Download 2006 04 LAAS Bulletin I.pub

LOS ANGELES ASTRONOMICAL SOCIETY
FOR SALE
Small Rich Field Reflector
This Bausch and Lomb telescope was donated by Tom Dorff, one of our previous
presidents. It has been refurbished and remounted as an equatorial. Our shop
director tested the mirror and discovered that it has a smooth parabolic figure. It
was used at the December 10th public star party where it gave very good images.
Primary Mirror Diameter – 130 mm (5.1”)
Focal Length – 715 mm (28.1”) f/5.5
Secondary Mirror – 1.3” elliptical
Finder – full aperture achromatic 6x30.
Focuser is a 1.25” helical with a removable extension tube about 2” long.
Mount is an older Jaegers light duty equatorial with 5/8” shafts which has been
upgraded with bronze bushings on both axes.
Drive is a modified Edmund with a 96 tooth bronze gear and a 1/15 RPM
synchronous motor..
Tripod legs are all aluminum (no plastic here).
The telescope comes equipped with a Meade 25 mm Modified Achromatic
eyepiece.
Note: There is a scratch in the coating of the primary that does not affect
performance. The mirror was inspected from the rear to verify that the scratch did
not extend to the glass.
Asking $175 (proceeds go to the LAAS).
Contact Dave Sovereign at (626) 794 – 0646 —
The LAAS Board of Directors would like you to take a brief look at the address
page of your bulletin. Near the bottom right is your dues date and a note if we have
your correct email address on file. In the event that you have "No Email Address
on File" or have a "Bad Email Address on File," we would like for you to send us
your correct email address to [email protected]. Email addresses are not shared with
anyone and are used by the Board to occasionally send out notices in regards to
LAAS activities.
Additionally, if it is convenient for you, the Board would like for you to elect to
receive an email notification for the presence of the bulletin online. The online
version of the bulletin usually comes out several days prior to you receiving the
print copy and saves the club a great deal of money in printing and mailing
costs.
Finally, take a look at your Dues Date. If it is coming up soon, please send our
Treasurer the renewal funds so that we may update our records accordingly. Thank
you for your time.
BULLETIN
volume 80, issue 4 April 2006
Stephan’s Quintet
By Tim Thompson
Stephan’s Quintet, a tight grouping of 5 galaxies, is one of the better known targets
for dedicated deep sky observers. It was originally discovered by Edouard Jean
Marie Stephan (1837-1923), in either 1876 or 1877, depending on who tells the tale,
using the Foucault 80-cm (31.5 inch) reflecting telescope at the Marseilles
Observatory in France. It can be found in the constellation of Pegasus, at a right
ascension 22h 35m 57s, and declination +33d 57m 36s.
(Continued on page 4)
Inside this issue
Stephan’s Quintet (Tim Thompson) ······································ 1,4-7
Contact Information ······························································ 2
Editor’s Message (David Nakamoto) ··································· 2
Outreach Program (Don DeGregori) ···································· 2
This Month In History (Mary Brown) ·································· 3
The Art of Observing (David Nakamoto) ···························· 8-11
Two Mirror Blanks ······························································· 12
Desert Sunset Star Party························································ 12
“Shake It” flashlight ····························································· 13
Monterey Park Observatory Map ········································· 13
Loaner Corner (David Sovereign) ········································ 14
Events Calendar ··································································· 15
Membership Information ····················································· 15
Telescope for Sale (David Sovereign) ·································· 16
Message From the Board (Peter DeHoff) ····························· 16
Notes, corrections, questions, ideas, articles? All are welcome at:
[email protected].
The LAAS Board of Directors. —
Page 16
LAAS Bulletin
Page 1
LAAS Bulletin
OUR 80th YEAR OF
ASTRONOMY IN LOS ANGELES
Los Angeles Astronomical Society
Griffith Observatory Satellite
4800 Western Heritage Way
Los Angeles, CA 90027
(213) 673-7355
Change of Address, Membership:
Penny Hunter, LAAS Secretary
(323) 664-9781
LAAS Officers:
President . . . . . . . . . . . . David Sovereign
(626) 794-0646
Vice President . . . . . . . . . . . Mary Brown
[email protected]
Treasurer . . . . . . . . . . . . . Darrell Dooley
[email protected]
Secretary . . . . . . . . . . . . . . Wendy Brown
[email protected]
Recording Secretary . . . . . PJ Goldfinger
(323) 953-6869
Volunteers:
Library . . . . . . . . . . . . . . . . . Mary Brown
[email protected]
Outreach . . . . . . . . . . . . . Don DeGregori
[email protected]
[email protected]
Loaner Scopes . . . . . . . . Dave Sovereign
(626) 794-0646
Messier Program . . . . . . . . Norm Vargas
(626) 288-4397
New Members . . . . . . . . . . . . . . . . . TBA
Speakers Bureau . . . . . . . Tim Thompson
[email protected]
Youth Liaison . . . . . . . . . . . . . . . . . .TBD
LAAS Bulletin Editor . . David Nakamoto
[email protected]
Bulletin Printers and Web Site Managers
Peter De Hoff & Minghua Nie
[email protected]
Contributing Editors . . . . . . .Mary Brown
[email protected]
Don DeGregori
[email protected]
David Sovereign
(626) 794-0646
I
Editor ’s
Message
’ve received the news as this bulletin
was going to press that our
President, David Sovereign, was in
the hospital for a week. I’d like to wish
Dave a quick recovery and hope he can
return to his daily routine soon. Due to
this there will be no President’s
Message this month.
This month sees three telescopes for
sale and two mirror blanks being
offered! Spring cleaning?
Please send all written correspondence,
other than bulletin material, to:
LAAS
4800 Western Heritage Way
Los Angeles, CA 90027.
There will be one more change of
address when Griffith Observatory reopens.
For those wishing to submit material
for the bulletin, the deadline is the 10th
of each month to provide the necessary
the time to prepare all material into the
bulletin and get it to our printers in
time. —
David Nakamoto
The Outreach Program
LAAS Outreach participated in a Star
Party at Irwin Elementary School in La
Puente on Feb 23rd.
