As we all know, the maximum speed of light in a vacuum is about 186,000
miles per second.

If light slows down when say going through air or glass (or any
transparent subtance), it is supposed to then speed up again when it
gets out of that subtance.
     For example.  Light goes through the atmosphere and then goes out
into the vaccum of space, it then picks up to its normal cruising speed
of 186,000 m/p/s.  At least from what I understand.
     The question is, if that is so, where is the energy coming from to
re-accelerate it back up to its normal cruising speed?  That seems to
go against the Law of Concervation of Energy.

   Bob N.

Hello, Bob.

Find a copy of Richard Feynman's "QED".  All will be revealed...

Tony


starman361 wrote:
>
> As we all know, the maximum speed of light in a vacuum is about 186,000
> miles per second.
>
> If light slows down when say going through air or glass (or any
> transparent subtance), it is supposed to then speed up again when it
> gets out of that subtance.
> For example. Light goes through the atmosphere and then goes out
> into the vaccum of space, it then picks up to its normal cruising speed
> of 186,000 m/p/s. At least from what I understand.
> The question is, if that is so, where is the energy coming from to
> re-accelerate it back up to its normal cruising speed? That seems to
> go against the Law of Concervation of Energy.
>
> Bob N.
>
>

Checking the listings this week, this particular property is still
available, and at the reduced asking price of 89900.  Seems too good a
good deal.  Anyone interested?

http://www.riliving.com/PropSearch/lndformdetails.asp?MLSid=550049&indiv=1

Recent observations posted on the MPML Yahoo discussion group
indicate the impact probability is at least 99% and will occur
somewhere over northern Africa or southern Europe.  The possible
impact time is estimated to be about 10:46 EST Oct. 6.

The note below was posted on the ATMoB discussion group.

   Bob N.

*****************************************************************

Rock From Space To Burn Up Over Africa
This is an AstroAlert from Sky & Telescope.
October 6, 2008

----------------------------------------------------------------------
----------

A very tiny asteroid, not much more than 10 feet across, will enter
Earth's atmosphere over Sudan in Africa tonight, October 6-7, 2008,
near 2:46 Greenwich Mean Time. Most likely it will burn up before
hitting the ground, but it could produce a spectacular fireball, or
bolide, in the night sky equivalent to the explosion of about a
kiloton of TNT.
These are the assessments of astronomers Andrea Milani of NEODyS in
Italy and Steve Chesley (Jet Propulsion Laboratory). They are
concerned that eyewitnesses might misinterpret the event as some type
of hostile military action. Says Milani, "The earlier the public
worldwide is aware that this is a natural phenomenon, which involves
no risk, the better."

The first observatory to capture images of 2008 TC3 (as it's now
designated) were Richard Kowalski and colleagues of Mount Lemmon
Observatory in Arizona, about 12 hours ago. Confirming measurements
were quickly secured by amateur astronomer James McGaha at Sabino
Canyon Observatory near Tucson, and then by Gordon Garrad and others
at Australia's Siding Spring Observatory and also Christopher Jacques
and E. Pimentel using the Global Rent-a-Scope site in Moorook, near
Melbourne.

First to point out that the incoming object was heading right for a
collision with Earth's atmosphere was Bill Gray of Project Pluto, in
a post earlier today to the Minor Planet Mailing List. Canadian
amateur Andrew Lowe has independently calculated the object's point
of entry to be over Sudan.

The object's entry might be visible as far north as southern Europe
and the Middle East. Its location in the sky, however, is completely
dependent on an observer's geographic location. As further details
become known, be sure to look at the online version of this
AstroAlert at SkyandTelescope.com/AstroAlert for possible updates.


Roger W. Sinnott
Senior Editor
Sky & Telescope
rsinnott@...

More info from a NASA news release:

   Bob N.

********************************************

http://neo.jpl.nasa.gov/news/news159.html

Small Asteroid Predicted to Cause Brilliant Fireball over Northern
Sudan
Don Yeomans
NASA/JPL Near-Earth Object Program Office
October 6, 2008

A very small, few-meter sized asteroid, designated 2008 TC3, was found
Monday morning by the Catalina Sky Survey from their observatory near
Tucson Arizona. Preliminary orbital computations by the Minor Planet
Center suggested an atmospheric entry of this object within a day of
discovery. JPL confirmed that an atmospheric impact will very likely
occur during early morning twilight over northern Sudan, north-eastern
Africa, at 2:46 UT Tuesday morning. The fireball, which could be
brilliant, will travel west to east (from azimuth = 281 degrees) at a
relative atmospheric impact velocity of 12.8 km/s and arrive at a very
low angle (19 degrees) to the local horizon. It is very unlikely that
any sizable fragments will survive passage through the Earth's
atmosphere.

