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  Rays & Shadows
  Water Droplets
    Clouds & Fog
    Droplets & Light
    Iridescent Clouds
    The Glory
    IRIS software
       How it works
       Known issues
  Ice Halos
  High Atmosphere
  Links & Resources
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   Download IRIS Latest version is 2.1.2 

    IRIS may be freely downloaded.   It must not be redistributed on web sites or CDROMs or by other means or resold. Commercial copying or sale is forbidden. If you publish simulations please acknowledge the use of IRIS and quote in the caption the URL atoptics.co.uk     ©2002 Les Cowley.  All rights reserved.

  IRIS runs on PCs with Windows95 or higher.   It needs a 24bit colour display. Disk memory use is small.
   If HaloSim is NOT already installed:

(1)  Download 'iris2.zip'  here
(2)  EXTRACT into a temporary folder
(3)  RUN 'setup.exe'. When prompted chose a folder for the program or use the suggested default.
(4)  RUN 'Iris.exe'

 If HaloSim or an earlier version of IRIS is already installed.   On many PCs
 with HaloSim already present it will only be necessary to download a much
smaller file. If this does not work, download 'iris2.zip' and follow the
 instructions above.

(1)  Download the smaller 'irisup2.zip' file  here
(2)  EXTRACT into a new folder
(3)  RUN 'Iris.exe'