It was very successful and the kids,
parents, and teachers appreciated us
c o mi n g o u t . It was h e l d o n
the school grounds. Paul Wicker
transformed again to Galileo Guy and
(Continued on page 3)
Page 2
LAAS Bulletin
EVENTS CALENDAR
Date
Event
Location
Apr 1st (Sat)
Public Star Party
Griffith Observatory Satellite
Moon and Saturn
Apr 10th (Mon)
General Meeting
The speaker is scheduled to be Amanda
Mainzer of JPL
The topic is Brown Dwarfs.
Apr 29th (Sat)
Dark Sky Night
Lockwood Valley
May 6th (Sat)
Public Star Party
Griffith Observatory Satellite
Moon and Saturn
May 8th (Mon)
General Meeting
The speaker is To Be Determined.
May 27th (Sat)
Dark Sky Night
Lockwood Valley
A reminder ― The board meeting is held on the Wednesday night prior to the
general meeting, at Garvey Ranch Park. It starts at 8:00 pm
The Monday general meetings starts at 7:30 pm
LAAS Home Page: http://www.laas.org
LAAS Bulletin Online: http://www.laas.org/bulletin.html
Membership Annual Dues:
Youth
$ 20.00
Regular (18-65)
$ 35.00
Senior Citizen (65 and up)
$ 20.00
Senior Family
$ 30.00
Family
$ 50.00
Group or Club
$ 50.00
Life
$ 500.00
Additional fees:
Charter Star member
$ 30.00
Star member, with pad
$ 70.00
Star member, no pad
$ 60.00
(Membership due date is indicated on the mailing label)
Vol 80, issue 4
HANDY PHONE
LIST
LAAS Answering Machine ...... (213) 673-7355
Griffith Observatory
Program .............................. (323) 664-1191
Offices ................................. (323) 664-1181
Sky Report .......................... (323) 663-8171
Lockwood Site ........................ (661) 245-2106
(not answered, arrange time with caller.
Outgoing calls – collect or calling card)
Mt. Wilson Institute ................. (626) 793-3100
Page 15
LOANER CORNER
Saturn is just past opposition and is in a good
position for viewing in the evening. Orion and
Taurus have regained control of the winter nights
and spring is only two months away. Check out one
of the LAAS loaner telescopes and take advantage
of the clear winter
nights.
LAAS-2
LAAS-1 - 4.5” f/8
Celestron reflector
on a solid Polaris
equatorial mount. It
comes equipped with
a Kellner eyepiece, two Orthoscopics, and a
collimation tool. These two 4.5” reflectors are
good telescopes for beginners to learn with since
they are both small enough to be easily carried
and set up, but with enough aperture to provide
good views.
The seeing was pretty good, thanks to most of the security lights turned off.
Seeing Saturn produced many Wow's !. Outreach participants were Tom Drouet,
Herb Kraus, Regie Flores, Paul Wicker, and Don DeGregori. —
Don DeGregori
THIS MONTH IN HISTORY
April 8,1947, the largest sunspot group recorded was observed on the sun’s
southern hemisphere. Its size was estimated at 7 billion square miles, or 6100
millionths of the Sun’s visible surface. Large sunspots usually measure from 300
to 500 millionths and the Earth surface area is only 169 millionths of the visible
sun. The sunspot lasted several solar rotations.
April 14, 1611 the word telescope was used for the first time by Prince Federico
Cesi at a banquet held by the Pioneer Scientific Society to honor Galileo who
showed the guest Jupiter its moons and other celestial objects. Telescopio in
Italian is formed from two Greek words tele-far and scopeo-see.
LAAS-2 - 4.5” f/8 Tasco reflector on a motorized
Edmund equatorial mount. This telescope has
been upgraded with 1.25” accessories, a 6x30 finder, and very solid wooden legs.
It comes fully equipped with a set of three Kellner eyepieces and a collimation
tool.
LAAS-4 – 6” f/5 reflector by Telescopics on a low Dobsonian mount. It is
equipped with a set of three Orthoscopic eyepieces.
LAAS-8 – 80 mm f/11.4 Selsi refractor on an
equatorial mount. It is equipped with two
Plossl eyepieces and an Orthoscopic.
For further information concerning these
loaner telescopes call: David Sovereign at
(626) 794-0646. —
April 18, 2006 marks the 100th anniversary of the San Francisco Earthquake. At
5:12 am local time a foreshock occurred which was widely felt throughout the
San Francisco Bay area 20 seconds later the main shock occurred which lasted
45 to 60 seconds. People felt the quake from southern Oregon to Los Angeles
and inland as for as central Nevada. The intensity measured on the Modified
Mercalli Scale was given as VII TO IX and the magnitude numbers range from
7.7 to 8.3 San Francisco was not the only city, which had major damage from the
earthquake the list includes San Jose, Santa Rosa and other smaller cities. Glady
Hansen and Emmet Condor, estimate that over 3,000 deaths were caused directly
or indirectly by the catastrophe. This is from a population of 400,000 in San
Francisco.
A Portion of Emma m. Burke eyewitness account:
“The earthquake grew constantly worse, the noise deafening; the crash of dishes,
falling pictures, the rattle of the flat tin roof, bookcases being overturned the
piano hurled across the parlor, the groaning and straining of the building itself,
broken glass and falling plaster, made such a roar that no one noise could be
distinguished.”
Part of Dr. George Blumer Eyewitness account:
When the water gave out it was decided to check the spread of the fire in certain
districts by blowing up houses.
Some more facts: The number of people left homeless was 225,000. The number
of building destroyed was over 28,000. Estimated property damage 400,000,000
in 1906 money. —
Mary Brown
LAAS-4
Page 14
was hit with his presentation.
