Freethought & Rationalism Archive

Kuu · 12-20-2002, 02:08 AM

While holidaying at Southport, a town about 100 km south of Hobart Tasmania, I was lucky enough to see a very clear and beautiful moonbow. It was a very calm night and iy was drizzling. I saw the moonbow across the sea. It was silvery with a touch of the colours of the rainbow.

I have done a search on the Internet and found only a few mentions of this phenomena.

and some photos

<a href="http://www.hawaii.ne.jp/bigisland/moonbow/moonbow.htm" target="_blank">http://www.hawaii.ne.jp/bigisland/moonbow/moonbow.htm</a>

<a href="http://www.grandcanyonphotography.com/cf/images/lightning/moonbow200.jpg" target="_blank">http://www.grandcanyonphotography.com/cf/images/lightning/moonbow200.jpg</a>

I can only find mention of moonbows being seen across the sea in Hawaii and Tasmania. The photo above of the Grand Canyon above seems to be lit by lightning so might not be a true moonbow. Moonbows are occasionally seen across waterfalls, most notably the Cumberland Falls in the USA.

What I would like to know is why are they so rarely seen? I would expect them to be seen less than rainbow but surely the conditions to see them should occur more often then it seems to.

Also why would they be seen more often in Hawaii and possibly Tasmania?

Herman Hedning · 12-20-2002, 05:06 AM

I guess this is not directly related to your post - I must admit I never heard the word moonbow before - but it got me thinking about other halo fenomena. Here is a famous painting from 1535 of a very complex halo fenomenon. Needless to say, this caused quite an uproar at the time since it was seen as a "sign" from the man above, or perhaps from the chap below.

seebs · 12-21-2002, 08:28 AM

I see subtle ones all the time in winter in Minnesota, assuming we're talking about the same thing. They're not always very visible.

One of the last sane · 12-21-2002, 07:52 PM

I would think you'd only be able to see them on very bright nights, because your color vision generally shuts down in poor light. The receptors that detect color require more light than the others.
I saw a moonbow many years ago when I was a kid, but the moonbow I saw had no colors in it. It was a perfect arc of milky white, on the horizon after light rain, same sort of conditions you'd see a rainbow during the day. The moon had risen. Can't remember much more than that except it was way out in the middle of nowhere so I'm fairly sure it wasn't some manmade phenomenon.

Jackalope · 12-22-2002, 01:23 AM

The terms you should be looking for are moondog, lunar halo, and tangental arc. I'm still looking for a good image, but the effect is most noticeable when there are ice crystals high in the atmosphere (explains why you see them a lot in the midwest).

I'm still searching for a good online image...
Found a good big one at the Wellington Astronomy Society's <a href="http://astronomy.wellington.net.nz/images/gallery/Moss-Paul/020218-moon/big-moondog1w.jpg" target="_blank">image gallery</a>

Kuu · 12-22-2002, 02:28 AM

I think we are talking about here are two different phenomena. The first is the halo around the moon that Herman Hedning and Jackalope have mentioned and the second is a moonbow (rainbow at night) that I and One of the last sane have seen.

My bow didn't surround the moon. The full moon was shining above it as far as I recall. Strangely I thought it was a silver arc until I had watched it for a minute or so and saw the faint colours. Maybe that is because it took my eyes a while to adjust to the darkness.

[ December 22, 2002: Message edited by: Kuu ]</p>

One of the last sane · 12-22-2002, 04:04 AM

What Kuu said. What I saw was not a halo around the moon, which had already risen, but a faint white rainbow at night. Maybe I didn't watch it long enough to see the colors.

Mageth · 12-22-2002, 01:43 PM

<a href="http://home.hiwaay.net/~krcool/Astro/moon/moonring/" target="_blank">moon light effects</a>

<a href="http://www.soilsci.ndsu.nodak.edu/enz/picts/mdog.html" target="_blank">moon dogs</a>

I once saw a <a href="http://www.science-frontiers.com/sf068/sf068g14.htm" target="_blank">double moon</a> similar to this guy's account on a cold winter's night. I had to bring my wife outside to verify that I wasn't seeing things. But I can't guarantee that the effect was not some physiological/psychological phenomenon.