Objects of this size would be expected to enter the Earth's atmosphere
every few months on average but this is the first time such an event
has been predicted ahead of time.

**********************************************************

--- In skyscrapers_rias@yahoogroups.com, "starman361"
<bob_napier@...> wrote:
>
> Recent observations posted on the MPML Yahoo discussion group
> indicate the impact probability is at least 99% and will occur
> somewhere over northern Africa or southern Europe.  The possible
> impact time is estimated to be about 10:46 EST Oct. 6.
>
> The note below was posted on the ATMoB discussion group.
>
>   Bob N.
>
> *****************************************************************
>
> Rock From Space To Burn Up Over Africa
> This is an AstroAlert from Sky & Telescope.
> October 6, 2008
>
> --------------------------------------------------------------------
--
> ----------
>
> A very tiny asteroid, not much more than 10 feet across, will enter
> Earth's atmosphere over Sudan in Africa tonight, October 6-7, 2008,
> near 2:46 Greenwich Mean Time. Most likely it will burn up before
> hitting the ground, but it could produce a spectacular fireball, or
> bolide, in the night sky equivalent to the explosion of about a
> kiloton of TNT.
> These are the assessments of astronomers Andrea Milani of NEODyS in
> Italy and Steve Chesley (Jet Propulsion Laboratory). They are
> concerned that eyewitnesses might misinterpret the event as some
type
> of hostile military action. Says Milani, "The earlier the public
> worldwide is aware that this is a natural phenomenon, which
involves
> no risk, the better."
>
> The first observatory to capture images of 2008 TC3 (as it's now
> designated) were Richard Kowalski and colleagues of Mount Lemmon
> Observatory in Arizona, about 12 hours ago. Confirming measurements
> were quickly secured by amateur astronomer James McGaha at Sabino
> Canyon Observatory near Tucson, and then by Gordon Garrad and
others
> at Australia's Siding Spring Observatory and also Christopher
Jacques
> and E. Pimentel using the Global Rent-a-Scope site in Moorook, near
> Melbourne.
>
> First to point out that the incoming object was heading right for a
> collision with Earth's atmosphere was Bill Gray of Project Pluto,
in
> a post earlier today to the Minor Planet Mailing List. Canadian
> amateur Andrew Lowe has independently calculated the object's point
> of entry to be over Sudan.
>
> The object's entry might be visible as far north as southern Europe
> and the Middle East. Its location in the sky, however, is
completely
> dependent on an observer's geographic location. As further details
> become known, be sure to look at the online version of this
> AstroAlert at SkyandTelescope.com/AstroAlert for possible updates.
>
>
> Roger W. Sinnott
> Senior Editor
> Sky & Telescope
> rsinnott@...
>

http://www.motorrepair.us/highres/index.html

http://news.bbc.co.uk/2/hi/health/7656528.stm

Friday, October 17th > Woman's Wilderness Weekend @ Alton Jones Campus

We have  had only one other Skyscraper that volunteered for the Woman's
Wilderness Weekend at Alton Jones.  Dave and myself cannot handle a group this
size by ourselves so we had no choice but to regrettably DECLINE from the
invitation. This event has been CANCELED.

Bob F.

---- bforgiel@... wrote:

There is still a spark of life in this event. If we can come up with a few more
scopes by mid day Thursday we might be able to pull this off. If you think you
can attend, send me an email with a # you can be reached at.

Bob Forgiel


---- bforgiel@... wrote:
> Friday, October 17th > Woman's Wilderness Weekend @ Alton Jones Campus
>
> We have  had only one other Skyscraper that volunteered for the Woman's
Wilderness Weekend at Alton Jones.  Dave and myself cannot handle a group this
size by ourselves so we had no choice but to regrettably DECLINE from the
invitation. This event has been CANCELED.
>
> Bob F.
>
> ---- bforgiel@... wrote:

This international event encourages everyone to go outside, look
skywards after dark, count the stars they see in certain
constellations, and report what they see online.  This Windows to the
Universe Citizen Science Event is designed to encourage learning in
astronomy!

http://www.windows.ucar.edu/citizen_science/starcount/

Below is a description of the event as posted on the ATMoB web site:

"Don't miss out on the worldwide star count October 20 - November
3rd, 2008.  For those who have not participated before, you don't
need a telescope - just go out and look up.   The number of stars
visible depends on the quality of the night sky.  You'll learn how to
measure the limiting magnitude of the night sky at your location,
report the data, and help contribute to a database measuring global
light pollution.  This is a useful project for teaching kids and
adults about the impact of artificial lighting on our environment.
Help raise awareness about the decreasing quality of our night skies
and the ongoing loss of our ability to study or simply enjoy the
night sky.   Investigate the economic and environmental impacts of
light in your town!"

