jccc ewts 091024 cloudy

59
Asteroids, Black Asteroids, Black Swans, Global Swans, Global Catastrophic Risks, Catastrophic Risks, and How to Save and How to Save Civilization Civilization (cloudy night version) (cloudy night version) JCCC Science Center JCCC Science Center Evening with the Evening with the Stars Stars Saturday 24 October 2009 Saturday 24 October 2009

Upload: jay-manifold

Post on 11-May-2015

1.429 views

Category:

Education


0 download

DESCRIPTION

Asteroids, Black Swans, Global Catastrophic Risks, and How to Save Civilization (cloudy night version) -- JCCC Science Center "Evening with the Stars" lecture, given Saturday 24 October 2009. Created by Jay Manifold, board member of the Astronomical Society of Kansas City.

TRANSCRIPT

Page 1: JCCC EwtS 091024 Cloudy

Asteroids, Black Swans, Asteroids, Black Swans, Global Catastrophic Risks, Global Catastrophic Risks,

and How to Save Civilizationand How to Save Civilization(cloudy night version)(cloudy night version)

JCCC Science CenterJCCC Science Center

Evening with the StarsEvening with the StarsSaturday 24 October 2009Saturday 24 October 2009

Page 2: JCCC EwtS 091024 Cloudy

AgendaAgenda

AsteroidsAsteroids• Basics – What/Where/How ManyBasics – What/Where/How Many• Impacts You’ve Heard OfImpacts You’ve Heard Of• Craters You Can VisitCraters You Can Visit• Impacts You Impacts You Haven’tHaven’t Heard Of Heard Of

Black SwansBlack Swans Global Catastrophic RisksGlobal Catastrophic Risks

Page 3: JCCC EwtS 091024 Cloudy

Agenda Agenda (cont’d)(cont’d)

How to Save CivilizationHow to Save Civilization• Think GloballyThink Globally• Act LocallyAct Locally• 2008 TC32008 TC3

Astronomical Society of Kansas CityAstronomical Society of Kansas City

Page 4: JCCC EwtS 091024 Cloudy

What Are Asteroids?What Are Asteroids?• Small solar system bodies that Small solar system bodies that aren’taren’t comets or comets or

meteoroids.meteoroids.

• The formerly largest asteroid, 1 Ceres, is now The formerly largest asteroid, 1 Ceres, is now classified as a classified as a dwarf planetdwarf planet..

• Discovered 1 January 1801 by Giuseppi Piazzi Discovered 1 January 1801 by Giuseppi Piazzi in Palermo, Sicilyin Palermo, Sicily

IAU members gathered at the 2006 General Assembly agreed that a “planet” is defined as a celestial body that(a) is in orbit around the Sun(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium

(nearly round) shape, and(c) has cleared the neighbourhood around its orbit.

(source: http://www.iau.org/public_press/news/release/iau0603/)

Page 5: JCCC EwtS 091024 Cloudy

Where Are Asteroids?Where Are Asteroids?

(source: http://upload.wikimedia.org/wikipedia/commons/f/f3/InnerSolarSystem-en.png)

Page 6: JCCC EwtS 091024 Cloudy

But Where Are They But Where Are They Right Now?Right Now?

(source: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1&orb=1#top)

Page 7: JCCC EwtS 091024 Cloudy

Special Classifications for NEOs – Special Classifications for NEOs – AmorsAmors

(source: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1221&orb=1#top; see also http://www.cfa.harvard.edu/iau/lists/Amors.html )

Page 8: JCCC EwtS 091024 Cloudy

Special Classifications for NEOs – Special Classifications for NEOs – ApollosApollos

(source: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1862&orb=1#top; see also http://www.cfa.harvard.edu/iau/lists/Apollos.html )

Page 9: JCCC EwtS 091024 Cloudy

Special Classifications for NEOs – Special Classifications for NEOs – AtensAtens

(source: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2062&orb=1#top; see also http://www.cfa.harvard.edu/iau/lists/Atens.html )

