No Full Moon for Australia in February 2010

[ngcles]

Hi All,

I ran across an article in the Sydney Morning Herald yesterday (28122009) proclaiming that a "Blue Moon" occurs on New Years Eve, December 31st 2009 -- being the second full moon of the month of December.

The item is here:

http://www.smh.com.au/national/something-in-the-sky-on-new-years-eve-happens-once-in-a-blue-moon-20091227-lgae.html

There is a some dispute as to the exact meaning of the term "Blue Moon". The most popular meaning is a 2nd full moon in a calendar month. However, the most likely strictly correct one (but not well known) is explored in an article in the 1999 edition of Sky & Telescope Magazine by Phillip Hiscock, relying on the first known usage of the term in the Maine Farmers Almanac, where a "Blue Moon" was the defined as the third Full Moon within a season that contained four Full Moons.

In fact for all Australian time zones (according to either definition) this New Year's Eve will not be a Blue Moon because Full Moon is at 19:14 UTC on 31st December and it will therefore occur at 6.14am AEDST on the 1st of January 2010. For 3/4ths of the world, they will get a Blue Moon on December 31st -- but not Australia. ie all time zones between UTC +6hrs and +11 hrs will not have a blue moon, all other time-zones will have a blue moon on New Year's Eve.

Our (Australian) "Blue Moon" will actually occur on 30 January 2010 (by the first and most popular definition of the term Blue Moon).

But in looking at that question, another arose -- February 2010. If a "blue moon" is uncommon or rare, even rarer (much, much rarer in fact) is a calendar month without a Full Moon at all. These can only occur in the month of February because a Synodic Month (for practical purposes here), is the period between two full moons and is just over 29.5 days on average. All other calendar months have 30 or 31 days -- longer than the Synodic Month and so therefore must contain at least one Full Moon.

Therefore in the month of February 2010, using Australian time zones, there will be no Full Moon at all. Great news for all deep-sky observers and astro-imagers (just kidding!).

Full Moons are 5:18pm AEDST 30th January 2010 and then 3:38am AEDST 1st March 2010.

How rare is that?? Much, much rarer than a Blue Moon that happens on average every 2.5 years-odd.

What's more, we'll get a second Blue Moon in a calendar year (according to Australian Time Zones) at the end of March. So Jan 2010 we get two Full Moons, February 2010 -- no Full Moon, then March 2010 -- two Full Moons again (using the most popular definition). Wow!

So, when was the last February without a Full Moon?

I'm waiting for someone to tell me ...!



Best,

Les D

[Nightskystargaz]

Les D,

I thought there was a full moon for Feb. I'll look at my charts, when I get home from the Library.

Happy New Year to you.

:thanx:,

Tom

[tlgerdes]

I'd prefer a moon cycle with two new moons in a month. :D

Les can you look into the crystal ball and tell us how far into the future we have to wait for that one?

[ngcles]

Hi All,

Seems like someone at the Sydney Morning Herald was listening ...

http://www.smh.com.au/technology/oops-that-nye-moons-not-really-blue-20091229-lify.html

... but it also seems that " ... astronomers shouldn't make a big fuss of the technical details."

Hmmm ...


Best,

Les D

[michaellxv]

From the same article.

" but the last time February had no full moon was 1991. It is not due to occur again until 2018. "

Do I see a pattern developing there?

[Robh]

A Full Moon will occur roughly midway date-wise between two New Moons. So all you need to do is look for a Full Moon around the middle (15th or 16th) of a month.
In 2011, there is a Full Moon on Jul 15th and a New Moon on Jul 1st and Jul 30th. In 2014, there is a Full Moon on Mar 16th and a New Moon on Mar 1st and Mar 30th.

Regards, Rob.

[AstralTraveller]

Les, thanks for the post, particularly the bit about Feb. I knew about it being the only possible candidate but I didn't know about it happening.



Well he did go on to say ".....but anything that gets people outside looking at the sky is a good thing." and so redeemed himself.

BTW an old song just popped into my head (nature abhors a vacuum ;)) singing "by the light of a silvery moon". I've always thought of the moon as white (or very bright gray) and lacking a metallic sheen. Can you tell me why the moon would appear silvery and how often this happens????? :P:P:P

[ngcles]

Hi Dave,



On that reasoning the "Mars-Hoax" email that goes around every year regarding August 28th and Mars looking as big as the Full Moon, would also be a "good thing" because "anything that gets people outside looking at the sky is a good thing".

Sorry, I can't subscribe to that species of reasoning. For mine it goes in the same bucket as "Never let the facts get in the way of a good story ..."



I dunno the answer to this off the top of my head -- so I'll have so see if I can find a proper answer from somebody who knows better than I.

The Moon has a very low albedo and only reflects about 7% of the light hitting it. This is about the same reflectivity as newly-laid bitumen. So why doesn't it look completely black?

My guess (without having a proper answer at the moment) is that it is a function of having a very dark sky to view it in (at night anyway) and its size. The Moon doesn't look bright in the day becasue the surface-brightness of the sky virtually matches it.

The reflectivity of the Moon also varies from phase to phase depending on how much of the darker maria are on view and how much of the brighter highlands are on view. Another factor is that near Full Moon there are few if any shadows and we "face the Moon squarely" -- so to speak, so it has a higher surface-brightness per unit of illuminated area and the Sun is shining directly down on the Moon rather than being an oblique angle of illumination.

Silvery -- yep it does look kinda-that way to me naked eye but more like alabaster through the telescope I'd reckon. In fact I've just finished taking a look at it through the telescope in the backyard and my wife thought it looked like plaster of paris.