   Bob N.

World's Toughest Fixes: Giant Telescope
 
"Sean Riley helps a team of engineers transport and cleans a 23-ton telescope
mirror that's part of the world's largest combined telescope in Chile's Atacama
Desert."
 
It's on as I type, but will be shown again on NGC (National Geographic):
 
Sat     11/1 10:00 p.m.
Thurs. 11/2 1:00 a.m.
Mon.   11/3 1:00 p.m.
 
Marilyn

[Non-text portions of this message have been removed]

A member of the ATMoB Club in Boston has a few items for sale.  Here
is the listing.  Email him at his email address below.

   Bob N.

***************************************************************

Re: [Atmob-discuss] Telescopes and related for sale - repost

Hello All,

I have a few items I would like to offer for sale. Please respond to
me directly if you are interested in any of these items.
(Bob_Smith@...)

Thanks.
Bob Smith

Telescopes
-       13.1 inch / F4.5 Dobsonian telescope. Based on a design by
Albert Highe and using Coulter optics. Uses an Astrosystems spider
with a 2.6 inch diagonal. Includes 2 inch Moonlite Crayford focuser
and Sky Commander digital setting circles. Also includes a Rigel
Systems Quikfinder 1x finder and an 8x50mm right angle viewfinder. An
article about the scope can be seen at
http://www.atmob.org/library/member/bsmith/bobsmith.htm. $1000 or
best reasonable offer.

-       Meade 8-inch / F10 Model LX90 Schmidt-Cassegrain telescope
with AutoStar controller, tripod, right-angle 8x50mm viewfinder and
an aluminum dew shield. Comes with a Meade 2-inch right-angle
eyepiece holder and Meade Series 4000 26mm Super Plossl eyepiece.
Always stored in a Pelican 1650 airtight carry case (included). $900
or best offer.

-       Orion ShortTube 80 refracting telescope. 80x400mm/F5.
Includes 25mm Orion plossl eyepiece, right angle viewfinder and Orion
2x shorty barlow lens; all stored in an aluminum carry case. Includes
Equitorial mount tripod with Orion EQ1 motor drive. $200.

Eyepieces

- Tele Vue 55mm 2 inch Plossl eyepiece. As new. $150.
- Tele Vue 40mm Plossl eyepiece. As new. $75.  - Sale Pending -
- Tele Vue 32mm Plossl eyepiece. As new. $75.
- Tele Vue 20mm Plossl eyepiece. As new. $60.
- Tele Vue 12mm Radian eyepiece. $150.
- Tele Vue 9mm Nagler Type 6 eyepiece. As new. $225.
- Tele Vue 5mm Radian eyepiece. As new. $175.
- University Optics 9mm Orthoscopic eyepiece. As new. $40.
- University Optics 7mm Orthoscopic eyepiece. As new. $40.
- University Optics 5mm Orthoscopic eyepiece. As new. $40.

Accessories

- Meade Series 4000 Lunar/Planetary 6 piece filter set. 1.25 inch
filters in fold up nylon case. Includes Yellow #12, Orange #21, Red
#23A, Green #58, Blue #80A and Neutral Density #ND96(0.9). As new.
$50.
- Meade #911N 2 inch Narrowband filter for LX90. Threaded to mount
directly onto the LX90. As new. $75.
- Meade Series 4000 F6.3 focal reducer/field flattener. As new. $75.
- Meade model 140 2x air spaced triplet telenegative amplifier. $75.
- Sirius Optics PC1 1.25 inch planetary contrast filter. As new. $40.
- Thousand Oaks Optical Type 2+ 8 inch full aperture solar filter. As
new. $75.
- JMI Motofocus motorized focuser. $40.
- Interstate Deep Cycle Battery. 12V/18AH. Model PC12180F. $20.
- Schumacher 1.5 Amp automatic battery charger/maintainer. $10.
- Orion plastic carry case. 17x12x6". $10.
- Aluminum carry case, 18x13x6" $10.
- Doskocil airtight plastic carry case, 20x16x9 inches. $35.