LAAS Bulletin
Vol 80, issue 4
Page 3
“Shake-It”
The 5 galaxies in the group are NGC-7317, NGC-7318A, NGC-7318B, NGC7319 & NGC-7320. As it turns out, NGC-7320 is a chance aligned foreground
object, only about 35,000,000 light years away. But the other 4 galaxies, which
are about 270,000,000 light years in the background, are a tightly clustered,
strongly interacting group. And they are not alone, either. Off to the southeast
from the quintet is the small spiral galaxy NGC-7320C. A few hundred million
years ago, NGC-7320C plowed through the 4 clustered galaxies from behind (as
seen from Earth), and pulled out the large tidal tail that can be seen extending
from NGC-7319.
flashlight requires no batteries. It uses
Faraday’s Principle of Magnetic
Induction and a bright LED to produce
light without batteries. A 30-second
shaking can recharge the capacitor to
produce enough energy to provide about
5 minutes of light.
Today, NGC-7318B is doing the colliding, and as a result of that collision, a
colossal shock wave, 130,000 light years long, is careening through the cluster.
That shock wave was seen by the Chandra X-ray telescope in July 2000. In
December 2005, the Spitzer Science Center released an image of the same shock
wave, taken by the infrared Spitzer Space Telescope. The Chandra image traces
extremely hot, ionized gas. The Spitzer image traces extremely hot molecular
hydrogen. The Chandra image is not surprising, hot ionized gas is expected at a
shock. But the Spitzer image is a surprise, because the presence of so much
molecular hydrogen is unexpected.
Larry Guerra has also added a red filter behind the
front lens and shield around the LED to make the
flashlight night observing compatible. The flashlight
come in two version, one is decorated with LAAS club
name or Logo, one is undecorated. It is sold at $12 –
profits go to the LAAS– (compare to $13-15, plus
shipping online or $19 at Big 5 Sporting store, which
comes without red filter, shield, or LAAS logo).
We all know that the universe is dominated by hydrogen gas. But most of it is
atomic hydrogen, and much of that is ionized. Atomic hydrogen cannot normally
form molecular hydrogen as a gas, there has to be a surface of some kind for the
reaction to take place on. So, atomic hydrogen usually forms molecular hydrogen
in the presence of dust grains, where the surface of the grain acts as a catalyst to
make the chemistry work. But in the case of Stephan’s Quintet, that is not the
case. We speculate that the molecular hydrogen is formed in the wake of the
shock wave, where the gas is rapidly cooling, much more rapidly than under any
normal circumstances. It may be that the Spitzer Space Telescope has found a
new way to make molecular hydrogen, and has done it in one of our favorite
objects.
Orders can be placed by sending a check or money order in the amount of $12.00 +
$2.00 S&H paid in the order of
Rachel Llamas at P.O BOX 1320 SOUTH GATE, CA 90280
Blvd
Gabriel
Garvey Ave
Orange
Ave
LAAS Bulletin
San
10 Freeway
N
Page 4
Del Mar Ave
Valley Blvd
New
Ave
Garfield Ave
Alhambra Ave
(The place to build your telescope)
Atlantic Blvd
Stephan’s Quintet, also known as Hickson Compact Group 92, is the seen of a
great cosmic collision, which can only be guessed at in visible images, but is
revealed in its full glory in X-rays & infrared. It is the closest of many such
groups, and the easiest to study. The focus of many research programs by
professional astronomers, and also a favorite of amateurs, Stephan’s Quintet is
one of the more interesting deep sky objects to look for in your dark sky
observing. —
Map to Monterey Park Observatory
Vol 80, issue 4
Graves Ave
Garvey Ranch
Park Observatory
Page 13
Two Mirrors Need Happy Homes
Jack Warford is trying to find the gentleman who was interested in a 4-inch
mirror blank and tool he acquired from one of the raffles at a general meeting.
He remembers this gentleman was about 5' 6" with a moustache. He would be
happy to give the mirror and blank to him.
He also has a partially ground 6" mirror. It has a small chip on one edge but it
would have no effect on the final result. It may be a little rich field, since it
seems to have a focal length of about three feet.
Please contact Jack directly at [email protected]. —
4th Annual Desert Sunset Star Party
This news is from Pat and Arleen Heimann.
The 4th annual Desert Sunset Star Party will be held April 26-30, 2006. Please
check details at our website
http://www.chartmarker.com/sunset.htm
Registration is now open. Caballo Loco RV Ranch gives us a special camping
rate for this group event. There is no star party fee this year but we will sell door
prize tickets. The residents of Caballo Loco will also be serving breakfast ($3)
and dinner ($5) on Saturday. We are located between Kitt Peak Observatory and
Whipple Observatory, both excellent day trips. —
(Above) Fig 1: Stephan’s Quintet, in an image released by the European Space
Agency. The HST WFPC2 image measures 3.7 x 2.5 arc minutes.
For Sale — 120-mm Refractor
120-mm aperture f/5 Orion (Syntha) two-element objective refractor with black
finish, German equatorial mount with dual speed RA motor drive, 8x50 finder
with illuminated reticle (illuminator included), 25-mm eyepiece and star
diagonal, carrying bag for refractor. Asking $630. Requires pickup at either
seller’s home or LAAS general meeting or Wednesday nights at Garvey Ranch
park (will not ship).
(Opposite page) Fig 2:
Stephan’s Quintet, with a
Chandra X-ray image
superimposed on an
optical image. The bright
blue X-ray emitting
region shows the shock,
and coincides with the
green patch in the Spitzer
image, tracing molecular
hydrogen.
If interested, call David Nakamoto at (626) 905 - 2704 or write to
[email protected]. —
FOR SALE — 10-inch Reflector
10" f/5 Cave Astrola reflector w eyepieces and rotating rings $500.
Contact William Llano at 714 255 0845 or [email protected] —
Page 12
LAAS Bulletin
Vol 80, issue 4
Page 5
avoiding direct lighting that shines on your and your equipment, avoiding
looking through or around glows in the sky caused by earth lighting, et al. The
fragment labeled C is the brightest one so far, and might be visible to the unaided
eye when the comet comes close to the earth. Fragment E is significantly fainter
but should be visible in moderately sized telescopes. —
(Above) Fig 3: Stephan’s Quintet, as seen by the
infrared Spitzer Space Telescope. The image is a
composite of 8-micron IR from Spitzer (green), along
with visible & H-alpha from the Calar Alto
Observatory in Spain.
