Embed Size (px)
Citation preview
January 2015 Volume 21 Number 7 Page 1
From the Prez….
It is December already and al-
most a new year! Stargazers have
had a good year. Our star parties
were not rained out and we will be
holding our 15Th
mirror making work-
shop in March 2015. We will have
another place to hold the mirror
making workshop in 2016 since we are
losing Mallard Lodge due to federal
grant restrictions. If anyone is
interested in helping to grind out
mirror blanks for the upcoming work-
shop, please contact Michael Lecuyer
at the meeting or email him at
Mostly likely we will start grinding
out the mirrors in the middle of
February for the mid- March work-
shop. This will be a great opportu-
nity to get to “get glasspushin’ fe-
ver” for anyone who is thinking
about making their own telescope
mirror and would like to know what
it’s about!
The Stargazers just recently
received a donation of an Ioptron
MC 6 F/12 Maksutov- Cassegrain
telescope. It has a 2 inch Ce-
lestron mirror diagonal and the ap-
paratus to set it up for astrophot-
ography. Only thing the scope is
lacking is a good tracking mount and
some eyepieces. The donation is
from Dan Boulet of Wilmington, DE.
He is not a member of our club but I
am working on it! Perhaps, we can
give him his first year membership!
For anyone thinking of buying a
telescope, use one of our Society’s
scopes! Use either the Ioptron
scope or our 10” Schmidt– Cas-
segrain. There is no charge; you
just need to be member! Contact
Don Surles or me about the use of
either scope. The 10“ has not been
used for 3 years! We also have a
solar telescope which can be bor-
rowed.
On Jan. 14, 2015, the Ap-
poquinimink School District will
hold Mission: Space which is a fam-
ily event that will allow families
to see moon rocks, handle space
suits, crawl through the STARlab
planetarium, and gaze at the night
sky through an array of high-
powered telescopes.
All of these activities have
been designed to complement Science
Standard 4: Earth in Space as it
pertains to study in Grades 4-5.
The Stargazers have been asked
to bring our telescopes to Ap-
poquinimink High School from 6 to
Star Gazer News
Newsletter of the Delmarva Stargazers www.delmarvastargazers.org
Upcoming Events: Meeting ! Jan 6
th 7 PM Smyrna Church
Observing ! Jan 16,17th
Dusk Eq. Cntr. or Blackbird
With the New Year,
It’s time to send in your dues !
See pg. 2 for instructions on pay-
ing your dues,
or better yet, come to the next
meeting on Jan 6th
January 2015 Volume 21 Number 7 Page 2
How to Join the Delmarva Stargazers: Anyone with an interest in any aspect of astronomy is welcome NAME_______________________________________________________________New_______Renew___________ ADDRESS_____________________________________________________________________________________ CITY, STATE & ZIP______________________________________________________________________________ E-MAIL ADDRESS (If any)_________________________________________________________________________ Do you need the newsletter snail mailed to you (Y/N)?___________________________________________________ Please attach a check for $15 made payable to Delmarva Stargazers and mail to Kathy Sheldon, 20985 Fleatown Rd, Lincoln, DE 19960. Call club President Lyle Jones at 302-382-3764 for more information.
8 pm for the event. The may
have over 200 attendees--- so we
need Stargazers and telescopes.
Retired NASA astronaut Dr. Don-
ald Thomas will be there and we are
invited to hear him speak before we
show the attendees the sky. Dr.
Thomas has logged over 1,040 hours
in space including missions on the
space shuttles Columbia and Discov-
ery, and a tour as program scientist
on the International Space Station.
If you have the time, we need
you and your scope. The event will
be at the Appoquinimink High School
on 1080 Bunker Hill Road in Middle-
town, DE. We should be there by
5:30 in order to set up and allow
the scopes to cool down. Contact
Jerry Truitt about attending
([email protected]). This is a
rain or shine event!
At our Holiday party we had 23
attending. There was plenty of the
food as usual. Jerry baked a great
ham and Don’s turkey was moist and
tasty. Karen Surles’ cranberry
was very good even though she said
that she put too much almond extract
in it. It was nice to see Kathy
Sheldon and Christen Graham up and
about but we missed Paul and Doreen
Riley. The white elephant was fun
as normal but not as much trading
went on. I guess that we had cleaned
out of basements and attics for our
prior White elephant exchanges and
we needed some more junk in order to
refill our allotment. Peter Graham
put one his old junkie eyepiece‘s
into last year exchange and got it
back this year!
Have a good holiday season and
see you at our next Delmarva Star-
gazer meeting on Jan. 6, 2015.