Page 10: JCCC EwtS 091024 Cloudy

How Many Asteroids Are There?How Many Asteroids Are There?(source: http://www.wwu.edu/depts/skywise/a101_asteroids.html, corrected)(source: http://www.wwu.edu/depts/skywise/a101_asteroids.html, corrected)

dia (km)dia (km) ## tot vol kmtot vol km33

950950 11 4.5 4.5 ×× 10 1088

400400 11 3.4 3.4 ×× 10 1077

200200 1313 5.5 5.5 ×× 10 1077

100100 5050 2.6 2.6 ×× 10 1077

5050 130130 8.5 8.5 ×× 10 1066

2525 500500 4.1 4.1 ×× 10 1066

1010 3,2003,200 1.7 1.7 ×× 10 1066

55 18,00018,000 1.2 1.2 ×× 10 1066

2.52.5 96,00096,000 7.9 7.9 ×× 10 1055

11 1,000,0001,000,000 5.2 5.2 ×× 10 1055

Page 11: JCCC EwtS 091024 Cloudy

Power-Law DistributionPower-Law Distribution(source: http://www.sdss.org/news/releases/20010605.edr.img9.html)(source: http://www.sdss.org/news/releases/20010605.edr.img9.html)

n ~ D-2.3

diameterdiameter ## impact energy*impact energy*

1 km1 km 11 5.4 5.4 ×× 10 1044 MT MT

100 m100 m 200200 8.3 MT8.3 MT

10 m10 m 40,00040,000 23 kT23 kT

1 m1 m 8,000,0008,000,000 10 tonnes TNT10 tonnes TNT

* http://www.lpl.arizona.edu/impacteffects/

Page 12: JCCC EwtS 091024 Cloudy

Historical Impacts You’ve Heard OfHistorical Impacts You’ve Heard Of

Barringer49 ± 3 ka

Chicxulub64.98 ± 0.05 Ma

Page 13: JCCC EwtS 091024 Cloudy

Historical Impacts You’ve Heard OfHistorical Impacts You’ve Heard Of

Tunguska6/30/1908

Page 14: JCCC EwtS 091024 Cloudy

Craters You Can VisitCraters You Can Visit(source: www.unb.ca/passc/ImpactDatabase/NorthAmerica.html)

Decaturville, MO• 9 miles south of Camdenton on MO-5

• 6 km dia

• < 300 Ma

Odessa, TX• I-20 at exit 108

• 160 m dia

• < 50 ka

Sierra Madera, TX• 18 miles south of Ft Stockton on US-385

• 13 km dia

• < 100 Ma

Page 15: JCCC EwtS 091024 Cloudy

Weaubleau–Osceola StructureWeaubleau–Osceola Structure(source: Dr Kevin Evans, Missouri State University [former SMSU])

• N 37°59’, W 93°38’ (possibly one of series of impacts along 38th parallel, including Decaturville)

• 19 km dia (4th largest in US and one of 50 largest on Earth)

• 340 Ma (middle Mississippian Period)

• impactor diameter ~370 m• ASKC SME is David Neuenschwander

Page 16: JCCC EwtS 091024 Cloudy

Historical Impacts You Historical Impacts You Haven’tHaven’t Heard Of Heard Of

“Clovis Comet” 12.9 ka (http://www.pnas.org/cgi/content/abstract/0706977104v1)

• Tunguska-like event, but much larger, over northeastern North America

• partially destabilized Laurentide Ice Sheet, triggering Younger Dryas cooling; shockwave, thermal pulse, “extensive biomass burning”

• at least 17 species of megafauna went extinct

• Clovis culture disappeared; possible death of 2/3 of North American population

Page 17: JCCC EwtS 091024 Cloudy

Tasman Sea, ~1500 AD (http://www.sciencenews.org/articles/20040306/bob8.asp)

• tsunami left deposits 130 m above sea level in eastern Australia, 150-220 m above sea level on Stewart Island/Rakiura, NZ

• 20 km dia, 150 m deep seafloor crater SW of NZ

• 1-km-wide asteroid impact

Historical Impacts You Historical Impacts You Haven’tHaven’t Heard Of Heard Of

Page 18: JCCC EwtS 091024 Cloudy

Great Chicago Fire, 10/8/1871 (http://pdf.aiaa.org/preview/CDReadyMPDC04_865/PV2004_1419.pdf)

• fragments of Comet 3D/Biela

• also Peshtigo Fire (4,850 km², 1,200-2,500 deaths) and Port Huron Fire (similar size, 50 deaths)

