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Full Moon - Unusually Big & Bright - May 5

Notrump

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Notrump
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The 2012 May Full Moon will reach its peak during the night of May 5-6. It will be the biggest and brightest since 2006 and until 2018 due to the greatest percentage of disk illumination virtually coinciding with perigee while the Moon hugs close to the ecliptic. The Full Moon’s geocentric angular diameter will be 33.5 arcminutes, and its geocentric brightness factor will be 1.055. See my panorama of fifteen 2012-13 Full Moons for comparisons: www.CurtRenz.com/moon

A Full Moon is typically twelve times brighter than a Half Moon due to the oppositional flash. That’s caused by direct reflection with minimal shadowing. The upcoming Full Moon will be even brighter. Enjoy the show!

Photos and descriptions of the May Full Moon would be welcome additions to this thread. Below is my shot of last month’s Full Moon taken from Arlington Heights, Illinois on 2012 APR 06 at 19:49 CDT.

FM120406.jpg
 
Notrump said:
The 2012 May Full Moon will reach its peak during the night of May 5-6. It will be the biggest and brightest since 2006 and until 2018 due to the greatest percentage of disk illumination virtually coinciding with perigee while the Moon hugs close to the ecliptic. The Full Moon’s geocentric angular diameter will be 33.5 arcminutes, and its geocentric brightness factor will be 1.055. See my panorama of fifteen 2012-13 Full Moons for comparisons: www.CurtRenz.com/moon
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Good! That means it will be overcast here on May 5th.

No rain, of course, but I'll take what I can get.
 
The image below is the full moon on March 8, 2012, as seen from Peoria, Illinois, USA. It was a quick grab for a lens test. Obviously there is no reference here for brightness or apparent size.

Moon2012-03-08.jpg

With a 30-40% chance of rain for this weekend it seems unlikely I'll get a shot of the May 5 full moon.
 
Twenty years ago I saw MIR transit the Moon.
Where will the ISS be on May 5?
Getting a shot of it transiting could be worth some money.
 
Ahhh.... I thought the moon looked very big when I was walking on the beach this evening.
 
GeeMack said:
The image below is the full moon on March 8, 2012, as seen from Peoria, Illinois, USA. It was a quick grab for a lens test. Obviously there is no reference here for brightness or apparent size.

With a 30-40% chance of rain for this weekend it seems unlikely I'll get a shot of the May 5 full moon.
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Nice photo, GeeMack, thanks for sharing. You're not far from those of us in Chicagoland, and we'll likely be floating in the same boat. ;)
 
Here's a fun illusion you all can try if you have a clear sky. When the Moon is on the horizon, many of us know the brain sees the Moon as larger because it is next to other things visible on the skyline. And when it is overhead the Moon looks smaller with no reference points.

Try this experiment. When the Moon is on the horizon, cover one eye. The 2D Moon will look instantly smaller. You can cover and uncover one eye to better see the instant size change.

Then ponder your bizarre brain that actually changes visual stimuli between your retina and your consciousness processing center. :)
 
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elgarak said:
Here's what our own Bad Astronomer has to say about it.

Verdict: It's not unusual. And not overly noticeable. Watch the moon even when it's not at the perigee!

Personally, I'e always liked half or three-quarter moons better for observation. Nice shadows. Better looking surface features.
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I certainly agree with you, elgarak, that through a telescope the Moon’s features are more interesting at phases other than full. However by naked eye a Full Moon is awesome, made especially so by the oppositional flash.

Plait may have some relevant points to make, but he is overlooking the fact that despite the May Full Moon appearing less than 1% wider than the April Full Moon, the May Full Moon will be 5% brighter due to nearness to the ecliptic. It will be 27% brighter than the upcoming December Full Moon. Enjoy the experience on Saturday, and don’t let guru wanabees throw cold water on it. ;)

Perigee and apogee are due to the Moon’s eccentric (Earth off-center) orbit. Emphasizing the fact that the orbit is also elliptical (non-circular) can be misleading in this context. We often see this irrelevant description from popular science writers, and Plait is no exception. This diagram of mine should clarify that: www.CurtRenz.com/LunarOrbit.JPG
 
elgarak said:
Here's what our own Bad Astronomer has to say about it.

