1979 Lowitz Arcs

1979 Lowitz Arcs

Ted Madden saw this halo display over southern Utah in January 1979. �Would've missed this if we hadn't stopped to change drivers.� He was lucky indeed. This image is possibly the first ever reported that shows the enigmatic Lowitz arcs.

OPOD routinely searches any images sent in for Lowitz arcs. They are fairly obvious on this one even before any enhancement. There is an upper Lowitz curving outwards from the 22� halo at 2 and 10 o�clock to meet the bright Parry arc at top. The 22� halo has characteristic 'Lowitz gaps' near the sundogs and there are hints of arcs towards the parhelia.

Tobias Lowitz drew his arcs during a halo display over St. Petersburg, Russia in 1790. Since then there has been much controversy over their their very existence. Searchers looked near sundogs where Lowitz drew them. However, they are usually quite indistinct there. They are much better seen, as here, curving upwards to the Parry arc.

Despite many searches they were not photographed until 2-3 decades ago. Robert Gorkin�s 1988 images** and that of Petri Hakkarainen*** in 1994 are prime examples.

Now the time line pushes back to 1979.

Do dusty cupboards hold yet earlier images?

Image ©Ted Madden, shown with permission

A HaloSim ray tracing.

Lowitz arcs are in red and for clarity are shown at a higher crystal concentration.

Thick and regular hexagonal plates were used taking all orientations about the Lowitz axis AA.

The middle arc is faint and elusive near the parhelia.

Enhancement by colour subtraction, levels adjustment, noise reduction and slight embossing in Photoshop.

There are hints, but only hints, of Lowitz arcs curving up and down from the parhelia to meet the 22° halo.

At left there is 'possibly' a middle Lowitz.

The upper Lowitz is clear.

** Greenler, R., Cowley, L and Gorkin, R., Invited lecture, Light & Color 2013
Conference, Fairbanks, Alaska.

*** Riikonen, M., Cowley, L., Schroeder, M., Pekkola, M, Öhman, T. and Hinz, C.,
The Lowitz Arcs, Weather, September 2007, Vol.62, No.9, pp252-6