Check our website for the next
meeting’s agenda but I do know that
Jerry Truitt is doing his program on
weather observations. If anyone
is interested in doing the constel-
lation or object not the month,
please contact me. - Lyle
Molecular Cloud Barnard 68
Image Credit: FORS Team, 8.2-meter VLT Antu, ESO
Where did all the stars go? What used to be con-
sidered a hole in the sky is now known to astronomers as
a dark molecular cloud. Here, a high concentration of
dust and molecular gas absorb practically all the visible
light emitted from background stars. The eerily dark sur-
roundings help make the interiors of molecular clouds
some of the coldest and most isolated places in the uni-
verse. One of the most notable of these dark absorption
nebulae is a cloud toward the constellation Ophiuchus
known as Barnard 68, pictured above. That no stars are
visible in the center indicates that Barnard 68 is rela-
tively nearby, with measurements placing it about 500
light-years away and half a light-year across. It is not
known exactly how molecular clouds like Barnard 68 form,
but it is known that these clouds are themselves likely
places for new stars to form. In fact, Barnard 68 itself
has been found likely to collapse and form a new star
system. It is possible to look right through the cloud in
infrared light. From apod.nasa.gov
January 2015 Volume 21 Number 7 Page 3
Your 2014-2015 Officers Office Officer Phone email President Lyle Jones 302-382-3764 [email protected] President-elect Secretary Treasurer Kathy Sheldon 302-422-4695 [email protected] Past President Don Surles 302-653-9445 [email protected]
The FYI on Saturn
Saturn is the sixth planet from the
Sun and the second largest.
Saturn was the god of agriculture in
Roman mythology. Saturn is also the
father of Jupiter, the king of the
Roman gods.
Saturn is flattened at the poles, due
to a fast rotation on its axis.
Saturn has 62 known moons, fifty-
three have been named. Most of them
are small in size.
Names of some of Saturn’s moons: the
largest is Titan, discovered in 1655;
Tethys, Dione, Rhea, & Iapetus, dis-
covered from 1671 to 1672; Mimas &
Enceladus, discovered in 1789; and
Hyperion, discovered in 1848.
A year on Saturn is equal to 29.5
Earth Years.
Saturn is the only planet in our so-
lar system that is less dense that
water. This means that it would float
if there was a body of water large
enough to hold it.
A day on Saturn is equal to 10 hours
and 14 minutes in Earth days.
Diameter of Saturn is 74,500 miles.
Saturn’s maximum dis-
tance from the Sun is
938 million miles.
Saturn’s minimum dis-
tance from Earth is
746 million miles.
Saturn has fourteen
subdivisions of its
rings; the widest is
at 16,000 mi, the B
ring.
Saturn’s rings are
made primarily of
“water ice” mixed
with dust and other
chemicals.
Saturn’s fame has
been observed going
back to ancient times, the Babyloni-
ans, Romans, Greek, Hindus, and many
more ancient civilizations have taken
great interest in studying this
ringed planet.
If you weigh 100 lbs, your weight on
Saturn would be 108 lbs. (multiply
your actual weight by 1.08).
The temperature on Saturn by the
clouds is at -274° F.
Titan is Saturn's only moon that has
an atmosphere; it is also bigger than
Mercury.
The first astronomer to make note of
Saturn's rings was Galileo, although
his telescope was not powerful enough
and he thought that the rings were
actually satellites.
Saturn's rings are made of water,
ice, rocks, dust and other chemicals.
Pioneer 11 did the first flyby of the
planet in 1979. Since then, Voyager 1
was sent closer to Saturn and it took
much higher quality photographs.
In 2004 the Cassini-Huygens space
probe entered into orbit around Sat-
urn and also took vivid photos of
some of the planet's moons.
The day of the week, Saturday, is
named after Saturn.
Saturn at Equinox as seen by Cassini
January 2015 Volume 21 Number 7 Page 4
James Edward Keeler From Wikipedia, the free encyclopedia
J a m e s E d w a r d K e e l e r
(September 10, 1857 – August
12, 1900) was an American
astronomer.
Career and personal life
Keeler worked at Lick
Observatory beginning in
1888, but left after being
appointed director of the
University of Pittsburgh's
Allegheny Observatory in
1891. He returned to Lick
Observatory as its director
in 1898, but died not long
after in 1900. His ashes
were interred in a crypt at the base of the
31-inch Keeler Memorial telescope at the
Allegheny Observatory.
Along with George Hale, Keeler
founded and edited the Astrophysical Jour-
nal, which remains a major journal of as-
tronomy today.
His parents were William F. and Anna
(née Dutton) Keeler. He had married in 1891
and left a widow and two children.
Research
Keeler was the first to observe the
gap in Saturn's rings now known as the
Encke Gap, using the 36-inch refractor at
Lick Observatory on 7 January 1888. After
this feature had been named for Johann
Encke, who had observed a much broader
variation in the brightness of the A Ring,
Keeler's contributions were brought to
light. The second major gap in the A Ring,
discovered by Voyager, was named the Keeler
Gap in his honor.
