What causes a blood-red moon? - DPChallenge Forums

Fisher Price Kid-Tough Digital

06/08/2009 02:25:02 AM · #1

For the astronomers of DPC what, other than eclipse or smoke, causes a blood-red moon? When it came up it was deep orange and an hour later it's darker both in colour and in luminence. I don't know of any fires around, there's not an eclipse for another month, and it's totally clear and sharp, just dark red... It's kinda spooky!!

This is a terrible shot, quickly grabbed with the S2IS, handheld, but it gives a good idea of the colour, anyway.

Bugzeye

06/08/2009 03:15:52 AM · #2

Haze in the atmosphere... strangeghost or kirbic will probably give you exact answers tomorrow if you keep the thread on front page.

Nikon AF Nikkor 50mm f/1.4D

06/08/2009 03:24:56 AM · #3

Thanks, I'll make sure to bump it in the morning.

I know we got moons more like that on the prairie at harvest time, from all the dust and such being stirred up, and I've seen them orangey-red when there's forest fires but I couldn't find any info on fires that may have sent smoke this way, no volcanic action, nothing I can think of. We're on the coast so not dusty, it's insanely clear out tonight, stars are bright as always, only thing unusual is the blushing moon. Two hours after rising, when it's normally brilliant white it's faded now to a warm orange. But honestly, it was so dark that it did look just like an eclipse. I can't recall ever in my 45 years living here seeing it like that.

MistyMucky

Nikon D700

06/08/2009 04:55:44 AM · #4

It could be any aerosol. If it's not smoke or dust, it could be pollution, or a thin mist I guess.

aliqui

Nikon D300s

Nikon AF-S Nikkor 70-200mm f/2.8G ED VR II

06/08/2009 04:57:22 AM · #5

WikiAnswers

kirbic

Canon EOS R5

Canon RF 24-70mm f/2.8 L IS

06/08/2009 07:38:06 AM · #6

Aerosols, definitely. And very small ones, like smoke. They must be small enough to scatter blue light more than red, so that means they are sub-micron particles.

scooter97

Canon EOS-6D

Canon EF 100-400mm f/4.5-5.6L IS

06/08/2009 08:04:58 AM · #7

I think the atmosphere in general bends the light waves at the horizon. This has a filtering effect on some of the color spectrum. It's the same thing with sunrise and sunset.

This was taken 2 full moons ago.

kirbic

Canon EOS R5

Canon RF 24-70mm f/2.8 L IS

06/08/2009 11:22:33 AM · #8

Originally posted by scooter97:

I think the atmosphere in general bends the light waves at the horizon. This has a filtering effect on some of the color spectrum. It's the same thing with sunrise and sunset.

This was taken 2 full moons ago.

The redness near the horizon is due to the increased distance through the atmosphere that the light travels. Scattering of the light by the gas molecules in the atmosphere is mostly responsible. This is called Rayliegh scattering. When a red moon persists well above the horizon, then some very fine aerosol is responsible. In order to preferentially scatter blue light, the particles must be very small, a couple tenths of a micron or less. Most atmosphereic aerosols are larger than this, but some (like smoke) can be smaller.

GeneralE

Canon PowerShot S3 IS

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/08/2009 12:34:18 PM · #9

If it helps any (it won't) I believe I heard on the radio yeaterday that the Full Moon nearest the Summer Solstice (it occurred yesterday at about Noon in the Pacific time zone) is traditionally named the "Strawberry Moon."

citymars

Nikon D700

Nikon AF-S NIKKOR 24-70mm f/2.8G ED

06/08/2009 12:34:24 PM · #10

Originally posted by BeeCee:

What causes a blood-red moon?

The ascension of Iblis The Thrice-Damned?

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/08/2009 02:48:29 PM · #11

Originally posted by GeneralE:

But that's because it's strawberry season, no? My farmer's almanac calendar names the moon for each month. July is the buck moon and September is corn etc.

Thanks, guys, for the answers. I just found it so strange when it darkened as it got higher in the sky instead of lightening. After 5 hours it had finally made it to silver. When I couldn't think of an obvious source of the aerosols I just wondered if there were another cause I didn't know about.

Hmmm, I wonder if it's some of the China pollution? NASA says it's worst in spring and our inflow is usually across the Pacific. Ah well, I guess I'll never know, but it was cool to see.

Thanks again for responding; one of the reasons I LOVE DPC! :)

GeneralE

Canon PowerShot S3 IS

06/08/2009 03:20:11 PM · #12

Originally posted by BeeCee:

Originally posted by GeneralE:
If it helps any (it won't) I believe I heard on the radio yeaterday that the Full Moon nearest the Summer Solstice (it occurred yesterday at about Noon in the Pacific time zone) is traditionally named the "Strawberry Moon."

But that's because it's strawberry season, no? My farmer's almanac calendar names the moon for each month. July is the buck moon and September is corn etc.

Exactly -- that's why I said it wouldn't actually help with your original question. :-)