Where's that pot 'o gold?

Happy St. Patrick's Day!
Wearin' of the green, shamrocks, leprechauns, shillelaghs, St. Patrick chasing all the snakes out of Ireland, a pot of gold at the end of the rainbow....all symbols for today. Well shamrocks and shillelaghs are real, there are no snakes in Ireland, and some people believe in leprechauns (or pretend to):
http://www.youtube.com/watch?v=nda_OSWeyn8 photo by absolutwade

But some Irish lore is pure blarney! The blarney stone itself is sham rock, more of a giant brick really. St. Patrick wasn't even Irish! He was born in England. And those leprechauns are really pulling one over on us! The end of the rainbow ....rainbows have no ends; they're really circles. We just see part of the arc of the rainbow circle. From a jet you can see the entire rainbow circle, it's called the glory. http://www.atoptics.co.uk/droplets/gloim21.htm

But it was discovered long before air travel....visible from high mountains in the sun, looking down into fog.....and it's even neater because instead of a plane silhouette at its center is a spooky specter (much too tall to be a leprechaun). The Specter of the Brocken: http://www.atoptics.co.uk/droplets/glory.htm

As all rain-weary Mainers know, rainbows appear only when the sun peeks out during rainstorms, and to see a rainbow the sun must be at your back. The primary rainbow appears 42 degrees away from the antisolar point (directly opposite the sun).

Here are some cool facts for your green beer party tonight:
Seawater rainbows are slightly smaller, about 41 degrees away from the antisolar point. Check out this cool photo for proof: http://www.atoptics.co.uk/rainbows/seabow.htm

Sometimes the luck of the Irish gives us double rainbows: http://www.atoptics.co.uk/rainbows/sec.htm

To understand how and why the colors are backwards and fainter, try this fun page, and be sure to mouse over the slider! http://www.atoptics.co.uk/rainbows/ord2form.htm

Here's some real leprechaun magic for you. Watch for it during spring rainstorms! Why is it always brighter inside the rainbow and darker outside? http://www.atoptics.co.uk/rainbows/adband.htm

And what are those alternating faint bands of green/purple/green/purple you sometimes see inside the rainbow? (They are super and numerous!): http://www.atoptics.co.uk/rainbows/supers.htm

These supernumerary bows are formed by overlapping light waves with both reinforcing and canceling waves:
http://www.atoptics.co.uk/rainbows/supform.htm Their colors always remind me of the "paint with water" coloring books I had as a kid. As you stroked a wet brush across the page only purplish pinks and greens would appear.

No two people ever see the same rainbow! Because your own personal rainbow forms from raindrops in a circle 42 degrees from your antisolar point: http://eo.ucar.edu/rainbows/rnbw4.gif Even someone standing right next to you will see light refracted from different raindrops.

And as for the legend of spurious leprechauns, well if you want to hide gold where no one will ever find it, the end of a rainbow's a perfect place! But the origin of this story comes from eastern Europe, not Ireland. There it's said that angels put the gold at the end of the rainbow and only a naked man could find it! So, you better be careful about just how much green beer you imbibe!

To learn more about rainbows check out the rainbows page of Les Cowley's wonderful Atmospheric Optics website: http://www.atoptics.co.uk/bows.htm
Also, browse through Robert Greenler's amazing book "Rainbows, Halos, and Glories". It's one of my favorites with lots of photos and diagrams explaining the mysteries of rainbows and other sky phenomena.

Happy St. Patrick's Day from
Roy G. Biv, that colorful 'ol Irishman
Head Leprechaun
The Dorr Museum of Natural History

March Comes in Like a Lion!

March roared in like a lion on the 1st with over 12 inches of blowing and drifting snow, but it's already becoming a little sheepish. On MDI snow in open areas is all but gone, persisting in forests and snow plow mountains. Recent storms mix snow, sleet and rain, teasing us with one last chance to preserve some snowflakes before winter's a memory. Some winter birds remain, like Northern Shrikes, Tree Sparrows, Evening Grosbeaks and a few Pine Grosbeaks. But winter's clearly on the wane.

March and April are always lions up in the night sky. Just "punch a hole in the bottom of the Big Dipper" and you'll arrive at Leo the Lion, his mane resembling a backwards question mark. An active solar wind is now hitting earth's magnetic field and strong auroras are forecast for tonight and tomorrow. Tonight looks clear, so keep watch!

Signs of spring are everywhere!
Common goldeneyes can be seen around Bar Island and sometimes one can catch them doing their head tossing courtship display.
Herring Gulls are also starting to "like" each other more.
Hooded Mergansers have begun to move to ponds with open patches of water,
While river otters are having fun cavorting on the ice at the Tarn.
Crows seem to have paired up. Eagles have been seen doing aerial courtship displays.
Best of all, to me....Redwing Blackbirds are starting to return to the thawing north!
And Grackles too! Their bronze blue plumage and striking golden eyes are a sight for my sore eyes.
Folks have seen Blue Jays and Cardinals nuptial feeding; i.e., gently passing a tidbit to their intended's beak.
Twigs of Red-osier Dogwood have become bright scarlet and

Red Maple buds look fire hydrant red.
Weeping willow branches have turned golden.

Warming days and frosty nights- can the maple sap run be far behind?

Enjoy this special season of late winter/early spring. There's much more than mud to look forward to! Keep your eyes and ears peeled for:
- the first waking woodchuck
- chipmunks at your feeder
- woodcocks will be back soon - listen for them peenting at twilight
- when will the first wood frogs quack this year?
- and place your bets on "Big Night" when scads of salamanders slither from the woods to chilly vernal pools to breed will occur this year. It happens during the first warm night rains and is a spectacle not to be missed!
- and check the marshes for the first flower of spring - skunk cabbage melting its way through the snow.

Thanks for your reports from the field and please keep them coming!
The Dorr Museum of Natural History