(Left) Fig 4: Edouard Jean-Marie Stephan (31 Aug
1837 – 31 Dec 1923), discoverer of Stephan’s Quintet,
director of the Marseilles Observatory, co-discoverer of
comet 38P/Stephan-Oterma. He even tried to measure
stellar diameters by optical interferometry in the late
1800’s.
Page 6
LAAS Bulletin
The Double Cluster, located between Cassiopeia and Perseus. Image taken by
Rick Wiggins from Lockwood Valley on Nov 29th 2005 using an Astrophysics
155 EDF with a field flattener and an SBIG STL11k.
Vol 80, issue 4
Page 11
sun. At the time, it was an 11th mag speck on their photographic plates, but in a
few months it had come within 5.7 million miles of the earth, then after passing
the earth it approached the sun just within earth’s orbit before roaming out just
beyond Jupiter’s orbit.
Fig 5: The Foucault 80 cm
(31.5 inch) reflecting
telescope at the Marseilles
Observatory. Foucault
invented the knife-edge test in
making this mirror, which was
the first large silver on glass
telescope mirror. This
telescope saw the first
astronomical application of
the Fizeau optical
interferometer, and was used
by Fabry & Perot in the
invention of their multiple
reflection interferometer.
The comet was determined to have an orbit typical of many that are in the socalled Jupiter Family. The chart on the previous page shows the orbit along with
earth’s and Jupiter’s. These comets has one thing on common; their aphelions or
farthest point in their orbits from the Sun are within 1.0 AU of Jupiter’s orbit.
This means that, from time to time, if the comet and Jupiter happen to be in the
sections of their orbits near one another, that Jupiter can significantly affect the
comet and change its orbit. You can see this on the figure here, showing a view
looking down on the Solar System, with the orbits of earth, Jupiter, and SW-3
shown. This gravitational alteration of its orbit explained what happened to the
comet after its discovery in 1930. For FIFTY YEARS no one saw the comet,
although the orbit has a period of approximately 5.34 years. During the next
apparition it was not favorably placed for observations. The reason for this is
that 0.34 years tagged onto the comets orbital period. This mean that, on the
average, only one out of three apparitions are favorably placed to view from
earth. Then in 1953 the comet passed within 0.9 AU of Jupiter. This changed
the orbit and altered the sky positions and the times when the comet would be
visible. Then in 1965 the comet passed even closer to Jupiter, to within 0.25 AU.
This further changed its orbit significantly. Then in 1979 a comet was
discovered by an observatory in Perth, Australia. After the orbit was determined,
it was found that this comet and Schwassmann-Wachmann 3 were one and the
same. Along with determining that the two comets were the same, the
International Astronomical Union determined why the orbit was significantly
different, explaining the 50 year gap in observations.
The comet was missed in 1984 when once again the comet’s position was not
favorable for observations. It was sighted again in 1989 and 1994. Then at the
end of the 1994 apparition, the nucleus split apart into at least 9 fragments,
labeled A through I. Although the 2000 apparition was not too favorable for
amateurs the comet was sighted again. Three of the fragments were imaged by
amateurs. This was the situation astronomers faced when predicting the 2006
apparition.
As of press time, two of the fragments seem to be behaving in such a way that the
predicted light curves show both fragments will become bright enough to be seen
by amateur telescopes, and one might reach unaided eye visibility.
But observing comets is never easy. Basically, they’re no different than most
spiral galaxies, and for many of the same reasons. In spiral galaxies the core is
usually brighter and more easily seen than the arms, and often appears like a
fuzzy star. In comets the nucleus is usually brighter than the coma or tail, and
also appears like a fuzzy star. The usual precautions need to be taken ―
(Continued on page 11)
Page 10
LAAS Bulletin
Chicago’s famed Adler Planetarium and Astronomy Museum. Taken by David
Pinsky.
Vol 80, issue 4
Page 7
The Art of Observing
Comet Schwassmann-Wachmann 3
By David Nakamoto
April 2006
During the month of April we’re treated to the start of periodic comet
Schwassmann-Wachmann 3’s passage by the earth. As I explained in my
February talk, SW-3 has undergone a breakup of its nucleus during its 1996
apparition, and while one of the returning fragments looks like it’s going to
achieve close to unaided eye visibility or brighter, after this apparition the comet
will very likely be invisible to amateurs on earth. But as with anything
concerning comets, nothing is certain. What is certain is that we won’t get a
good look at this comet until ten to fifteen years from now.
means it should be fairly bright. While it is true that the new nuclei produced by
the breakup in 1996 are not as large as the original, fresh surfaces appear to be
still active sites where gas and dust are being spewed out. This is also the closest
the comet has come since its discovery in 1930, passing by at around 6.7 million
miles as opposed to 5.7 million in 1930. After this, the next couple of apparitions
the comet will be unfavorably placed for observations from earth.
The history of this comet begins in 1930, then Arnold Schwassmann (shown on
the proceeding page on the left) and Arno Wachmann (shown on the right with
Bernhard Schmitt to his right) of the Heidelberg observatory were conducting a
photographic search for asteroids. In the course of this survey they found at least
three comets, which now bear their names. The one discovered in 1930 and
approaching earth now is the 3rd such comet discovery for the pair, hence
Schwassmann-Wachmann 3, or SW-3 for short. It is also known as comet 73P
for the 73rd periodic comet recognized.
They found this interloper before it approached closely to both the earth and the
(Continued on page 10)
At this point, I have to put in a retraction. I thought that in 2025 the comet will
undergo a close interaction with Jupiter that will change its orbit and cause it to
become unobservable for amateurs. However, further research has shown that
this is not the case. It appears SW-3 will undergo a couple of relatively close
encounters with Jupiter as I said, but the result of this is to make the orbital
period oscillate between roughly 5.3 and 5.7 years, with attendant changes in the
orbit, but it should be visible to amateurs during some of its passages through
perihelion.
SW-3 should produce a good show. The comet is noted for being dusty, which
(Continued on page 9)
Arnold Schwassmann
Page 8
Arno Wachmann, with Bernhard Schmidt on the
left.