Blow the dust off your scopes and join the parties!!

We just finished :
Friday Oct. 17th / Woman's Wilderness Weekend
Thursday Oct. 23rd /  30 Girl Scouts at Seagrave

Still to come !!!!

Friday Oct. 24th  /  joint members night at Ninigret Park
Wednesday Nov. 5th / 30+ Scouts at Seagrave
Thursday Dec. 4th / Scouts at Seagrave
Friday Dec. 5th / possible scouts at Seagrave
Friday Jan. 23rd / Another Woman's Wilderness Weekend

It's a busy schedule so please sign up!!


Then 30+ scouts ate Seagrave on November

Hi Group, here are some awesome images of Enceladus from the Cassini
spacecraft.
Including an animation.
http://www.boston.com/bigpicture/2008/10/enceladus_up_close.html

Clear Skies

Tracey

Amazing images.. I loved one of the comments, "Where's the Monolith"

Graham



   _____

From: skyscrapers_rias@yahoogroups.com
[mailto:skyscrapers_rias@yahoogroups.com] On Behalf Of T Haley
Sent: Sunday, October 26, 2008 08:13
To: skyscrapers_rias@yahoogroups.com
Subject: [skyscrapers_rias] Amazing Enceladus pictures from Cassini



Hi Group, here are some awesome images of Enceladus from the Cassini
spacecraft.
Including an animation.
http://www.boston.
<http://www.boston.com/bigpicture/2008/10/enceladus_up_close.html>
com/bigpicture/2008/10/enceladus_up_close.html

Clear Skies

Tracey





[Non-text portions of this message have been removed]

Ah yes Graham...a nice sound byte of "Also sprach Zarathustra" 
would complete the video nicely!


Roger

PS I have attached ( I hope)  a small midi file of that music so as to not
uplaoad any longer files for those without high speed connnections

[Non-text portions of this message have been removed]

The file did note come through…

For those interested  Richard Strauss composition  can be found here (along
with the opening shots of 2001 A space Odyssey)

http://www.youtube.com/watch?v=cWnmCu3U09w



Longer  version  concert du DFO au conservatoire de Paris le 21 decembre
2007 dirigé par Pierre Michel Durant

http://www.youtube.com/watch?v=BqF2Li6Iwkc





   _____

From: skyscrapers_rias@yahoogroups.com
[mailto:skyscrapers_rias@yahoogroups.com] On Behalf Of Roger Forsythe
Sent: Monday, October 27, 2008 10:05
To: skyscrapers_rias@yahoogroups.com
Subject: [skyscrapers_rias] Re: Amazing Enceladus pictures from Cassini



Ah yes Graham...a nice sound byte of "Also sprach Zarathustra" would
complete the video nicely!

Roger

PS I have attached ( I hope) a small midi file of that music so as to not
uplaoad any longer files for those without high speed connnections

[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]

Here is a NASA news release about a nearby star Epsilon Eridani and
the two asteroid belts it contains.

   Bob N.

******************************************************************


http://www.jpl.nasa.gov/news/news.cfm?release=2008-197

Closest Planetary System Hosts Two Asteroid Belts
Jet Propulsion Laboratory
October 27, 2008

New observations from NASA's Spitzer Space Telescope indicate that the
nearest planetary system to our own has two asteroid belts. Our own
solar system has just one.

The star at the center of the nearby system, called Epsilon Eridani,
is
a younger, slightly cooler and fainter version of the sun. Previously,
astronomers had uncovered evidence for two possible planets in the
system, and for a broad, outer ring of icy comets similar to our own
Kuiper Belt.

Now, Spitzer has discovered that the system also has dual asteroid
belts. One sits at approximately the same position as the one in our
solar system. The second, denser belt, most likely also populated by
asteroids, lies between the first belt and the comet ring. The
presence
of the asteroid belts implies additional planets in the Epsilon
Eridani
system.

"This system probably looks a lot like ours did when life first took
root on Earth," said Dana Backman, an astronomer at the SETI
Institute,
in Mountain View, Calif., and outreach director for NASA's Sofia
mission. "The main difference we know of so far is that it has an
additional ring of leftover planet construction material." Backman is
lead author of a paper about the findings to appear Jan. 10 in the
Astrophysical Journal.

