Planets, airplanes, birds

• Requires specialized knowledge to be useful – buyer beware!– Must be a true student of these with “local

knowledge” • Planets for navigation/steering• Airplane routes• Shipping lanes• Birds• Phosphorescence

Planets and navigation

• Typically can use three planets for navigation – Venus, Mars and Jupiter– The rest are too dim

• Useful websites– www.celnav.de/ragha.htm– www.ephemeris.com

• Motions wrt stars depends on both the earth’s orbit and planet’s orbit

• Hence the name: wanderers

Steering by the planets

• For latitude/longitude calculation, must know SHA and declination – from tables

• For steering, rough positions can be used one night after the next to hold a course

• Like the sun and stars, planets move westward by 1o per day

• Eastward motion against background of stars at varying rates

Motions of Planets

• Venus – always close to the sun, never further than 30o

– Morning star, evening star– Visible only up to two hours after sunset or before

sunrise.– Has been mistaken for a boat or a train– Moves east against fixed background of stars

• Jupiter – slow moving – roughly one sign of the zodiac per year

• Mars – in between

Current positions 19 Oct 08• Jupiter

– Decl: -22o 55’ , JH SHA: 73o 29’ W– Two weeks: -22o 39’, JH SHA: 71o W– Visible just after sunset

• Mars– Decl: -15o 0’ , JH SHA: 141o 47’– Two weeks: -18o , JH SHA: 130o W– Nearly hidden by sun, currently

• Venus– Decl: -21o 29’, JH SHA: 121o 9’ W– Two weeks: -25o, JH SHA: 100o W– Close to the sun, next to Antares (25S, 113W)

• Sun– Decl: -10o 19’, JH SHA: 155o 11’ W– Two weeks: -16o, JH SHA: 140o W

Jupiter Venus

MarsSun

Earth

Jupiter Mars

Venus

Snapshot of the relative positions of Jupiter, Mars, VenusEarth, Antares (distant) and the Sun now.

Antares

Tonight’s sky at 6 PM facing SW

SunMars

Venus

Jupiter

Antares

Ecliptic

Retrograde motion

As the earth overtakes a planet (superior retrograde) or a planet overtakesthe earth, the planet temporarily appears to be moving backwards againsta fixed background of stars.

Retrograde motionof Mars 1997

NB – Jupiter is justcoming out of retrograde

Airplanes

• Considerations for long distance flights– Typically follow great circle routes– Some changes in routing associated with jet

stream– Fly at altitudes of 30,000 to 40,000 ft– Speeds of roughly 500 mph– Visible from contrails, or from reflections

during day– Visible from nav/warning lights at night

Navigation and warning lights onaircraft.

New York to London

Chicago to Paris

San Francisco to Tokyo

Comments on routes• Large population in cities in N. Hemisphere

– Great circle routes tend toward high latitudes– Even over the North Pole– Avoid equatorial regions– Largely East-West directionality– Incoming flights from Europe from NE to SW– Outgoing flights more depressed – WSW to ENE

• New England flights to Europe– Outgoing flights 6 PM – 9 PM– Incoming flights 12 PM-4 PM

Landing/takeoffs/holding/N.A routes

• Aircraft frequently make multiple turns on approach to urban airports– Still, landing/takeoffs will be approximately

along lines radiating from local airports• Holding patterns – aircraft go on long oval

tracks• Many N-S routes on the east and west

coast• Many E-W routes in great plains, rockies.

Shipping lanes

• Like airplane routes, they often follow great-circle routes

• However, are constrained by coastlines, canals, etc.

• Pattern of shipping also constrained more by manufacturing, natural resources (e.g. oil) and population centers.

• Attracting help from a passing ship is very difficult!

Birds

• Homing birds fly away from islands during the day and fly home to their nests at night. – Ranges vary up to 100 miles out to sea

• Migratory birds like fly on certain pathways at certain times of the years

• Pelagic birds wander in the open ocean

Homing birds• Fly out to sea in search of food• At sunrise or sunset, they fly directly toward land• Can be used to “expand” the circle of landfinding

around an island – Polynesians• Examples

– Puffins– Boobies– Frigate birds– Pelicans

• Don’t ignore the possibility that single birds seen far out to sea are lost!

Expansion of circle of discovery of islands in Carolines

Migratory birds

• Can act as homing birds during the breeding season

• Fly long distances during migration season– Leach’s petrel– Jaegers– Plovers

Pelagic birds

• Wander around the ocean – for all practical purposes, aimlessly (some migratory and homing component during breeding season)– Albatross– Storm petrel– Noddies– Tropic birds

Sea birds of New England• Classic shore birds

– Gulls– Cormorants– Terns– Plovers

• Waterfowl– Common ducks– Eider ducks– Geese– Swans

Cormorant

Very common acrossthe globe.

Sits low in the water, dives for fish.

Must spend time in thesun to dry wings.

25 mile limit from land

Puffin

Mainly found in arctic andsub arctic locations.

Don’t migrate.

100 miles from land,will fly toward land at sunsetand sunrise

Eider duck

Migrate from arcticto Cape Cod duringDecember.

Winter over

Rarely seen more than10 miles out.

Herring gull

Very common

Seen far inland, followingrivers, etc.

Seen as far out as 50 milesto sea.

Will return to land at dusk

Mostly not migratory

Laughing gull

Males have black headduring breeding season(June-Sept).

Otherwise white.

During breeding, stayswithin 50 miles of land.

Non-breeding, called a “vagrant”.

Common terns

Sometimes calledSea swallows.

During summer breedingmonths, will be within50 miles of land.

Will migrate along coastSouth to Florida duringWinter.

Piping plover

Protected species

During breedingseason (Summer), stays within 10 milesof land.

Migrates south alongcoast during winter

Birds of the tropics

• Distinctly different species found in the tropical regions (Tropic of Cancer to Tropic of Capricorn)

• Many particular species related to those found further north– Noddies – related to terns– Cormorants– Pelicans

Frigate bird

Classic form of wings

Holds feet along narrowtail.

Seen up to 100 miles fromland, but always returns.

Boobies

Cross shape of wingsand beak are distinctive characteristics

Like frigate birds, these are one of thebetter homing speciesfor the navigator.

75 mile range from land

Pelicans

Big pouches underbills

Found less than 25 miles from land

Forked tails

Members ofthe tern family

Pelagic

Noddies

Tropicbird

Long, thin tail

Will breed nearland during wintermonths

Otherwise pelagic

Sooty shearwater

Hooked bill, pelagic AtlanticOcean bird.

Pelagic

Storm petrel

Small, shortbeak

Pelagic

Shows dartingmotions along water (thoughtto save energyin flight)

Albatross

Most have huge wingspan

Pelagic, roaming overlarge sections of the oceans

Other phenomena

• Phosphorescence - “underwater lightning”

Te Lapa, continued

What is it? Some form of bioluminescence.

It even has an anomaly designation – GLW11(Geophysical luminescence over Water 11