In 1895, his spectroscopic study of
the rings of Saturn revealed that different
parts of the rings reflect light with dif-
ferent Doppler shifts, due to their differ-
ent rates of orbit around Saturn. This was
the first observational confirmation of the
theory of James Clerk Maxwell that the
rings are made up of countless small ob-
jects, each orbiting Saturn at its own
rate. These observations were made with a
spectrograph attached to the 13-inch Fitz-
Clark refracting telescope at Allegheny Ob-
servatory.
His observations with the Lick
Crossley telescope helped establish the im-
portance of large optical reflecting tele-
scopes, and expanded astronomers' under-
standing of nebulae. After his untimely
death, his colleagues at Lick Observatory
arranged for the publication of his photo-
graphs of nebulae and clusters in a special
volume of the Lick Observatory publica-
tions. Keeler discovered two asteroids,
one in 1899 and one in 1900, although the
second was lost and only recovered about
100 years later.
After the discovery of pulsars in
1967, optical images of the Crab Nebula
taken by Keeler in 1899 were used to deter-
mine the proper motion of the Crab Pulsar.
Keeler Gap
The Keeler Gap is a 42-kilometre-wide
gap in the A Ring, approximately 250 kilo-
metres from the ring's outer edge. The
small moon Daphnis, discovered 1 May 2005,
orbits within it, keeping it clear. The
moon induces waves in the edges of the gap.
Because the orbit of Daphnis is slightly
inclined to the ring plane, the waves have
a component that is perpendicular to the
ring plane, reaching a distance of 1.5 km
(0.93 mi) "above" the plane.
Honors and Legacy
Keeler was awarded the Henry Draper
Medal from the National Academy of Sciences
in 1899. In 1900 he was elected president
of the Astronomical Society of the Pacific.
In 1880, Allegheny Observatory direc-
tor Samuel Pierpont Langley, accompanied by
Keeler and others, went on a scientific ex-
pedition to the summit of Mount Whitney.
The purpose of the expedition was to study
how the Sun's radiation was selectively ab-
sorbed by the Earth's atmosphere, comparing
the results at high altitude with those
found at lower levels. As a result of the
expedition, a 14,240-ft. peak near Mount
Whitney was named the "Keeler Needle".
In addition to the Keeler gap in Sat-
urn's rings, craters on Mars and the Moon
are named in his honor, as is the asteroid
2261 Keeler.
The illuminated side of Saturn's rings with the major subdivisions labeled
January 2015 Volume 21 Number 7 Page 5
Eridanus From Wikipedia
Eridanus is represented as a river; its
name is the Ancient Greek name for the Po
River. It was one of the 48 constellations
listed by the 2nd century astronomer
Ptolemy, and it remains one of the 88 mod-
ern constellations. It is the sixth largest
of the modern constellations.
Stars
At its southern end is the magnitude
0.5 star Achernar, designated Alpha Eri-
dani. 144 light-years from Earth, it is a
blue-white hued main sequence star whose
traditional name means "the river's end".
Achernar is a very peculiar star because it
is one of the flattest stars known. Obser-
vations indicate that its radius is about
50% larger at the equator than at the
poles. This distortion occurs because the
star is spinning extremely rapidly.
There are several other noteworthy
stars in Eridanus, including some double
stars. Beta Eridani, traditionally called
Cursa, is a blue-white star of magnitude
2.8, 89 light-years from Earth. Its place
to the south of Orion's foot gives it its
name, which means "the footstool". Theta
Eridani, called Acamar, is a binary star
with blue-white components, distinguishable
in small amateur telescopes and 161 light-
years from Earth. The primary is of magni-
tude 3.2 and the secondary is of magnitude
4.3. 32 Eridani is a binary star 290 light-
years from Earth. The primary is a yellow-
hued star of magnitude 4.8 and the secon-
dary is a blue-green star of magnitude 6.1.
32 Eridani is divisible in small amateur
telescopes. 39 Eridani is a binary star di-
visible in small amateur telescopes, 206
light-years from Earth. The primary is an
orange-hued giant star of magnitude 4.9 and
the secondary is of magnitude 8. 40 Eridani
is a triple star system consisting of an
orange main-sequence star, a white dwarf,
and a red dwarf. The orange main-sequence
star is the primary of magnitude 4.4, and
the white secondary of magnitude 9.5 is the
most easily visible white dwarf. The red
dwarf, of magnitude 11, orbits the white
dwarf every 250 years. The 40 Eridani sys-
tem is 16 light-years from Earth. p Eridani
is a binary star with two orange compo-
nents, 27 light-years from Earth. The mag-
nitude 5.8 primary and 5.9 secondary have
an orbital period of 500 years.
