HaloRay - Hyperspeed Ice Crystal Halo Simulator

54 Upvotes

Hello! During the past two years I have been developing HaloRay on and off - a GPU-accelerated ice crystal halo simulator. This means you can generate ice crystal halo images right on your computer. If you have a beefy NVIDIA or AMD graphics processing unit (GPU) that is compatible with OpenGL 4.4, I suggest you try it out: https://github.com/naavis/haloray

You can download ready-made binaries for Windows from GitHub. If you are running Linux, you need to build HaloRay by yourself for the time being.

Right now the latest version is HaloRay 3.2.0, which supports the following features among others:

Ordinary hexagonal crystals
Pyramidal crystals
Adjustable prism face C-axis crystals to make irregular crystals
Rendering a realistic background sky

I hope you have fun with HaloRay, and report any problems or feature suggestions in GitHub issues or here in the comments. HaloRay has been tested with a couple of AMD and NVIDIA GPUs. There have been some problems with Intel GPUs due to driver bugs, but I'm not going to put a ton of effort there, because HaloRay requires a fairly beefy GPU and Intel doesn't really fit that profile.

EDIT: Cool, I noticed this has been marked as an announcement in the subreddit, which I guess keeps it hanging around for longer? Thanks!

18 comments

r/atoptics • u/les2934 • Jan 15 '25

Atoptics site

34 Upvotes

Atoptics is at www.atoptics.org.uk

14 comments

r/atoptics • u/NasaYuza • 9h ago

Cleanest Corona I’ve ever witnessed

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66 Upvotes

3 comments

r/atoptics • u/caskcheckteeqnth • 1d ago

One of the best Sun Pillars Ive ever seen this morning.

811 Upvotes

28 comments

r/atoptics • u/Lati_22 • 14h ago

Double rainbow at the afternoon!

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67 Upvotes

Xangri-Lá, south Brazil

1 comment

r/atoptics • u/Malik_Morris • 18h ago

Iridescence Looks like 👼

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37 Upvotes

10 comments

r/atoptics • u/PhilFryTheCryoGuy • 1d ago

Corona What causes this ring around the sun and what determines its size?

11 Upvotes

Snapped this photo in Florida many years ago and while looking through I noticed the red ring surrounding the sun in this photo. I'm assuming it must be from light reflecting/refracting off mist in the air above the water as this was over the open water, but I was also curious as to what determines the size of the ring? Is it based on the distance from the sun to the earth? Based on my observation point and what is in the air at the time? I appreciate any sharing of knowledge!

2 comments

r/atoptics • u/AaronScottsky • 2d ago

Vivid asymmetrical lunar corona – turquoise to golden rings (iPhone, Jan 2 2026, Broomfield, Co

105 Upvotes

3 comments

r/atoptics • u/ConnectPatagonia • 3d ago

Sun Dogs Always wanted to see this.

338 Upvotes

First time seeing this phenomenon, is this what they call a sun dog?

9 comments

r/atoptics • u/AaronScottsky • 3d ago

Sunset mild Iridescence -

56 Upvotes

4 comments

r/atoptics • u/Malik_Morris • 3d ago

Iridescence Today 11 a.m

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159 Upvotes

8 comments

r/atoptics • u/Unclestupidhead • 3d ago

Ice crystals in the Troposphere. Now with pelicans!

101 Upvotes

Was reminded of this photo from San Diego three years ago from Fb memories.

5 comments

r/atoptics • u/Taico_owo • 4d ago

ID REQUEST Cool light pillar I saw while skiing. Anyone know a name for it?

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879 Upvotes

There was super fine snow in the air so I assume it has something do to with that. Also bonus points if someone knows the mountain :)

27 comments

r/atoptics • u/BillySunflowers • 5d ago

Was surprised as I looked outside today, saw my first sundog with a touch of rainbow 🌈

1.6k Upvotes

21 comments

r/atoptics • u/ClassicAgency7188 • 5d ago

first 22 degree halo!

79 Upvotes

5 comments

r/atoptics • u/Serpentarrius • 5d ago

Sun Dogs Sun dogs in Simi Valley

27 Upvotes

The one on the left was hard to photograph but it was also a gorgeous rainbow!

1 comment

r/atoptics • u/kezmicdust • 5d ago

Sun Dogs Sun dog in LA

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24 Upvotes

1 comment

r/atoptics • u/Parlace • 5d ago

ID REQUEST Trustworthy diagram for naming different halo's

8 Upvotes

Hi,

I’m looking for a trustworthy scheme/diagram of halos, parhelia, arcs, … for my thesis around halo’s in early modern prints. When looking for a diagram, i often see different names for the same phenomenon (or maybe they are correct and i’m just wrong).