But in the end, my guess is that "silvery" is in the lyric because they needed a three syllable word that fitted the meter of the lyric and beat. "white-y" or "alabaster-y just doesn't cut the mustard!;)

Yes, I look at the Moon through a Telescope! (Gasp!!) Almost unbelievably, my wife looked tonight too. (Double Gasp!!)

I took a look tonight in particular because I wanted to check everything with the ArgoNavis/Servocat was okay (the Argo just had a service call) and I was interested to see Schroter's Valley -- and the angle of illumination on that part of the Moon just happened to be right. Looked very nice at x371 !!

http://the-moon.wikispaces.com/Schroter's+Valley

One of the most interesting bits on the Moon I think.

The seeing tonight is also quite good -- could split Sirius (ie see the "pup") at x317 with little difficulty. And I also wanted to see a couple of O.C's I'm researching too.


Best,

Les D

[snarkyboojum]

I'm really glad I stumbled across this post. I found myself watching the news on TV this morning and heard a news presenter going on about the 'blue moon' tonight. She even came up with the preposterous idea that the moon would look blue "with enough pollution" in the sky.

I wonder who vets this stuff before it hits TV. Hilarious really. Perhaps not a bad conversation piece to get people talking about astronomy though (especially if someone is at hand to explain the real story).

Great info in this post though. Cheers!

[ngcles]

Hi All,

The below link takes you to a page by Dr Nick Lomb, Sydney Observatory that indicates the dates for all "Blue Moons" (according to the most popular definition) between now and 2050 for observers in the Australian Eastern Standard Time Zone.

http://www.sydneyobservatory.com.au/blog/?p=458

If you live elsewhere or it is daylight-saving, your milage may vary ...

And yes Snarkyboojum, so far as popular-media is concerned in Australia (and most of the rest of the world for that matter), it just goes to show that once the genie is out of the bottle, it's damned hard to get it back in.


Best,

Les D

[mithrandir]

Editor and reporters still go by the adage:

Never let facts get in the way of a good story.

[Analog6]

Yes, I've been growling at the newsreaders all week - my OH is a former reporter and he says once they've said it, if it sells papers it stays!

I am looking forward to the 2 BMs in January & March.

Thomas, there probably IS a full moon in February for Texas, due to the time difference.

[bethmercado2112]

Hi there, This "no full moon in Australia" still confuses me. I would appreciate if you enlighten me on this.

According to Geoscience Australia (http://www.ga.gov.au/geodesy/astro/moonphases/phase2010.jsp), the full moon in Australia is on FEB. 28. 2010 at 16 h 35 m.

The only month in recorded history that did not have full moon was on FEB 1865.

E. Mercado

bethmercado2112@yahoo.com

[Rob_K]

Hi Elizabeth! That time is UT. Here in the east, I'm UT+11 so that pushes the full moon into March. Even in the furthest west of Australia, the time zone is UT+8, which still pushes it into March by 35 min!! :thumbsup:

Cheers -

[ngcles]

Hi bethmercado2112,



When you look at the table on that web-site you will see the times are in UTC (Universal Coordinated Time) -- that is for all intents and purposes Greenwich Mean Time.

At this time of year in Australia with daylight savings in operation (in some places) the states of the Australian mainland are between 8 and 11 hours ahead of UTC so Feb 28th 16:28 UTC when you add between 8 and 11 hours always brings you into the early hours of 1st of March. For all time zones between +8 and +11 UTC, there will be no Full Moon in February.

These time zones bascially include all New Zealand, Australia, and most of east Asia (Japan, China, Korea, Indo-China, Malaysia, Indonesia & India) -- including about 1/2 the world's population BTW. But, does not include Central Asia, Europe, Africa, North or South America. In the USA, because you good folks are (from memory) about 6 to 8 hrs behind UTC don't get a full-Moonless Feb -- this time.

The Full-Moonless month thing can only happen in February because it is the only month shorter than the Moon's average Synodic Period. The Synodic period is the period between *exact* phases of the Moon (eg Full Moon to Full Moon) in successive months (lunations). It is on average 29.5 (odd) days.

See Synodic Month: http://en.wikipedia.org/wiki/Synodic_month#Synodic_month

(Short Extrract)

Synodic month
This is the average period of the Moon's revolution with respect to the sun. The synodic month is responsible for the moon's phases, because the Moon's appearance depends on the position of the Moon with respect to the Sun as seen from the Earth. While the moon is orbiting the earth, the Earth is progressing in its orbit around the Sun. This means that after completing a sidereal month the Moon must move a little farther to reach the new position of the Earth with respect to the Sun. This longer period is called the synodic month (Greek: σὺν ὁδῴ, sun hodō, meaning "with the way [of the sun]"). Because of perturbations in the orbits of the Earth and Moon, the actual time between lunations may range from about 29.27 to about 29.83 days. The long-term average duration is 29.530589 days (29 d 12 h 44 min 2.9 s). The synodic month is used in the Metonic cycle.

The Moon's orbital cycle repeats approximately every 19 years and is known as the Metonic Cycle.

http://en.wikipedia.org/wiki/Metonic_cycle

The Full-Moonless February thing is as a result of the resonance between the Synodic Period, the length of February (28 or 29 days) and the Metonic Cycle and so repeats on average every 19 years-odd (your milage may vary according to time zone!)

Hope this helps Beth.:thumbsup:


Best,

Les D

[Waxing_Gibbous]

Unless you are doing detailed observations of Luna (and big props to you if you are!), it's a distinction without a difference.
I'm half blind and have cracking headache from spending 3 hours looking at it last night. And that's with 2 filters stacked.
Ouch