Saturday, March 26, 2011

Moon Song

   from a photographer's notebook...

The "Super Moon" rises above the Potomac   ©2011 Steve Ember

Most of us who enjoy the beauty of a moonlit night don’t think in terms of “apogee” or “perigee.”

Those terms are for astronomers – not songwriters, romantics…or photographers. Songwriters have waxed poetic over “harvest moons” – as in Shine on, Harvest Moon, for me and my gal…Blue Moon – you saw me standing alone, without a dream in my heart; without a love of my own. Oh, You Crazy Moon, look what you’ve done.  MoonglowHow High the MoonMoon Song, Moon Over Miami... But admit it - you’ve never heard a song about the moon’s apogee…or perigee…

Me, I didn’t know the difference, or much care about it…until a friend who knew my photography, alerted me to the Super Moon that was to rise here in Washington at 7:39 PM last Saturday evening. 

What was so special about this particular moonrise?  One word: Size. Yes, size matters when one is including the moon in a nightscape type of photograph. And I have any number of favorite spots in our nation’s capital for capturing a moonrise.  One is on the Virginia side of the Potomac, where one can see a panorama that includes the U.S. Capitol, the Washington Monument, and the Lincoln Memorial, all nicely arrayed before one’s lens…just waiting to be adorned by a great big full moon.  My preference tends to be the big orange colored “harvest moon” of the type we see around here in autumn.

If you’re a photographer, or just a moon-loving romantic, you are certainly aware of the fact that the moon – especially the full moon – looms much larger when it is close to the horizon.  In other words, shortly after moonrise. And if you’re a traditionalist behind the camera, you like to capture that fullness as it actually appears, and not use Photoshop or other technical wizardry to make the moon take up five times as much space in your photo.  Fun, perhaps…but kinda bogus.

There is also the consideration that while the moon always rises in the east, the actual point in the sky will vary…and that, of course, affects where it will appear in your photograph, composition-wise. And, if it’s going to be a full moon – and your (photographic) stars are in alignment, such that it will be just where you want it, but a big bank of storm clouds or other meteorological impediment should rain on your parade, what then?

One begins to see why some photographers diss Mother Nature and cut and paste that full moon…

So, imagine my glee at the weather conditions Saturday evening.  Dry, comfortable temperatures, and superb visibility from my chosen viewing point, as I arrive, set up my tripod, latch on the camera, and compose my view.  Dome of the Capitol at the left, nicely lighted…the spire of the Washington Monument equidistant between the Capitol dome and the crisp, brightly lit columns of the Lincoln Memorial in the center, casting its reflection in the indigo, almost still Potomac

Just a few minutes to consider the differences between apogee and perigee and their bearing on something called the “Super Moon.” No, I hadn’t heard that term before.  Was I not paying attention back in 1993?  That was the last time a full moon – at perigee – paid us a visit. Well, maybe we didn’t know to name it back in ’93… But it was there.  And it was soon to be here. And best to catch it, as the phenomenon will not re-occur for another 18 years or so.

Now, this is not to say songwriters, romantics, and photographers will have to wait 18 years to be enchanted by a big orange full moon rising majestically over our favorite masterpiece of nature or architectural landmark. And we photographers, through judicious selection of varying degrees of telephoto lens perspective, will be able to make that moon as large – and as textured – as fine optical glass and a solid tripod can provide.

But, back to what made the Super Moon so dramatic…and so very unique.
Our Moon travels around the Earth in an elliptical orbit, and that elliptical path happens to have a farthest point – called the “apogee,” and a nearest point, called the “perigee.” Now, according to NASA, moons at perigee appear 14% larger and 30% brighter than moons at apogee.

But … a perigee moon almost coinciding with a full moon … that is what all the fuss is about.  Technically speaking, a full moon is only a “full” moon for an instant.  On either side of that tiny time point, it is not quite exactly its perfectly round, uniformly bright self.  But let’s not quibble over such minutiae.  I mean, I’m going to leave my sextant and measuring tape at home.

As you can see in my Washington photos, the (OK, nearly!) full moon presented itself as a big orange disc while still low to the horizon.  As it rose, it would become both smaller and whiter.  And if you viewed it, say, at 8:39 PM (an hour after it appeared), it looked pretty much like any other full moon in a nice clear sky.

Mighty big when it first appears!     ©2011 Steve Ember
And that gets us back to why the relatively few minutes after moonrise were so visually dramatic – a “Super” moonrise, if you will. For at the point where this (almost!) full moon is at perigee, a sort of optical illusion I will not pretend to understand, or even try to explain, makes it look truly formidable. One can only imagine the primal fears it inspired in our hunter-gatherer forbears as they went about with their clubs in search of dinner on the hoof. 

A glowering fiery orange…mass…on the horizon. Out of all proportion to any harvest moon we’ve admired.  Or sung about. Or photographed.  To present such to you myself, I would have had to be on higher ground with a much longer lens than the telephoto I was using Saturday, in order to get a clearer shot at the true horizon. And that would have precluded capturing the panorama you see above. 

On the web, you’ll find many such dramatic shots with the moon supernaturally large, during that very brief phase, at and just above the horizon, which most precisely defines a “Super Moon.”
      While looking perhaps a bit less "super," by 8:17, the moon has risen sufficiently to cast a nice reflection in the Potomac.      ©2011 Steve Ember               

Incidentally, have you ever wondered how much the moon climbs in the sky in, say, thirty seconds?

Typically, when I’m shooting after-dark cityscapes, I will use time exposures of varying lengths, favoring a small aperture for best depth of field and capture of the lights in the buildings, street lighting, traffic, etc., as well as capturing some nice “starbursts” in those lights.  The smaller the aperture, of course, the greater the interval the shutter must stay open. Fortunately Saturday, in most of my shots, I was conservative as to those l-o-n-g  exposures, preferring to shoot many bracketed sets to get just the right lighting during a fairly short window in which the moon was still large and in the proper space within my composition. 

But I did shoot one frame with a teeny-tiny f/stop and (according to the EXIF data recorded by my camera) a shutter duration of 30 seconds. Look closely at the photo below and you will see some “ghosting” around the moon, showing just how much it rose in the sky in those 30 seconds!
In this 30-second exposure, you can see  just how much the "super moon" rose in that interval.     ©2011 Steve Ember
By the way, speaking of sublime lunar experiences, have you ever heard the sublime Sue Raney singing "Moon Song?"


©2011 Steve Ember 
I will be offering a number of my "Super Moon over Washington" nightscapes as Photo Note Cards and gallery prints in various sizes.  For a higher quality view, please go to my fotocommunity site and click on the Nightscapes-US folder to see more.

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