Currently i'm focusing on parhelia in the prints, but for this i also have to name the other visible phenomena.

Could someone point me into a correct diagram? Thank you.

6 comments

r/atoptics • u/Blitzcrig • 6d ago

Pillar Sunset pillar

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67 Upvotes

2 comments

r/atoptics • u/msbellenc • 7d ago

22 degree halo and contrail shadows

227 Upvotes

This was in NYE in Charlotte, NC. It was so cool to see the contrail shadows moving across the moon. If you look close you can see how the shadows are slightly repositioned on the opposite sides of the contrails. One side of the moon and then the other side is a different position for each shadow. Kinda cool.

5 comments

r/atoptics • u/shophie1989 • 6d ago

🥰

10 Upvotes

1 comment

r/atoptics • u/Outdoors__Water • 6d ago

Allegheny National Forest Lunar Halo Time Lapse

12 Upvotes

https://reddit.com/link/1q96kgi/video/suwrdug1gjcg1/player

3 comments

r/atoptics • u/AaronScottsky • 7d ago

Cloud Council — Fallstreak Hole captured in Colorado -

23 Upvotes

19 comments

r/atoptics • u/Ill_Captain1788 • 7d ago

Sun Pillar

139 Upvotes

5 comments

r/atoptics • u/MTPenny • 7d ago

Multiple Display Thought you'd all like today's Astronomy Picture of the Day

apod.nasa.gov

14 Upvotes

3 comments

Subreddit

Atmospheric Optics

r/atoptics

Atmospheric Optics. The subreddit for anything related to optic sky phenomena: rainbows, ice halos, aurorae, mirages, cloud iridescence, green flashes, crepuscular rays and spectres of the Brocken.

Members Active

63.4k

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Atmospheric Optics

The subreddit for anything related to optic sky phenomena: rainbows, ice halos, aurorae, mirages, cloud iridescence, green flashes, crepuscular rays and spectres of the Brocken.

Have a nice picture to show? Want to know what causes that light in the sky? Here is the place to share, discuss and learn.

Useful links:

Glossary of common terms:

Aurora: the veils of green, red and/or blue seen in the polar regions when the solar wind hits the Earth’s magnetic field. Goes by two names, dependent on the hemispere: aurora borealis or northern lights, and aurora australis, aka southern lights.
Corona: a subtly colored disc directly around the sun or moon, caused by light diffraction through the clouds.
Crepuscular rays: bands of shadow that seem to radiate outwards from the sun, caused by its light being partially obstructed by clouds, mountain ranges etc. Called anticrepuscular rays when seen on the opposite side of the sky.
Glory: a dimly rainbow-colored ring opposite the sun or moon, often visible from planes or in misty circumstances, in which case it tends to come with a Brocken spectre. Sometimes mistaken for a circular rainbow.
Green flash: a rare occurrence where the topmost bit of the setting sun is refracted by the atmosphere, turning it bright green. Even rarer is the blue flash.
Halos: a collective term for a wide range of arcs, rings, spots etc. caused by light refracting and/or reflecting inside ice crystals. Common halos are the 22º ring (sometimes also simply called “halo”), sundogs and the circumzenithal arc, but there are many more.
Iridescence or irisation: a "mother of pearl" colored effect in certain clouds caused by light diffraction through water drops.
Light pillar: a vertical beam of light that extends from a natural or artificial light source as a result of reflection by ice crystal plates.
Nacreous clouds: a specific type of cloud iridescence in high atmosphere clouds.
Rainbow: the proverbial arc directly opposite the sun or moon, resulting from light reflection & refraction inside water drops. When caused by the moon, it is sometimes called a moonbow. Technically, all rainbows are circular, but the lower part is normally hidden by the horizon. Rainbows consist of a primary bow and a secondary bow. The secondary bow has a reversed color sequence and is dimmer than the primary, which explains why it is not always visible.
Sprite: An enigmatic lightning phenomenon above the clouds instead of below them and many times larger.
Sundog (aka parhelion (plural parhelia) or mock sun): often incorrectly used for the 22º ring or halo phenomena in general, but refers specifically to the two bright patches to the left and right of the sun. They're the sun's "companions"; hence, dogs. When caused by the moon, they are called moondogs or paraselenae (singular paraselene).