Asteroid belts are rocky and metallic debris left over from the early
stages of planet formation. Their presence around other stars signals
that rocky planets like Earth could be orbiting in the system's inner
regions, with massive gas planets circling near the belts' rims. In
our
own solar system, for example, there is evidence that Jupiter, which
lies just beyond our asteroid belt, caused the asteroid belt to form
long ago by stirring up material that would have otherwise coalesced
into a planet. Nowadays, Jupiter helps keep our asteroid belt confined
to a ring.

Astronomers have detected stars with signs of multiple belts of
material
before, but Epsilon Eridani is closer to Earth and more like our sun
overall. It is 10 light-years away, slightly less massive than the
sun,
and roughly 800 million years old, or one-fifth the age of the sun.

Because the star is so close and similar to the sun, it is a popular
locale in science fiction. The television series Star Trek and
Babylon 5
referenced Epsilon Eridani, and it has been featured in novels by
Issac
Asimov and Frank Herbert, among others.

The popular star was also one of the first to be searched for signs of
advanced alien civilizations using radio telescopes in 1960. At that
time, astronomers did not know of the star's young age.

Spitzer observed Epsilon Eridani with both of its infrared cameras and
its infrared spectrometer. When asteroid and comets collide or
evaporate, they release tiny particles of dust that give off heat,
which
Spitzer can see. "Because the system is so close to us, Spitzer can
really pick out details in the dust, giving us a good look at the
system's architecture," said co-author Karl Stapelfeldt of NASA's Jet
Propulsion Laboratory, Pasadena, Calif.

The asteroid belts detected by Spitzer orbit at distances of
approximately 3 and 20 astronomical units from the star (an
astronomical
unit is the average distance between Earth and the sun). For
reference,
our own asteroid belt lies at about 3 astronomical units from the sun,
and Uranus is roughly 19 astronomical units away.

One of the two possible planets previously identified around Epsilon
Eridani, called Epsilon Eridani b, was discovered in 2000. The planet
is
thought to orbit at an average distance of 3.4 astronomical units from
the star -- just outside the innermost asteroid belt identified by
Spitzer. This is the first time that an asteroid belt and a planet
beyond our solar system have been found in a similar arrangement as
our
asteroid belt and Jupiter.

Some researchers had reported that Epsilon Eridani b orbits in an
exaggerated ellipse ranging between 1 and 5 astronomical units, but
this
means the planet would cross, and quickly disrupt, the newfound
asteroid
belt. Instead, Backman and colleagues argue that this planet must
have a
more circular orbit that keeps it just outside the belt.

The other candidate planet was first proposed in 1998 to explain
lumpiness observed in the star's outer comet ring. It is thought to
lie
near the inner edge of the ring, which orbits between 35 and 90
astronomical units from Epsilon Eridani.

The intermediate belt detected by Spitzer suggests that a third planet
could be responsible for creating and shepherding its material. This
planet would orbit at approximately 20 astronomical units and lie
between the other two planets. "Detailed studies of the dust belts in
other planetary systems are telling us a great deal about their
complex
structure," said Michael Werner, co-author of the study and project
scientist for Spitzer at JPL. "It seems that no two planetary systems
are alike."

JPL manages the Spitzer mission for NASA's Science Mission
Directorate,
Washington. Science operations are conducted at the Spitzer Science
Center at the California Institute of Technology in Pasadena. Caltech
manages JPL for NASA. More information about Spitzer is at
http://www.spitzer.caltech.edu/spitzer and
http://www.nasa.gov/spitzer .
More information about extrasolar planets and NASA's planet-finding
program is at http://planetquest.jpl.nasa.gov .

Media contact: Whitney Clavin 818-354-4673
Jet Propulsion Laboratory
whitney.clavin@...

2008-197

PLANET MAN


This is the fascinating story of Dantro, The Planet Man, troubleshooter for the
League of Planets organization, the law enforcement body for peace and justice
in the celestial world -- whose headquarters and center of operations are
situated on the capital of all planets, Planteria Rex.

From Mercury to Pluto, where ever danger threatens the universe, you will find
Dantro the Planet Man fighting for fair play.

The Planet Man was a juvenile science ficton series of the 1950's transcribed
and syndicated by Palladium Radio Productions.

The stories are campy and predictable, but silly fun none the less. Good for a
laugh or for bedtime stories for younger listeners.
 
