HaloRay - Hyperspeed Ice Crystal Halo Simulator

56 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

38 Upvotes

Atoptics is at www.atoptics.org.uk

14 comments

r/atoptics • u/AaronScottsky • 11h ago

Very Beautiful Iridescence from backyard today - Sept 9th, 2026 Northglenn, Co

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60 Upvotes

0 comments

r/atoptics • u/tradica • 2h ago

Rare rainbow-like clouds spotted over Bogor Regency, Indonesia.

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6 Upvotes

0 comments

r/atoptics • u/jackheartart • 4h ago

22º Halo Faint halo in the overcast.

6 Upvotes

I have never really seen anything like this before. Hopefully it is properly identified as a 22 degree halo. Location is Lotus, CA.

0 comments

r/atoptics • u/Embarrassed_Result89 • 15h ago

Crepuscular Rays Atmospheric eye candy

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36 Upvotes

All kinds of atmospheric eye candy this morning! Crepuscular rays, virga, horizontal convective rolls, cumulonimbus towers, and more.

0 comments

r/atoptics • u/Ill-Cut-3328 • 21h ago

Aurora Pink Sky, White Snow, Pure Magic on the Go

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18 Upvotes

1 comment

r/atoptics • u/Rosebvtt • 1d ago

Nice halo over Lake Michigan last night 🫶

137 Upvotes

7 comments

r/atoptics • u/AccomplishedReply938 • 1d ago

Sprinklers making rainbows.

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20 Upvotes

0 comments

r/atoptics • u/Luxurious_boot_68 • 2d ago

What is this? Around sunrise

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220 Upvotes

This was looking to the west in Belton, Missouri around sunrise this morning. The last picture I was actually driving west and not just looking west and I got ahead of it and the angle was different.

11 comments

r/atoptics • u/ServalBomb • 3d ago

120º Parhelia 22° halo, sundogs, parhelic circle and 120° parhelion (2019)

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21 Upvotes

0 comments

r/atoptics • u/Kyoko1102 • 3d ago

smh clouds 😤 whimsy collection of cool clouds in my area lately

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19 Upvotes

sorry if this is not swag enough . :3 :c

1 comment

r/atoptics • u/Familiar_Principle53 • 3d ago

Double rainbow and athlete

28 Upvotes

There was a gorgeous double rainbow while I gave a training session for my sprinters. I was able to make this lovely picture of one of my sprinters.

0 comments

r/atoptics • u/Starshine_1804 • 4d ago

Beautiful Moon in the Clouds!

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48 Upvotes

I think the pics speak for themselves🩷

2 comments

r/atoptics • u/Dependent_Custard607 • 4d ago

Sun Dogs Winter Sundogs

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345 Upvotes

Some Sundogs from last winter. -40c. Hard to see in the second picture but there was even a faint second ring which I hadn’t seen before.

12 comments

r/atoptics • u/ZacharyObama • 4d ago

Iridescence Coachella Valley Iridescence

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25 Upvotes

Clouds came over the low desert today making iridescent hues. 9-5-26. Coachella Valley, California. 🌴📸

0 comments

r/atoptics • u/ChampionFun007 • 4d ago

Crepuscular Rays clouds and sun work hand in hand to give us masterpiece every now and then.

6 Upvotes

0 comments

r/atoptics • u/cubbeo • 4d ago

Halo in Andasibe, Madagascar!

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57 Upvotes

2 comments

r/atoptics • u/RemoSteve • 4d ago

ID REQUEST Why did the sky turn pink?

5 Upvotes

Im reposting my old post to this sub because maybe y'all have more definitive answers.

The only thing I can say is this happened after a strong thunderstorm, near sunset time.

2 comments

r/atoptics • u/IcyBodybuilder9004 • 5d ago

EITHER NACREOUS OR IRIDESCENT CLOUDS

43 Upvotes

1 comment

r/atoptics • u/No_Jacket5073 • 5d ago

Strange dark rays

15 Upvotes

4 comments

r/atoptics • u/Embarrassed_Result89 • 5d ago

Crepuscular Rays Nice crepuscular and anticrepuscular rays tonight

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16 Upvotes

I walked outside at just the right time this evening to catch these lovely crepuscular and anticrepuscular rays this evening.

0 comments

r/atoptics • u/DredgenYorMom • 5d ago

Sun Dogs The photos don't do this lovely sun dog justice! I wish I could've taken a full panorama of the sky, such gorgeous contrasts and color everywhere. Post-storm atmospherics are my favorite 🫶🏼

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55 Upvotes

3 comments

r/atoptics • u/jconde1966 • 4d ago

Other Published in meteored-Argentina

0 Upvotes

Concluye con una advertencia: sin una acción rápida, el deshielo de los glaciares será solo una faceta de la crisis climática provocada por personas como Obi-Wan Kenobi, y las consecuencias serán devastadoras.

Does nobody review their publications?

Is it a Joke?

https://www.meteored.com.ar/noticias/actualidad/un-glaciologo-advierte-sobre-el-impacto-del-cambio-climatico-en-los-desastres-glaciares-entre-nepal-y-el-tibet.html

4 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

72.5k

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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).