LAAS Bulletin
Vol 80, issue 4
Page 9
The Art of Observing
Comet Schwassmann-Wachmann 3
By David Nakamoto
April 2006
During the month of April we’re treated to the start of periodic comet
Schwassmann-Wachmann 3’s passage by the earth. As I explained in my
February talk, SW-3 has undergone a breakup of its nucleus during its 1996
apparition, and while one of the returning fragments looks like it’s going to
achieve close to unaided eye visibility or brighter, after this apparition the comet
will very likely be invisible to amateurs on earth. But as with anything
concerning comets, nothing is certain. What is certain is that we won’t get a
good look at this comet until ten to fifteen years from now.
means it should be fairly bright. While it is true that the new nuclei produced by
the breakup in 1996 are not as large as the original, fresh surfaces appear to be
still active sites where gas and dust are being spewed out. This is also the closest
the comet has come since its discovery in 1930, passing by at around 6.7 million
miles as opposed to 5.7 million in 1930. After this, the next couple of apparitions
the comet will be unfavorably placed for observations from earth.
The history of this comet begins in 1930, then Arnold Schwassmann (shown on
the proceeding page on the left) and Arno Wachmann (shown on the right with
Bernhard Schmitt to his right) of the Heidelberg observatory were conducting a
photographic search for asteroids. In the course of this survey they found at least
three comets, which now bear their names. The one discovered in 1930 and
approaching earth now is the 3rd such comet discovery for the pair, hence
Schwassmann-Wachmann 3, or SW-3 for short. It is also known as comet 73P
for the 73rd periodic comet recognized.
They found this interloper before it approached closely to both the earth and the
(Continued on page 10)
At this point, I have to put in a retraction. I thought that in 2025 the comet will
undergo a close interaction with Jupiter that will change its orbit and cause it to
become unobservable for amateurs. However, further research has shown that
this is not the case. It appears SW-3 will undergo a couple of relatively close
encounters with Jupiter as I said, but the result of this is to make the orbital
period oscillate between roughly 5.3 and 5.7 years, with attendant changes in the
orbit, but it should be visible to amateurs during some of its passages through
perihelion.
SW-3 should produce a good show. The comet is noted for being dusty, which
(Continued on page 9)
Arnold Schwassmann
Page 8
Arno Wachmann, with Bernhard Schmidt on the
left.
LAAS Bulletin
Vol 80, issue 4
Page 9
sun. At the time, it was an 11th mag speck on their photographic plates, but in a
few months it had come within 5.7 million miles of the earth, then after passing
the earth it approached the sun just within earth’s orbit before roaming out just
beyond Jupiter’s orbit.
Fig 5: The Foucault 80 cm
(31.5 inch) reflecting
telescope at the Marseilles
Observatory. Foucault
invented the knife-edge test in
making this mirror, which was
the first large silver on glass
telescope mirror. This
telescope saw the first
astronomical application of
the Fizeau optical
interferometer, and was used
by Fabry & Perot in the
invention of their multiple
reflection interferometer.
The comet was determined to have an orbit typical of many that are in the socalled Jupiter Family. The chart on the previous page shows the orbit along with
earth’s and Jupiter’s. These comets has one thing on common; their aphelions or
farthest point in their orbits from the Sun are within 1.0 AU of Jupiter’s orbit.
This means that, from time to time, if the comet and Jupiter happen to be in the
sections of their orbits near one another, that Jupiter can significantly affect the
comet and change its orbit. You can see this on the figure here, showing a view
looking down on the Solar System, with the orbits of earth, Jupiter, and SW-3
shown. This gravitational alteration of its orbit explained what happened to the
comet after its discovery in 1930. For FIFTY YEARS no one saw the comet,
although the orbit has a period of approximately 5.34 years. During the next
apparition it was not favorably placed for observations. The reason for this is
that 0.34 years tagged onto the comets orbital period. This mean that, on the
average, only one out of three apparitions are favorably placed to view from
earth. Then in 1953 the comet passed within 0.9 AU of Jupiter. This changed
the orbit and altered the sky positions and the times when the comet would be
visible. Then in 1965 the comet passed even closer to Jupiter, to within 0.25 AU.
This further changed its orbit significantly. Then in 1979 a comet was
discovered by an observatory in Perth, Australia. After the orbit was determined,
it was found that this comet and Schwassmann-Wachmann 3 were one and the
same. Along with determining that the two comets were the same, the
International Astronomical Union determined why the orbit was significantly
different, explaining the 50 year gap in observations.
The comet was missed in 1984 when once again the comet’s position was not
favorable for observations. It was sighted again in 1989 and 1994. Then at the
end of the 1994 apparition, the nucleus split apart into at least 9 fragments,
labeled A through I. Although the 2000 apparition was not too favorable for
amateurs the comet was sighted again. Three of the fragments were imaged by
amateurs. This was the situation astronomers faced when predicting the 2006
apparition.
As of press time, two of the fragments seem to be behaving in such a way that the
predicted light curves show both fragments will become bright enough to be seen
by amateur telescopes, and one might reach unaided eye visibility.
But observing comets is never easy. Basically, they’re no different than most
spiral galaxies, and for many of the same reasons. In spiral galaxies the core is
usually brighter and more easily seen than the arms, and often appears like a
fuzzy star. In comets the nucleus is usually brighter than the coma or tail, and
also appears like a fuzzy star. The usual precautions need to be taken ―
(Continued on page 11)
Page 10
LAAS Bulletin
Chicago’s famed Adler Planetarium and Astronomy Museum. Taken by David
Pinsky.
Vol 80, issue 4
Page 7
avoiding direct lighting that shines on your and your equipment, avoiding
looking through or around glows in the sky caused by earth lighting, et al. The
fragment labeled C is the brightest one so far, and might be visible to the unaided
eye when the comet comes close to the earth. Fragment E is significantly fainter
but should be visible in moderately sized telescopes. —
(Above) Fig 3: Stephan’s Quintet, as seen by the
infrared Spitzer Space Telescope. The image is a
composite of 8-micron IR from Spitzer (green), along
with visible & H-alpha from the Calar Alto
Observatory in Spain.
