at 2:32
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    $\begingroup$ @ELNJ I don't think that's possible. It talks about how "långt" the parts are, which is length. Maybe I should have said that it never says "6 times" though, but that was my derivation. What it actually says is that the trunk was like "3 fathoms" and the other part "1½ ell" where a Swedish fathom (famn) was 3 ell (aln). $\endgroup$ – pst Jul 31 at 8:11
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This is a really interesting question! One thing to note is that since it appeared in the northeast at sunset, it is nowhere near the sun - in fact, it is pretty much in the opposite direction as the setting sun. In the winter in the north, the sun would set in the southwest. And regarding your comment about the text describing the event as "around sunset" when it would have been 45 minutes later, I think that's not surprising - at northern latitudes in the winter, around the winter solstice, the path of the sun is at a very oblique angle to the horizon, so twilight lasts quite a long time. So it could easily feel like "sunset" for an hour or more. Though the sun set at 3:15 PM as you note, at 4:00 PM the sun would still only be 5.3 degrees below the horizon, so civil twilight had not yet ended. Plus, no one in those days was wearing a wristwatch, so a given observer's estimate of time of a particular event may have been less precise than we would be accustomed to now.

So, my best guess is that this might have been related to anticrepuscular rays. Pros and cons for this hypothesis:

Pros:

  • Appears at the right time of day, in the right location (opposite the setting sun).
  • Would give a vertical ray.
  • Doesn't need clouds in the direction that the image is seen. (But see my comment below about the crossbar.)

Cons:

  • Most of the cases I can find pictured have multiple rays, which isn't what is described here.
  • There is no obvious explanation for the horizontal part of the cross.
  • I'm not sure if this would persist without obvious changes for as long as described.

Another thought I had, which looks very similar in appearance, but is in completely the wrong direction, is a sun pillar, combined with a stratus cloud, like this (from here):

Sun pillar plus clouds

The appearance is striking, but (a) it would have to be in the sunset direction, and (b) there would have to be clouds. So it doesn't seem to quite work.

I also thought of the moon, and whether that could give something similar, e.g. if it was just below the horizon. But that doesn't quite work, either. I did some calculations, and the moon was 38% full that day (waxing crescent, one day short of first quarter). At 4:00 PM (assuming that the location is UTC+1 hour), the moon would have been 23 degrees above the horizon, at an azimuth of 161 degrees, i.e. low in the south-southeast. So that doesn't seem like it would contribute much to something in the northeast.

So clearly I don't have a definitive answer, but maybe something here will be helpful or give others some ideas.

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    $\begingroup$ "In the winter in the north, the sun would set in the southeast." ← I think you meant to write southwest. $\endgroup$ – Will Jul 31 at 11:56
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    $\begingroup$ Of course you’re right, thanks! I’ll edit it right now. $\endgroup$ – ELNJ Jul 31 at 11:58
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    $\begingroup$ Hmm, though, the principle does work, we can never be sure if such overly perfect images aren't made up. It's a few clicks with an image manipulation program ... $\endgroup$ – a_donda Jul 31 at 12:07
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    $\begingroup$ @a_donda sure it's good to be critical about sources. Yet the variety of sources showing images like this from different locations, different observers, and often in a photographic and scientific context lends quite a bit creditiblity to an interpretation like shown here in this answer and my answer. Having seen and imaged a few halo phenomena myself, it's very easy to believe that this image is not edited or fake $\endgroup$ – planetmaker Jul 31 at 12:41
  • $\begingroup$ The image of the "sun pillar" looks stunning, but I don't think they would have been so mistaken about the direction, so I don't think this add-on is right and it's the main thought about something related to anticrepuscular rays that counts. I have upvoted both answers, but have no clue if this or the one about some kind of halo effect is "better" so that's why I haven't accepted any answer (yet). $\endgroup$ – pst Aug 1 at 10:25
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That is hard tell; from your description it reads like a spectacular halo phenomenon.

They are more common when the sun is still up in the sky, but even after sunset many are possible and they can combine. With the right atmospheric conditions they can be very impressive experiences.

See for instance this somewhat cross-shaped halo at sunset. Two of the most common phenomena are the light pillar which is especially impressive near dusk and dawn and several circular halos - which can combine to a cross-shape when near horizon. Add in sun dogs which add bright spots 60° or even 120° from the sun's current position, this might explain bright(er) light in the North-East. Here is a schematic overview (German) over many halo types

See also this wikipedia article which reports a painting of a particular impressive scene which was interpreted as sign of heavens. Combinations with sun pillars also give cross - like sights in the right circumstances, e. g. https://www.pinterest.de/pin/757871443529277426/ or here http://old.meteoros.de/arten/ee08e.htm

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    $\begingroup$ For the first image: According to the description, it was Sunset $\endgroup$ – Jonas Jul 30 at 15:46
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    $\begingroup$ thanks indeed. removed the ? about sunrise $\endgroup$ – planetmaker Jul 30 at 15:48
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    $\begingroup$ Looks impressive, but maybe not fitting because of the missing center? (I've added an image of the cross to the question now.) $\endgroup$ – pst Jul 30 at 20:16
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    $\begingroup$ Halo are so variabel... I added links to two further images $\endgroup$ – planetmaker Jul 30 at 22:28

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