THE SOUTHWORTH PLANETARIUM
207-780-4249      www.usm.maine.edu/planet
70 Falmouth Street     Portland, Maine 04103
43.6667° N                   70.2667° W
Founded January 1970
Julian date:  2457638.16
            "Tourists are fleeing the state by the tens of thousands.  Now
that Maine has lost its summer population, the wait times in stores, in
traffic and at other public places will be greatly reduced.    Does this
mean that every September, Maine experiences rapid wait loss?"

*THE DAILY ASTRONOMER*
*Tuesday, September 6, 2016*
*The First Messier*

The year 2017 marks the 200th anniversary of the death of French astronomer
Charles Messier (1730-1817), an avid comet hunter who, ironically, is best
known for having compiled a catalog of celestial objects that resemble
comets, but aren't.   We still refer to this compilation as the "Messier
Catalog,"and the bodies listed within it are known as "Messier objects."
  During the 2016-2017 DA school year, we will individually examine all 110
Messier objects.    Sometimes, we'll devote an entire article to one of
them.  At other times, they'll appear on the "obverse side," of the DA,*
tucked away in a footnote or featured in "From the Catacombs of Infinite
Knowledge."      If we devoted a DA to each Messier (if you know the proper
pronunciation of his last name, you'll know that clause rhymes), we'd
relegate about half the school year to this catalog.    And, as you know,
we are trying to divert a Pacific Ocean's worth of information into our own
small burbling forest stream, so we have to prioritize.

The catalog's inception dates back to 1757 when the young French astronomer
Charles Messier was working as a draftsman under astronomer Joseph-Nicolas
Delisle.   Delisle hired Messier to record astronomical observations and to
search for Halley's Comet, which Halley had predicted would return to
Earth's skies in in 1758/1759.**     As Messier conducted his search, he
spotted a strange sight that appeared comet-like but didn't change it
position from night to night.    Although they don't swoop through the sky
like meteors, as often thought, comets do exhibit some motion over the
course of successive evenings.    The object Messier observed appeared
immovable relative to the background stars. It turned out that it wasn't a
comet at all, but a "nebula," a term applied to many celestial objects
which were also-cloud like in appearance. The word "nebula" derives from
the Latin word for "cloud"


*​French astronomer Charles Messier  (1730 - 1817). Although*
*he considered himself a comet hunter, he is principally*
*known for having compiled a catalog of celestial objects that*
*resemble comets.    (Painting by Nicolas Ansiaume) *


Finding an astronomical object that bore such a close resemblance to a
comet induced Messier to begin a catalog of these objects, for his benefit
and for others. He chose the body in the constellation Taurus as his first
entry and labeled it, appropriately enough, M1.     We know of M1 as the
Crab Nebula,a supernova remnant.      Messier didn't actually discover this
nebula, as it had previously been observed by German astronomer  John Bevis
(1695-1771).  (See "From the Catacombs of Infinite Knowledge.")

Throughout the subsequent years, Messier added many entries to his catalog.
  The second, M2, was a globular cluster in Aquarius which another
astronomer had also previously observed.    He did discover his third
listed object, (M3), a globular cluster in Canes Venatici.     He would go
onto add 110 objects altogether, 42 of which he discovered.

Today, we officially begin our year long tour of all these Messiers with
the very first of them all, M1: The Crab Nebula




​
As we can see from the above star chart, M1 is tucked away just north of
tau Tauri.    This nebula is all that remains of a massive star that went
supernova more than 7500 years ago.     As this star was located about 6500
light years from our solar system, the explosion was recorded in AD 1054.
The brilliant "star" was recorded by astronomers around the world, most
notably in the Americas and China.      The Crab Nebula -named by Lord
Rosse as the filaments are reminiscent of crab legs- is a heavy element
rich field of material 11 light years in diameter.      The material is
expanding at 1,500 kilometers per second, propelled by the ultra-powerful
supernova.



​*The Crab Nebula (M1): a supernova remnant in Taurus the Bull.    This
nebula was the first object that Charles Messier recorded in the Messier
catalog.   We are seeing a rapidly expanding cloud of material expelled by
a supernova.  It currently spans 11 light years and grows at 1,500
kilometers per second. Image: The Hubble Space Telescope.  *

Supernovae explosions serve two important roles in our galaxy.   They
create all the elements heavier than iron and disperse this metal rich
material through the galaxy.    Our own solar system formed after material
from a supernova mixed with a gas dust cloud.  This collision precipitated
a collapse and subsequent formation of myriad stars within a cluster. One
of these stars was the Sun, around which the planets formed.    By
observing the Crab Nebula,we might well be seeing the progenitor of
innumerable star clusters and associated planetary systems that will
populate the galaxy in the distant future.

Our cosmos shows itself to be quite adept at recycling.
*Another feature we're adding is the 'Daily Astronomer Obverse Side," or
DAOS:   a side b that we'll tack onto a DA now and then.      This DAOS
will contain the more information, short stories,quirky conversations,and
other extraneous material.    More information later.

**Edmond Halley realized that the comet which now bears his name made
repeated visits to the inner solar system throughout recorded human history
and, being a solar system object, was destined to return multiple times.
  Halley predicted this comet would appear again in 1759, following its
1682 apparition.     Halley died in 1742 and therefore didn't live to see
its return.     Messier was the first professional astronomer to see
Halley's Comet when it returned in January 1759.


_________________________________________________________
FROM THE CATACOMBS OF INFINITE KNOWLEDGE:
          *John Bevis:    Sighting a planetary rarity *

John Bevis,a German physician and astronomer, is not exactly a household
name, even among astronomers.  However, Bevis has done something that
nobody else has done.   He is the only human to have telescopically
observed a planet-planet occultation.  On May 28, 1737 he watched an
occultation of Mercury by Venus.  (An occultation is the direct passage of
one body in front of another.)      In January 1818, Venus occulted
Jupiter, but both bodies were too close to the Sun for safe viewing.    The
next planet-planet occultation will occur on November 22, 2065, when Venus
again occults Jupiter. (Mercury occults Neptune two years later.)    On
November 22, 2065, many people will most assuredly observe a planet-planet
occultation through telescopes.  Until that time, astronomer John Bevis
will be the only human to ever witness such an occultation through a
telescope.
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