(Left) Fig 4: Edouard Jean-Marie Stephan (31 Aug
1837 – 31 Dec 1923), discoverer of Stephan’s Quintet,
director of the Marseilles Observatory, co-discoverer of
comet 38P/Stephan-Oterma. He even tried to measure
stellar diameters by optical interferometry in the late
1800’s.
Page 6
LAAS Bulletin
The Double Cluster, located between Cassiopeia and Perseus. Image taken by
Rick Wiggins from Lockwood Valley on Nov 29th 2005 using an Astrophysics
155 EDF with a field flattener and an SBIG STL11k.
Vol 80, issue 4
Page 11
Two Mirrors Need Happy Homes
Jack Warford is trying to find the gentleman who was interested in a 4-inch
mirror blank and tool he acquired from one of the raffles at a general meeting.
He remembers this gentleman was about 5' 6" with a moustache. He would be
happy to give the mirror and blank to him.
He also has a partially ground 6" mirror. It has a small chip on one edge but it
would have no effect on the final result. It may be a little rich field, since it
seems to have a focal length of about three feet.
Please contact Jack directly at [email protected]. —
4th Annual Desert Sunset Star Party
This news is from Pat and Arleen Heimann.
The 4th annual Desert Sunset Star Party will be held April 26-30, 2006. Please
check details at our website
http://www.chartmarker.com/sunset.htm
Registration is now open. Caballo Loco RV Ranch gives us a special camping
rate for this group event. There is no star party fee this year but we will sell door
prize tickets. The residents of Caballo Loco will also be serving breakfast ($3)
and dinner ($5) on Saturday. We are located between Kitt Peak Observatory and
Whipple Observatory, both excellent day trips. —
(Above) Fig 1: Stephan’s Quintet, in an image released by the European Space
Agency. The HST WFPC2 image measures 3.7 x 2.5 arc minutes.
For Sale — 120-mm Refractor
120-mm aperture f/5 Orion (Syntha) two-element objective refractor with black
finish, German equatorial mount with dual speed RA motor drive, 8x50 finder
with illuminated reticle (illuminator included), 25-mm eyepiece and star
diagonal, carrying bag for refractor. Asking $630. Requires pickup at either
seller’s home or LAAS general meeting or Wednesday nights at Garvey Ranch
park (will not ship).
(Opposite page) Fig 2:
Stephan’s Quintet, with a
Chandra X-ray image
superimposed on an
optical image. The bright
blue X-ray emitting
region shows the shock,
and coincides with the
green patch in the Spitzer
image, tracing molecular
hydrogen.
If interested, call David Nakamoto at (626) 905 - 2704 or write to
[email protected]. —
FOR SALE — 10-inch Reflector
10" f/5 Cave Astrola reflector w eyepieces and rotating rings $500.
Contact William Llano at 714 255 0845 or [email protected] —
Page 12
LAAS Bulletin
Vol 80, issue 4
Page 5
“Shake-It”
The 5 galaxies in the group are NGC-7317, NGC-7318A, NGC-7318B, NGC7319 & NGC-7320. As it turns out, NGC-7320 is a chance aligned foreground
object, only about 35,000,000 light years away. But the other 4 galaxies, which
are about 270,000,000 light years in the background, are a tightly clustered,
strongly interacting group. And they are not alone, either. Off to the southeast
from the quintet is the small spiral galaxy NGC-7320C. A few hundred million
years ago, NGC-7320C plowed through the 4 clustered galaxies from behind (as
seen from Earth), and pulled out the large tidal tail that can be seen extending
from NGC-7319.
flashlight requires no batteries. It uses
Faraday’s Principle of Magnetic
Induction and a bright LED to produce
light without batteries. A 30-second
shaking can recharge the capacitor to
produce enough energy to provide about
5 minutes of light.
Today, NGC-7318B is doing the colliding, and as a result of that collision, a
colossal shock wave, 130,000 light years long, is careening through the cluster.
That shock wave was seen by the Chandra X-ray telescope in July 2000. In
December 2005, the Spitzer Science Center released an image of the same shock
wave, taken by the infrared Spitzer Space Telescope. The Chandra image traces
extremely hot, ionized gas. The Spitzer image traces extremely hot molecular
hydrogen. The Chandra image is not surprising, hot ionized gas is expected at a
shock. But the Spitzer image is a surprise, because the presence of so much
molecular hydrogen is unexpected.
Larry Guerra has also added a red filter behind the
front lens and shield around the LED to make the
flashlight night observing compatible. The flashlight
come in two version, one is decorated with LAAS club
name or Logo, one is undecorated. It is sold at $12 –
profits go to the LAAS– (compare to $13-15, plus
shipping online or $19 at Big 5 Sporting store, which
comes without red filter, shield, or LAAS logo).
We all know that the universe is dominated by hydrogen gas. But most of it is
atomic hydrogen, and much of that is ionized. Atomic hydrogen cannot normally
form molecular hydrogen as a gas, there has to be a surface of some kind for the
reaction to take place on. So, atomic hydrogen usually forms molecular hydrogen
in the presence of dust grains, where the surface of the grain acts as a catalyst to
make the chemistry work. But in the case of Stephan’s Quintet, that is not the
case. We speculate that the molecular hydrogen is formed in the wake of the
shock wave, where the gas is rapidly cooling, much more rapidly than under any
normal circumstances. It may be that the Spitzer Space Telescope has found a
new way to make molecular hydrogen, and has done it in one of our favorite
objects.
Orders can be placed by sending a check or money order in the amount of $12.00 +
$2.00 S&H paid in the order of
Rachel Llamas at P.O BOX 1320 SOUTH GATE, CA 90280
Blvd
Gabriel
Garvey Ave
Orange
Ave
LAAS Bulletin
San
10 Freeway
N
Page 4
Del Mar Ave
Valley Blvd
New
Ave
Garfield Ave
Alhambra Ave
(The place to build your telescope)
Atlantic Blvd
Stephan’s Quintet, also known as Hickson Compact Group 92, is the seen of a
great cosmic collision, which can only be guessed at in visible images, but is
revealed in its full glory in X-rays & infrared. It is the closest of many such
groups, and the easiest to study. The focus of many research programs by
professional astronomers, and also a favorite of amateurs, Stephan’s Quintet is
one of the more interesting deep sky objects to look for in your dark sky
observing. —
Map to Monterey Park Observatory
Vol 80, issue 4
Graves Ave
Garvey Ranch
Park Observatory
Page 13
LOANER CORNER
Saturn is just past opposition and is in a good
position for viewing in the evening. Orion and
Taurus have regained control of the winter nights
and spring is only two months away. Check out one
of the LAAS loaner telescopes and take advantage
of the clear winter
nights.
