Showing posts with label column oriented crystals. Show all posts
Showing posts with label column oriented crystals. Show all posts

Wednesday, 24 February 2016

Diamond dust halos on the night of 12/13 January, part I



With this post starts the presentation of January 12/13 night results in Rovaniemi. All photos are in spotlight beam. The image above is a singe frame with 30s exposure. Just basic halos there. In the rest of the images emphasis is on the crystal glitter formation that makes an intensity threshold at the zenith. The ray-path for this effect, which is quite common in spotlight displays, is 3-5-7 and here it is from column oriented crystals. What’s peculiar is the psychedelic colours of individual crystals, as shown by the left side image below that is a maximum stack of four frames. In the 20 frame average stack next to it the colours are washed away. The lamp is the usual 5 degrees below horizon. In the images below are two single frames which display the coloured glitter even more clearly and another maximum stack of 14 frames. Individual frames are all 30s exposures.


Marko Riikonen







Wednesday, 3 May 2006

Ice Crystals






















"Atmospheric Optics" has a newly updated section about halo forming ice crystals - check under "What's New". Plate, column and pyramidal crystals are illustrated with their orientations and resulting halos.