[end of copy/paste description]

Individual, 12 minute, programs from the series can be downloaded from this
page:
 
http://www.archive.org/details/OTRR_Planet_Man_Ver2_Singles
 
The entire, Old Time Radio Researcher Group certified series, that includes all
the individual programs plus some additional information, can be downloaded
here:
 
http://www.archive.org/details/OTRR_Certified_Planet_Man_Ver2

[Non-text portions of this message have been removed]

http://saturn.jpl.nasa.gov/news/events/enceladus20081031/index.cfm

And the best images will be found here (usually posted within 2 days
of the event):
http://ciclops.org/

http://dawn.jpl.nasa.gov/mission/journal_10_30_08.asp

Dawn Journal
Dr. Marc Rayman
October 30, 2008

Dear Presidawntial Candidawnts,

The Dawn spacecraft continues on course and on schedule for its
bold campaign to unexplored worlds. The probe is thrusting gently
with its ion propulsion system, as it has been for most of its
time in space, gradually modifying its path around the Sun.

New research in the well-named Department of Recent Earthling
Communications and Knowledge at the increasingly popular Galactic
University of Fatuity and Frivolity (GUFF) has revealed that the
significant majority of these logs written since Dawn's
interplanetary cruise phase commenced on December 17, 2007,
have begun with something similar to that
introductory paragraph. That may not be very surprising, as
humankind would not be able to accomplish this ambitious and
exciting mission without a reliable, ion-propelled spacecraft.
(Note to other readers: for bureaucratic reasons, earthlings have
chosen not to collaborate with more technologically advanced
species on this mission. Rest assured, though, that it's nothing
personal!) Nevertheless, as you will see in a second (assuming you
can read about 800 words per second), this familiar story will
change quite soon, as the typical content of our opening remarks
will no longer be fully applicable. First, let's review what Dawn
has accomplished since the last log besides 28 days of thrusting.

On September 29, as its own silent but joyous celebration of its
first anniversary of being in space was
winding down, the spacecraft stopped thrusting so mission
controllers could conduct routine maintenance on components in 2
of its subsystems: attitude control and ion propulsion. (Thrusting
is suspended during these activities principally because the
orientation in which the main antenna is aimed at Earth is
different from the orientation required to point an ion thruster
in the direction needed for changing the craft's course through
space.) Attitude control is responsible for the orientation (known
to engineers as "attitude") of the probe in the zero-gravity of
spaceflight. Despite its name, this subsystem is as pleasant a
member of the onboard crew as any other. Ion propulsion, of
course, reshapes the spacecraft's orbit so it will rendezvous with
distant Vesta and Ceres and maneuver at each to obtain the
precious scientific secrets they hold.

Some of the work during this week was to verify that the contents
of the computer memory in certain components remained intact. On
September 30, engineers confirmed that the memory in each of the 2
ion propulsion computer control units was in good condition. On
October 2, the backup star tracker was tested, and it also remains
healthy and ready for use whenever needed. A star tracker helps
the attitude control system determine the orientation of the
spacecraft by imaging groups of stars and recognizing patterns,
much as you might orient yourself on a dark, cloudless night if
you were familiar with the constellations. (Readers who travel
frequently, and hence must keep track of where they are in their
galaxy in order to know what the arrangement of stars should be,
have a more difficult problem than Dawn's star trackers face. The
solar system is so tiny compared to interstellar distances that
the views of the stars remain essentially unaffected by where the
spacecraft is, just as the shapes of constellations are the same
for observers anywhere on Earth.)

In addition to performing maintenance on software, the mission
control team needs to keep Dawn's hardware in peak condition. The
3 ion thrusters are mounted on separate mechanical apparatuses
that allow each 8.9-kilogram (19.5-pound) thruster to be pointed
accurately. These thruster gimbal assemblies, known as TGAs to
team members who find themselves too busy to use entire words
(such people are themselves known as being TBTUEW), need to have
lubricant in their bearings redistributed occasionally. Even when
a TGA is in use for an operating thruster (thruster #1 has been
the active one since June, the usual motion
is not enough to accomplish the needed spreading of lubricant.
Therefore, all 3 TGAs were moved through a prescribed pattern,
ensuring that they will be able to continue to operate smoothly
and point correctly.

Dawn is outfitted with 4 reaction wheels, devices whose spin is
controlled electrically. Changing a wheel's spin rate allows the
attitude control system to rotate the spacecraft. The wheels are
mounted in different orientations, but any 3 are sufficient for
normal operations. Wheel #3 has been off since May
On October 2, it was powered on again
and wheel #2 was deactivated, beginning its turn as the backup.