12-20-2002, 02:08 AM	#1
Kuu Senior Member Join Date: Jul 2002 Location: Tasmania Posts: 710	Moonbows While holidaying at Southport, a town about 100 km south of Hobart Tasmania, I was lucky enough to see a very clear and beautiful moonbow. It was a very calm night and iy was drizzling. I saw the moonbow across the sea. It was silvery with a touch of the colours of the rainbow. I have done a search on the Internet and found only a few mentions of this phenomena. and some photos <a href="http://www.hawaii.ne.jp/bigisland/moonbow/moonbow.htm" target="_blank">http://www.hawaii.ne.jp/bigisland/moonbow/moonbow.htm</a> <a href="http://www.grandcanyonphotography.com/cf/images/lightning/moonbow200.jpg" target="_blank">http://www.grandcanyonphotography.com/cf/images/lightning/moonbow200.jpg</a> I can only find mention of moonbows being seen across the sea in Hawaii and Tasmania. The photo above of the Grand Canyon above seems to be lit by lightning so might not be a true moonbow. Moonbows are occasionally seen across waterfalls, most notably the Cumberland Falls in the USA. What I would like to know is why are they so rarely seen? I would expect them to be seen less than rainbow but surely the conditions to see them should occur more often then it seems to. Also why would they be seen more often in Hawaii and possibly Tasmania?

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12-20-2002, 05:06 AM	#2
Herman Hedning Regular Member Join Date: Jun 2001 Location: Sweden Posts: 189	I guess this is not directly related to your post - I must admit I never heard the word moonbow before - but it got me thinking about other halo fenomena. Here is a famous painting from 1535 of a very complex halo fenomenon. Needless to say, this caused quite an uproar at the time since it was seen as a "sign" from the man above, or perhaps from the chap below.

12-21-2002, 08:28 AM	#3
seebs Contributor Join Date: May 2002 Location: Saint Paul, MN Posts: 24,524	I see subtle ones all the time in winter in Minnesota, assuming we're talking about the same thing. They're not always very visible.

12-21-2002, 07:52 PM	#4
One of the last sane Senior Member Join Date: Jun 2002 Location: hereabouts Posts: 734	I would think you'd only be able to see them on very bright nights, because your color vision generally shuts down in poor light. The receptors that detect color require more light than the others. I saw a moonbow many years ago when I was a kid, but the moonbow I saw had no colors in it. It was a perfect arc of milky white, on the horizon after light rain, same sort of conditions you'd see a rainbow during the day. The moon had risen. Can't remember much more than that except it was way out in the middle of nowhere so I'm fairly sure it wasn't some manmade phenomenon.

12-22-2002, 01:23 AM	#5
Jackalope Veteran Member Join Date: Oct 2002 Location: Hayward, CA, USA Posts: 1,675	The terms you should be looking for are moondog, lunar halo, and tangental arc. I'm still looking for a good image, but the effect is most noticeable when there are ice crystals high in the atmosphere (explains why you see them a lot in the midwest). I'm still searching for a good online image... Found a good big one at the Wellington Astronomy Society's <a href="http://astronomy.wellington.net.nz/images/gallery/Moss-Paul/020218-moon/big-moondog1w.jpg" target="_blank">image gallery</a>

12-22-2002, 02:28 AM	#6
Kuu Senior Member Join Date: Jul 2002 Location: Tasmania Posts: 710	I think we are talking about here are two different phenomena. The first is the halo around the moon that Herman Hedning and Jackalope have mentioned and the second is a moonbow (rainbow at night) that I and One of the last sane have seen. My bow didn't surround the moon. The full moon was shining above it as far as I recall. Strangely I thought it was a silver arc until I had watched it for a minute or so and saw the faint colours. Maybe that is because it took my eyes a while to adjust to the darkness. [ December 22, 2002: Message edited by: Kuu ]</p>

12-22-2002, 04:04 AM	#7
One of the last sane Senior Member Join Date: Jun 2002 Location: hereabouts Posts: 734	What Kuu said. What I saw was not a halo around the moon, which had already risen, but a faint white rainbow at night. Maybe I didn't watch it long enough to see the colors.

12-22-2002, 01:43 PM	#8
Mageth Contributor Join Date: Jul 2001 Location: Deep in the heart of mother-lovin' Texas Posts: 29,689	<a href="http://home.hiwaay.net/~krcool/Astro/moon/moonring/" target="_blank">moon light effects</a> <a href="http://www.soilsci.ndsu.nodak.edu/enz/picts/mdog.html" target="_blank">moon dogs</a> I once saw a <a href="http://www.science-frontiers.com/sf068/sf068g14.htm" target="_blank">double moon</a> similar to this guy's account on a cold winter's night. I had to bring my wife outside to verify that I wasn't seeing things. But I can't guarantee that the effect was not some physiological/psychological phenomenon.

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