LAAS-2
LAAS-1 - 4.5” f/8
Celestron reflector
on a solid Polaris
equatorial mount. It
comes equipped with
a Kellner eyepiece, two Orthoscopics, and a
collimation tool. These two 4.5” reflectors are
good telescopes for beginners to learn with since
they are both small enough to be easily carried
and set up, but with enough aperture to provide
good views.
The seeing was pretty good, thanks to most of the security lights turned off.
Seeing Saturn produced many Wow's !. Outreach participants were Tom Drouet,
Herb Kraus, Regie Flores, Paul Wicker, and Don DeGregori. —
Don DeGregori
THIS MONTH IN HISTORY
April 8,1947, the largest sunspot group recorded was observed on the sun’s
southern hemisphere. Its size was estimated at 7 billion square miles, or 6100
millionths of the Sun’s visible surface. Large sunspots usually measure from 300
to 500 millionths and the Earth surface area is only 169 millionths of the visible
sun. The sunspot lasted several solar rotations.
April 14, 1611 the word telescope was used for the first time by Prince Federico
Cesi at a banquet held by the Pioneer Scientific Society to honor Galileo who
showed the guest Jupiter its moons and other celestial objects. Telescopio in
Italian is formed from two Greek words tele-far and scopeo-see.
LAAS-2 - 4.5” f/8 Tasco reflector on a motorized
Edmund equatorial mount. This telescope has
been upgraded with 1.25” accessories, a 6x30 finder, and very solid wooden legs.
It comes fully equipped with a set of three Kellner eyepieces and a collimation
tool.
LAAS-4 – 6” f/5 reflector by Telescopics on a low Dobsonian mount. It is
equipped with a set of three Orthoscopic eyepieces.
LAAS-8 – 80 mm f/11.4 Selsi refractor on an
equatorial mount. It is equipped with two
Plossl eyepieces and an Orthoscopic.
For further information concerning these
loaner telescopes call: David Sovereign at
(626) 794-0646. —
April 18, 2006 marks the 100th anniversary of the San Francisco Earthquake. At
5:12 am local time a foreshock occurred which was widely felt throughout the
San Francisco Bay area 20 seconds later the main shock occurred which lasted
45 to 60 seconds. People felt the quake from southern Oregon to Los Angeles
and inland as for as central Nevada. The intensity measured on the Modified
Mercalli Scale was given as VII TO IX and the magnitude numbers range from
7.7 to 8.3 San Francisco was not the only city, which had major damage from the
earthquake the list includes San Jose, Santa Rosa and other smaller cities. Glady
Hansen and Emmet Condor, estimate that over 3,000 deaths were caused directly
or indirectly by the catastrophe. This is from a population of 400,000 in San
Francisco.
A Portion of Emma m. Burke eyewitness account:
“The earthquake grew constantly worse, the noise deafening; the crash of dishes,
falling pictures, the rattle of the flat tin roof, bookcases being overturned the
piano hurled across the parlor, the groaning and straining of the building itself,
broken glass and falling plaster, made such a roar that no one noise could be
distinguished.”
Part of Dr. George Blumer Eyewitness account:
When the water gave out it was decided to check the spread of the fire in certain
districts by blowing up houses.
Some more facts: The number of people left homeless was 225,000. The number
of building destroyed was over 28,000. Estimated property damage 400,000,000
in 1906 money. —
Mary Brown
LAAS-4
Page 14
was hit with his presentation.
LAAS Bulletin
Vol 80, issue 4
Page 3
OUR 80th YEAR OF
ASTRONOMY IN LOS ANGELES
Los Angeles Astronomical Society
Griffith Observatory Satellite
4800 Western Heritage Way
Los Angeles, CA 90027
(213) 673-7355
Change of Address, Membership:
Penny Hunter, LAAS Secretary
(323) 664-9781
LAAS Officers:
President . . . . . . . . . . . . David Sovereign
(626) 794-0646
Vice President . . . . . . . . . . . Mary Brown
[email protected]
Treasurer . . . . . . . . . . . . . Darrell Dooley
[email protected]
Secretary . . . . . . . . . . . . . . Wendy Brown
[email protected]
Recording Secretary . . . . . PJ Goldfinger
(323) 953-6869
Volunteers:
Library . . . . . . . . . . . . . . . . . Mary Brown
[email protected]
Outreach . . . . . . . . . . . . . Don DeGregori
[email protected]
[email protected]
Loaner Scopes . . . . . . . . Dave Sovereign
(626) 794-0646
Messier Program . . . . . . . . Norm Vargas
(626) 288-4397
New Members . . . . . . . . . . . . . . . . . TBA
Speakers Bureau . . . . . . . Tim Thompson
[email protected]
Youth Liaison . . . . . . . . . . . . . . . . . .TBD
LAAS Bulletin Editor . . David Nakamoto
[email protected]
Bulletin Printers and Web Site Managers
Peter De Hoff & Minghua Nie
[email protected]
Contributing Editors . . . . . . .Mary Brown
[email protected]
Don DeGregori
[email protected]
David Sovereign
(626) 794-0646
I
Editor ’s
Message
’ve received the news as this bulletin
was going to press that our
President, David Sovereign, was in
the hospital for a week. I’d like to wish
Dave a quick recovery and hope he can
return to his daily routine soon. Due to
this there will be no President’s
Message this month.
This month sees three telescopes for
sale and two mirror blanks being
offered! Spring cleaning?