Verdict: It's not unusual. And not overly noticeable. Watch the moon even when it's not at the perigee!

Personally, I'e always liked half or three-quarter moons better for observation. Nice shadows. Better looking surface features.
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Hilite by Daylightstar
The hilited part is not necessarily always true.
During a full moon, the true shape of formations like Montes Recti (Rukl 11) can be seen sort of indirectly. (Rukl map index)

When on or near (in local daylight) the terminator, this formation shows sharply defined boundaries between lit and unlit areas, suggesting that the formation is extremely rugged. During full Moon, when no shadows in that region can be seen, a good telescope operating at decent magnification will show the formation to consist mostly of rolling hills.
The various hillsides reflect sunlight in different directions under different angles enabling to differentiate between various hillsides (brightnesses), and the boundaries between directions of sunlight reflections (hillsides and valleys) are gradual, suggesting a more of a rolling hills landscape.


Another benefit from observing the full Moon is the possibility of observing lunar landscapes just inside the limb of the Moon with a bird's eye perspective, using high magnification (preferably with a wide angle eyepiece, for looking out of a space ship's porthole experience.

The visibility of areas like Mare Humboldtianum (Rukl 7) are subject to the Moon's libration, where what is otherwise (partly) invisible behind the Moon's limb, for instance mountains on the 'far' side of a mare, come into view.
Then, you are no longer looking down on the lunar surface but looking across the lunar landscape with a bird's eye perspective towards what is now no longer the limb of the Moon but the horizon.

All such features might be better observable as the Moon is somewhat larger now, which goes for all lunar detail as well.
 
Just on a quick note, the supermoon will probably wash out most of the Eta Aquariids (meteor shower derived from dust from Halley's comet). The Eta Aquariids will also be peaking on May 5th. The brightest ones should still be visible if you are away from city lights though.
 
This was at 21:15 taken near Peoria, Illinois. The Moon was 12° above the horizon, and it's still a little more than an hour from being 100% full...

Moon2012-05-05.jpg

Not much to look at with the Sun directly overhead, so to speak, because there's no angle of light to enhance the surface features. But measuring the image in the software it's just about as perfectly round as it ever gets.
 
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GeeMack said:
This was at 21:15 taken near Peoria, Illinois. The Moon was 12° above the horizon, and it's still a little more than an hour from being 100% full...

[qimg]http://1.bp.blogspot.com/-TeVk7d33Z0E/T6XnfqqPj7I/AAAAAAAAAQU/86vSDt3OStg/s1600/Moon2012-05-05.jpg[/qimg]​

Not much to look at with the Sun directly overhead, so to speak, so there's no angle of light to enhance the surface features. But measuring the image in the software it's just about as perfectly round as it ever gets.
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Thanks for sharing your fine photo, GeeMack. We're completely shut out here in relatively nearby Chicagoland. A solid sheet of clouds across the sky. So the cloud boundary must be between us. The group that gathered at the Adler Planetarium must be quite disappointed.

According to my calculations the greatest fraction of illumination of the Moon's apparent disk (fullest Moon) at 99.96% was expected for Chicago at 20:57 CDT. The time should have been very nearly the same in Peoria. A simplistic method of determining the moment of Full Moon by geocentric opposition from the Sun in ecliptical longitude is still used in almanacs and most other sources. Hence your belief that you were an hour early. Your photo was actually taken slightly after the time that the Moon appeared fullest over Peoria. ;)
 
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Notrump said:
According to my calculations the greatest fraction of illumination of the Moon's apparent disk (fullest Moon) at 99.96% was expected for Chicago at 20:57 CDT. The time should have been very nearly the same in Peoria. A simplistic method of determining the moment of Full Moon by geocentric opposition from the Sun in ecliptical longitude is still used in almanacs and most other sources. Hence your belief that you were an hour early. Your photo was actually taken slightly after the time that the Moon appeared fullest over Peoria. ;)
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Yeah, I thought it looked a little thin. :D
 
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