Gyroscopes, which will help attitude control perform the accurate
pointing of science instruments at the 2 protoplanetary
destinations, normally are turned off, as they are not needed for
most of Dawn's assignments along the way. A few times each year
they do need to be operated to ensure they remain in good
condition. The last such time was in May.
On September 29, the units were
activated again, and they remained powered on until October 3.

With all maintenance completed successfully, normal interplanetary
thrusting resumed on October 3. Soon however, interplanetary
thrusting will no longer be the norm. Some of the unusual
principles of an interplanetary journey driven with ion propulsion
were considered in a log written while
Dawn was still gravitationally anchored to Earth. One essential
characteristic of such missions is the long periods of thrusting,
familiar now to those fortunate enough to have followed Dawn's
progress since the beginning of the interplanetary cruise phase.
But, thrusting is not required for the entire voyage; indeed, at
some times thrusting is helpful to the mission and at other times
it would be detrimental. Extensive analysis is devoted to
computing the thrusting schedule, based on factors ranging from
the physical characteristics of the solar system (e.g., the masses
and orbits of Earth, Mars, Vesta, Ceres, and myriad other bodies)
to the capabilities of the spacecraft (e.g., electrical power
available to the ion thrusters to
constraints on when thrusting is not permitted (e.g., during
spacecraft maintenance periods).

As hinted obscurely only a second ago, the period in which
thrusting is beneficial for reaching Vesta on schedule is drawing
to a temporary close. For nearly all of the next 7 months, Dawn
will coast in its orbit around the Sun (just as do most objects in
the solar system, including other spacecraft and planets), no
longer mounted atop a bluish-green pillar of xenon ions. Still,
its orbit will change dramatically during this interval, as its
flight by Mars in February will deflect its path through the solar
system. As we shall see in the next log, to achieve exactly the
gravitational bending needed, the spacecraft will execute some
special thrusting in November and again in January, but very
little indeed.

The interplanetary cruise phase has gone so smoothly that the
completion of thrusting is being reached somewhat sooner than had
been expected earlier in the mission. Commands already stored in
Dawn's central computer will terminate the thrust on October 31 at
3:22 pm PDT. In the next log, we will discuss a bit about the
process the team used to determine that time, as it bears on
another activity planned for November; contrary to what you might
conclude however, leaving enough time for team members to don
their costumes in preparation for going door to door to collect
Halloween treats was not a factor. (Your correspondent, who
disguises himself in costumes at JPL most days, won't need any
extra time at all tomorrow to outfit himself for perfectly
frightening appearances on Halloween.)

Although thrusting will be uncommon over the coming months, there
will be plenty of other news to look forward to in these logs,
including the reversal of Dawn's departure from Earth, the first
attempt to measure the total power generating capability of the
solar arrays, passage of the spacecraft nearly behind the Sun,
plans for and results of the brief visit to Mars, a dramatic
increase in the quality of writing [Note from writer to sponsor:
Now that I've made such a promise to our readers, I hope you'll
come through with that generous raise I've been requesting. Note
from sponsor to writer: OK, you win. We agree to a 2% raise from
the current $0.00 per log, and we will pay 1% of your tuition if
you can buckle down, gain readmission to GUFF, and finally receive
your degree.], and much more.

Dawn is 384 million kilometers (238 million miles) from Earth, or
950 times as far as the moon and 2.58 times as far as the Sun.
Radio signals, traveling at the universal limit of the speed of
light, take 43 minutes to make the round trip.

Welcome to our new members!
Feel free to post messages, replies, or photos. Some members post their
astro-images, or pictures of their scopes and equipment. We hope to get
more Skyscrapers to join in and share!

Clear Skies

Tracey Haley

Hello group, don't forget tonights Nov.7th meeting with Professor Rick
Gaitskell. We have to stick to our "armchair," astronomy during this
crumby weather.
Maybe Saturday night with clear from a good public viewing!

Clear Skies

Tracey Haley

This program premieres on PBS on Monday, Nov 10

http://www.pbs.org/thejourneytopalomar/index.html

http://www.journeytopalomar.org/

Hello all


             Make sure you watch Channel 2  (WGBH/Boston) at 10PM.. as Channel 36
(Rhode Island's PBS station)  has no listings until early 2009!! :(((


Roger

[Non-text portions of this message have been removed]

Hello Group, tonight Wednesday 19th of November is our Observatory
committee meeting, and all should attend. The meeting will start at
7:00pm and we will discuss the issues of key-holders not signing up for
public nights or star parties. I would also like to discuss training
new members and the conditions of the scopes and grounds.
  Please come and join us!