Please send all written correspondence,
other than bulletin material, to:
LAAS
4800 Western Heritage Way
Los Angeles, CA 90027.
There will be one more change of
address when Griffith Observatory reopens.
For those wishing to submit material
for the bulletin, the deadline is the 10th
of each month to provide the necessary
the time to prepare all material into the
bulletin and get it to our printers in
time. —
David Nakamoto
The Outreach Program
LAAS Outreach participated in a Star
Party at Irwin Elementary School in La
Puente on Feb 23rd.
It was very successful and the kids,
parents, and teachers appreciated us
c o mi n g o u t . It was h e l d o n
the school grounds. Paul Wicker
transformed again to Galileo Guy and
(Continued on page 3)
Page 2
LAAS Bulletin
EVENTS CALENDAR
Date
Event
Location
Apr 1st (Sat)
Public Star Party
Griffith Observatory Satellite
Moon and Saturn
Apr 10th (Mon)
General Meeting
The speaker is scheduled to be Amanda
Mainzer of JPL
The topic is Brown Dwarfs.
Apr 29th (Sat)
Dark Sky Night
Lockwood Valley
May 6th (Sat)
Public Star Party
Griffith Observatory Satellite
Moon and Saturn
May 8th (Mon)
General Meeting
The speaker is To Be Determined.
May 27th (Sat)
Dark Sky Night
Lockwood Valley
A reminder ― The board meeting is held on the Wednesday night prior to the
general meeting, at Garvey Ranch Park. It starts at 8:00 pm
The Monday general meetings starts at 7:30 pm
LAAS Home Page: http://www.laas.org
LAAS Bulletin Online: http://www.laas.org/bulletin.html
Membership Annual Dues:
Youth
$ 20.00
Regular (18-65)
$ 35.00
Senior Citizen (65 and up)
$ 20.00
Senior Family
$ 30.00
Family
$ 50.00
Group or Club
$ 50.00
Life
$ 500.00
Additional fees:
Charter Star member
$ 30.00
Star member, with pad
$ 70.00
Star member, no pad
$ 60.00
(Membership due date is indicated on the mailing label)
Vol 80, issue 4
HANDY PHONE
LIST
LAAS Answering Machine ...... (213) 673-7355
Griffith Observatory
Program .............................. (323) 664-1191
Offices ................................. (323) 664-1181
Sky Report .......................... (323) 663-8171
Lockwood Site ........................ (661) 245-2106
(not answered, arrange time with caller.
Outgoing calls – collect or calling card)
Mt. Wilson Institute ................. (626) 793-3100
Page 15
LOS ANGELES ASTRONOMICAL SOCIETY
FOR SALE
Small Rich Field Reflector
This Bausch and Lomb telescope was donated by Tom Dorff, one of our previous
presidents. It has been refurbished and remounted as an equatorial. Our shop
director tested the mirror and discovered that it has a smooth parabolic figure. It
was used at the December 10th public star party where it gave very good images.
Primary Mirror Diameter – 130 mm (5.1”)
Focal Length – 715 mm (28.1”) f/5.5
Secondary Mirror – 1.3” elliptical
Finder – full aperture achromatic 6x30.
Focuser is a 1.25” helical with a removable extension tube about 2” long.
Mount is an older Jaegers light duty equatorial with 5/8” shafts which has been
upgraded with bronze bushings on both axes.
Drive is a modified Edmund with a 96 tooth bronze gear and a 1/15 RPM
synchronous motor..
Tripod legs are all aluminum (no plastic here).
The telescope comes equipped with a Meade 25 mm Modified Achromatic
eyepiece.
Note: There is a scratch in the coating of the primary that does not affect
performance. The mirror was inspected from the rear to verify that the scratch did
not extend to the glass.
Asking $175 (proceeds go to the LAAS).
Contact Dave Sovereign at (626) 794 – 0646 —
The LAAS Board of Directors would like you to take a brief look at the address
page of your bulletin. Near the bottom right is your dues date and a note if we have
your correct email address on file. In the event that you have "No Email Address
on File" or have a "Bad Email Address on File," we would like for you to send us
your correct email address to [email protected]. Email addresses are not shared with
anyone and are used by the Board to occasionally send out notices in regards to
LAAS activities.
Additionally, if it is convenient for you, the Board would like for you to elect to
receive an email notification for the presence of the bulletin online. The online
version of the bulletin usually comes out several days prior to you receiving the
print copy and saves the club a great deal of money in printing and mailing
costs.
Finally, take a look at your Dues Date. If it is coming up soon, please send our
Treasurer the renewal funds so that we may update our records accordingly. Thank
you for your time.
BULLETIN
volume 80, issue 4 April 2006
Stephan’s Quintet
By Tim Thompson
Stephan’s Quintet, a tight grouping of 5 galaxies, is one of the better known targets
for dedicated deep sky observers. It was originally discovered by Edouard Jean
Marie Stephan (1837-1923), in either 1876 or 1877, depending on who tells the tale,
using the Foucault 80-cm (31.5 inch) reflecting telescope at the Marseilles
Observatory in France. It can be found in the constellation of Pegasus, at a right
ascension 22h 35m 57s, and declination +33d 57m 36s.
(Continued on page 4)
Inside this issue
Stephan’s Quintet (Tim Thompson) ······································ 1,4-7
Contact Information ······························································ 2
Editor’s Message (David Nakamoto) ··································· 2
Outreach Program (Don DeGregori) ···································· 2
This Month In History (Mary Brown) ·································· 3
The Art of Observing (David Nakamoto) ···························· 8-11
Two Mirror Blanks ······························································· 12
Desert Sunset Star Party························································ 12
“Shake It” flashlight ····························································· 13
Monterey Park Observatory Map ········································· 13
Loaner Corner (David Sovereign) ········································ 14
Events Calendar ··································································· 15
Membership Information ····················································· 15
Telescope for Sale (David Sovereign) ·································· 16
Message From the Board (Peter DeHoff) ····························· 16
Notes, corrections, questions, ideas, articles? All are welcome at:
[email protected].
The LAAS Board of Directors. —
Page 16
LAAS Bulletin
Page 1
LAAS Bulletin