Epsilon Eridani is a star with one
extrasolar planet similar to Jupiter. It is
an orange-hued main-sequence star of magni-
tude 3.7, 10.5 light-years from Earth. Its
one planet, with an approximate mass of one
Jupiter mass, has a period of 7 years.
Supervoid
The Eridanus Supervoid is a large su-
pervoid (an area of the universe devoid of
galaxies) discovered as of 2007. At a di-
ameter of about one billion light years it
is the second largest known void, super-
seded only by the Giant Void in Canes Ve-
natici. It was discovered by linking a
"cold spot" in the cosmic microwave back-
ground to an absence of radio galaxies in
data of the United States National Radio
Astronomy Observatory's Very Large Array
Sky Survey. There is some speculation that
the void may be due to quantum entanglement
between our universe and another.
Deep-sky objects
NGC 1535 is a small blue-gray plane-
tary nebula visible in small amateur tele-
scopes, with a disk visible in large ama-
teur instruments. 2000 light-years away, it
is of the 9th magnitude.
Eridanus contains the galaxies NGC
1232, NGC 1234 and NGC 1300, a grand design
barred spiral galaxy.
NGC 1300 is a face-on barred spiral
galaxy located 61 (plus or minus 8) million
light-years away. The center of the bar
shows an unusual structure: within the
overall spiral structure, a grand design
spiral that is 3,300 light-years in diame-
ter exists. Its spiral arms are tightly
wound.
Meteor showers
The Nu Eridanids, a recently discov-
ered meteor shower, radiate from the con-
stellation between August 30 and September
12 every year; the shower's parent body is
an unidentified Oort cloud object. Another
meteor shower in Eridanus is the Omicron
Eridanids, which peak between November 1
and 10.
History and mythology
According to one theory, the Greek
constellation takes its name from the Baby-
lonian constellation known as the Star of
Eridu (MUL.NUN.KI). Eridu was an ancient
city in the extreme south of Babylonia;
situated in the marshy regions it was held
sacred to the god Enki-Ea who ruled the
cosmic domain of the Abyss - a mythical
conception of the fresh-water reservoir be-
low the Earth's surface.
Eridanus is connected to the myth of
Phaëton, who took over the reins of his fa-
ther Helios' sky chariot (i.e., the Sun),
but didn't have the strength to control it
and so veered wildly in different direc-
tions, scorching both earth and heaven.
Zeus intervened by striking Phaëton dead
with a thunderbolt and casting him to
January 2015 Volume 21 Number 7 Page 6
earth. The constellation was supposed to be
the path Phaëton drove along; in later
times, it was considered a path of souls.
Since Eridanos was also a Greek name for
the Po (Latin Padus), in which the burning
body of Phaëton is said by Ovid to have ex-
tinguished, the mythic geography of the ce-
lestial and earthly Eridanus is complex.
Another association with Eridanus is
a series of rivers all around the world.
First conflated with the Nile River in
Egypt, the constellation was also identi-
fied with the Po River in Italy. The stars
of the modern constellation Fornax were
formerly a part of Eridanus.
Equivalents
The stars that correspond to Eridanus
are also depicted as a river in Indian as-
tronomy starting close to the head of Orion
just below Auriga. Eridanus is called Sro-
taswini in Sanskrit, srótas meaning the
course of a river or stream. Specifically,
it is depicted as the Ganges on the head of
Dakshinamoorthy or Nataraja, a Hindu incar-
nation of Shiva. Dakshinamoorthy himself is
represented by the constellation Orion.
The stars that correspond to Eridanus
cannot be fully seen from China. In Chinese
astronomy, the northern part is located
within the White Tiger of the West (西方白虎, Xī Fāng Bái Hǔ). The unseen southern part
was classified among the Southern Asterisms
(近南極星區, Jìnnánjíxīngōu) by Xu Guangqi,
based on knowledge of western star charts.
In popular culture
The game Halo: Reach takes place
within this constellation—the planet Reach
orbits Epsilon Eridani.
In some maps of the Star Trek uni-
verse the planet Vulcan is shown to be lo-
cated at 40 Eridani A.
Namesakes
USS Eridanus (AK-92) was a United
States Navy Crater class cargo ship named
after the constellation.
Eridan Ampora is a character known as
a troll from the interactive webcomic
called Homestuck named after the constella-
tion.
Cetus dips his paws into Eridanus in this plate from Urania's Mirror (1825).
January 2015 Volume 21 Number 7 Page 7
January 2015 Volume 21 Number 7 Page 8
Astrophotos from members and friends
Holiday Party !
