Thursday, 21 September 2017

Halos on the night of 14/15 December 2016 in Rovaniemi, part II

Here is a collection of images showing an arc that looks like a downwards curving Hastings or Wegener. It's nothing new: the arc was first observed in Rovaniemi on 23 November 2015 and again nine days later in the evening of 2 December. I don't know how it is made, but it seems to occur when the display is suboptimal as compared to its best development. A halo that thrives on (relatively) crappy crystals?

In the display on the evening of 14 December 2016 this anomalous Hastgener was captured on several stacks, one of which is shown above and which also has normal Hastgener. Below are two more photos of which at least the left side one shows the effect. It was true to form, as these stages did not represent the peak of the display.

There was an additional oddity: the Hastgener / anomalous Hastgener has a kind of parhelia near the tangent arc. The feature occurred intermittently and was well visible to the eye. Below are two images showing this "parhelia", the one on the left is a single frame. The brightening seems to be also present in the main image above.


  1. I'm intrigued by this notion of poor quality crystals producing monster hybrid split personality halos. I think they deserve a name all to themselves, possibly even a humorous one. I suppose we are all used to poor quality halos or display, but only in Finland could such sub-optimal crystals produce such an exotic creature!

  2. Hastings and Wegener are horizontal arcs on the sun side of the sky. The anomalous Hastgener is not horizontal arc, it is curving downwards. I have not been able to simulate it nor the brightening.

    Let them name suggestions come. Concerning my previous post on this display, Michael came up what I think was a pretty decent name idea for the new halo there. And Alec may be on the right track here. They recently named some newly found aurora effect "Steve". Should we follow in similar off the cuff spirit? Especially for the wierdest stuff.

    By the way, notice in the left side br image of the upper pair the red segment inside the blue circle. I think I have this also in another display. I have not seen such effect in simulations.

  3. I haven't read the Jekyll & Hyde story, but these words appear to be also a term "used in reference to a person or thing that alternately displays two different sides to their character or nature". Now the anomalous Hastgener is a rather stable fellow - it seem to have pretty much same the downwards curving form in all the displays. But possibly this still could be as good a name as any other. What I like is that there is no "arc". We all know they are arcs anyway, so the "arc" might as well be disposed of when naming some new stuff.