Go look at the moon

[Mitchell Koerner]

There's some huge moonbow right now that looks pretty wild. Probably 15deg radius.

It's visible from Sunnyvale and from Palo Alto but not from Hayward. Go check it out!

[Mitchell Koerner]

Correction, it's closer to a 24° angle between the moon and the edge of the circle.

[matthew marcus]

Nothing from Berkeley.
mam

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[Solomon Lucas]

Yes! Visible from Sunnyvale with a contrail thru it :-)

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[Donald Gardner]

It’s actually a lunar halo caused by moonlight refracting through ice crystals in high-altitude cirrus clouds. These hexagonal crystals behave like prisms forming a 22 degree halo.  A moon bow would be low in the horizon opposite the moon.

Here are two images from Los Altos.

 

On Mar 26, 2026, at 10:09 PM, Solomon Lucas <solomo...@gmail.com> wrote:



Yes! Visible from Sunnyvale with a contrail thru it :-)

<1000071070.jpg>

On Thu, Mar 26, 2026, 9:26 PM Mitchell Koerner <mfko...@gmail.com> wrote:

Correction, it's closer to a 24° angle between the moon and the edge of the circle.

On Thu, Mar 26, 2026, 9:10 PM Mitchell Koerner <mfko...@gmail.com> wrote:

There's some huge moonbow right now that looks pretty wild. Probably 15deg radius.

It's visible from Sunnyvale and from Palo Alto but not from Hayward. Go check it out!

<1000013884.jpg>

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[Dan Smiley]

from Mill Valley, folklore says count the number of stars within the halo, that's how many days until it rains

 

[Dan Smiley]

and this morning a Sun halo 

[Jamie Dillon, DDK]

That halo was stunning from Salinas. Jupiter and Procyon inside the halo made a lovely punctuation.

[Ted Hauter]

Possible 1 billion stars, within the halo arc minutes of sky.

On Fri, Mar 27, 2026, 1:32 PM Jamie Dillon, DDK <ngc1...@gmail.com> wrote:

That halo was stunning from Salinas. Jupiter and Procyon inside the halo made a lovely punctuation.

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[marek.c...@gmail.com]

I didn't see that particular halo around the Moon, but I've noticed some similar "22-degree" halos around the Sun recently.

If you've ever been interested in these sky-halo phenomena, I highly recommend the website linked below. It goes into amazing, wonderful detail about all of these types of phenomena and how they form. There's even a section on the sky haloes that might be visible in the atmospheres of other planetary bodies. The author also wrote a program (I think it's called "HaloSim") for simulating these phenomena in great detail.

https://www.atoptics.org.uk/

That site is a more precious resource than you might realize! I don't know if the author is still living; I think either they are not, or they stopped updating it some time ago, and their hosting service might have lapsed. At any rate, during the last few years the domain was taken over by someone who replaced the text with AI-generated text of far lower quality, which was much less informative. The site I linked above, with the beautiful diagrams and detailed explanations, was unavailable on the web for a while. It was a real shame.

I have no idea if there's any software that could save a whole site, with all its links and images, to your computer. But if you like the site, and didn't plan to do anything nefarious with your saved copy - in other words, if you really were just going to look at it yourself if the site ever goes away again - then you might consider trying to save it. If such a thing is even possible. That's my way of saying "The site is that good".

I don't see halo phenomena all that often, even though I look up at the daytime sky a lot. But I still really appreciate that site, and I hope to see the (many!) phenomena described in it someday.

[Ted Hauter]

Wow! What a find. 

Outstanding!

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[John Pierce]

On Sun, Mar 29, 2026 at 5:14 PM Ted Hauter <thgo...@gmail.com> wrote:

...

I have no idea if there's any software that could save a whole site, with all its links and images, to your computer. But if you like the site, and didn't plan to do anything nefarious with your saved copy - in other words, if you really were just going to look at it yourself if the site ever goes away again - then you might consider trying to save it. If such a thing is even possible. That's my way of saying "The site is that good".

...

if the sites content is basically static, and not dynamically generated, you can snag a copy off archive.org, at least if it was archived. 

[John Pierce]

oops, looks like archive.org didn't scrape this URL before 2025 and its the same weird mix of cool photos and funky AI generated spew.