Clear Skies

Tracey Haley

Below is a message addressed to NASA's Solar Sytem Ambassador (SSA)
education and public outreach program.  LCROSS (Lunar CRater
Observing and Sensing Satellite) is a program to try and find water
on the moon's north and south polar regions. Amateurs are invited to
participate in this program leading up to and during the impactor
part of the mission.

Note the discussion group they have set up more specific details
about this project:
http://groups.google.com/group/lcross_observation

   Bob Napier, SSA

*****************************************************************

From Brian Day regarding the LCROSS Observation Campaign, FYI...

A new online discussion group has been set up to facilitate amateur
participation in NASA's LCROSS Observation Campaign. You can join the
group by visiting http://groups.google.com/group/lcross_observation.
Observations by amateur astronomers will help refine new protocols
for observing the moon and increase our knowledge of the moon.

During the months leading up to the launch, amateur astronomers are
encouraged to image the north and south poles of the moon. The goal
is to obtain images that determine the scale of recognizable features
observed in the wider field of view on amateur telescopes when
compared the higher spatial resolution near-infrared IRTF images. A
secondary goal is to compare the dynamic range of images that allow
the verification of detection of subtle variations in topography and
albedo. This exercise also may help amateurs to prepare for obtaining
images of the impact plumes. The impact plumes will occur in shadowed
regions, but these shadowed regions likely will be adjacent to lit
regions of the moon.

NASA's LCROSS mission is scheduled to fly in 2009. It is co-
manifested with LRO; both missions will launch together aboard an
Atlas V out of Cape Canaveral, Fla. LCROSS will use the Centaur upper
stage of the launch vehicle as a kinetic impactor directed at 2.5
km/s into one of the permanently-shadowed craters at the Moon's pole.
The LCROSS spacecraft will fly directly through the resulting plume
of debris, analyzing it for signs of water ice that may have
accumulated within the crater. The debris plume will also be studied
by space-based assets (such as LRO, and HST), ground-based
observatories, and amateur telescopes. Researchers believe that the
LCROSS impact plume may well be observable in amateur telescopes, and
that amateurs may be able to take on a valuable role in this exciting
mission.

This group is designed to facilitate amateur participation in the
LCROSS mission, posting and sharing images that will be of scientific
value before launch, during flight, and during impact.

Please share this information with your colleagues!

---------

Any opinions expressed in this message are strictly my own and do not
necessarily reflect those of NASA, its contracting agencies, or any
other life form in the Universe.

Please note my new email address

Brian H. Day
AETT Technical Lead
LCROSS E/PO Lead
Planners Collaborative
Mailstop 226-4
NASA Ames Research Center
Moffett Field, CA 94035-1000
(650) 604-2605
Brian.H.Day@...

Yikes!!!  What a disaster that would be.  Let's hope it doesn't get by
the planning stages again.  In my mind it doesn't make much sense to
locate a high end theme park like that in northern latitudes anyway ...
I'm not sure that an investment like that could survive on just
seasonal business.

Hopefully our economic downturn will put a stop to this plan! We need
another theme park like a hole in the head. Maybe they should open
a "dark sky," theme park instead!

Clear "Dark Skies," to everyone.

Tracey

--- In skyscrapers_rias@yahoogroups.com, "dwlorraine" <dwlorraine@...>
wrote:
>
> Yikes!!!  What a disaster that would be.  Let's hope it doesn't get
by
> the planning stages again.  In my mind it doesn't make much sense to
> locate a high end theme park like that in northern latitudes
anyway ...
> I'm not sure that an investment like that could survive on just
> seasonal business.
>

--- On Mon, 11/24/08, NASA Science News <snglist@...> wrote:

From: NASA Science News <snglist@...>
Subject: Spectacular Conjunction
To: "NASA Science News" <snglist@...>
Date: Monday, November 24, 2008, 5:30 PM


NASA Science News for November 24, 2008
Venus and Jupiter are converging for a spectacular three-way
conjunction with
the crescent Moon, a rare gathering some astronomers are calling 'the
sky show
of the year.' Today's story tells when and where to look.
FULL STORY at
http://science.nasa.gov/headlines/y2008/24nov_skyshow.htm?list784178
Check out our RSS feed at http://science.nasa.gov/rss.xml!