Historical Impacts You Historical Impacts You Haven’tHaven’t Heard Of Heard Of

http://www.cedu.niu.edu/~henning/ChicagoFireWebQuest/fire2.jpg http://www.angelfire.com/mi2/gfmeteor/images/peshtigo1871.jpg

http://upload.wikimedia.org/wikipedia/commons/d/d5/CometBiela.jpg

Page 19: JCCC EwtS 091024 Cloudy

Historical Impacts You Historical Impacts You Haven’tHaven’t Heard Of Heard OfKusaie (Kosrae), 1 Feb 1994 (“Satellites

Detect Record Meteor,” Sky & Telescope, June 1994)

• rocky body 15 meters in diameter traveling 15 km sec-1

• 110-kT explosion at 20 km altitude; visual magnitude -25

• pinpointed by 6 early-warning satellites to 164.1°E, 2.7°N; also seen by two fishermen

• events this size occur about once per decade somewhere on Earth

Most NEOs produce airbursts• volatile cometary material evaporates

• asteroids/meteoroids are often “rubble piles”

• Apollo asteroid 25143 Itokawa

(from Hayabusa probe)

(http://www.lib.utexas.edu/maps/australia/oceania_ref_2007.pdf)

Page 20: JCCC EwtS 091024 Cloudy

Chicago, 26 March 2003 (source:

http://www-news.uchicago.edu/releases/04/040414.parkforest.shtml)

• estimated mass 900 kg; velocity 18 km sec-1

• fireball visible from Michigan, Illinois, Indiana and Missouri

• hundreds of fragments recovered from Chicago’s south suburbs

• KE= ½ mv2 indicates 36,000 kg TNT equivalent

Historical Impacts You Historical Impacts You Haven’tHaven’t Heard Of Heard Of

Page 21: JCCC EwtS 091024 Cloudy

Historical Impacts You Historical Impacts You Haven’tHaven’t Heard Of Heard OfBBC headline,19 December 2004:

“Jakarta shaken by ‘meteor blast’”

• occurred during a terror alert and heightened security (“Operation Candle”)

• audible 60 km away (source: Townsville [Australia] Bulletin/Sun, URL not available)

(source: http://news.bbc.co.uk/2/hi/asia-pacific/4108697.stm)

Page 22: JCCC EwtS 091024 Cloudy

Historical Impacts You Historical Impacts You Haven’tHaven’t Heard Of Heard Of

http://news.nationalgeographic.com/news/bigphotos/52624256.htmlPhotograph by Miguel Carrasco/La Razon/Reuters

Carangas, Peru, 16 September 2007 (source:

http://news.nationalgeographic.com/news/2007/09/070921-meteor-peru.html)

• crater 13 meters across, 3 meters deep

• ejecta thrown 250 meters

Page 23: JCCC EwtS 091024 Cloudy

This Month’s Near-MissThis Month’s Near-Miss(source: http://neo.jpl.nasa.gov/ca/)

asteroid 2009 TU

• flew by at 0.002 AU = 0.8LD shortly before 7 PM CDT on Thu 8 Oct

• H = +27.3; Mv = +13.8; D ≈ 9.1–20m; v = 15.25 km sec-1

• airburst energy would have been ~300 kT (source: http://www.lpl.arizona.edu/impacteffects/)

Page 24: JCCC EwtS 091024 Cloudy

This Month’s Near-MissThis Month’s Near-Miss(source: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009%20TU;orb=1)

Page 25: JCCC EwtS 091024 Cloudy

Effects on Human HistoryEffects on Human History

• mass extinctions

• North American charismatic megafauna

• North American native culture/population

• Younger Dryas origin of diabetes?

Page 26: JCCC EwtS 091024 Cloudy

The Black SwanThe Black Swan

• definition• the Fourth Quadrant• complexity of failure• geopolitical risk

Page 27: JCCC EwtS 091024 Cloudy

The Black SwanThe Black Swan

Definition: “… a large-impact, hard-to-predict, and rare event beyond the realm of normal expectations.”

(source: http://en.wikipedia.org/wiki/Black_swan_theory)

Short version:

low-probability, high-effect events

Page 28: JCCC EwtS 091024 Cloudy

The Fourth QuadrantThe Fourth Quadrant(adapted from http://www.edge.org/3rd_culture/taleb08/taleb08_index.html)

complex (magnitude of effect)

payoffs

Quadrant 3

quite robust to Black Swans

Quadrant 4

LIMITS OF STATISTICS; extreme fragility to Black

Swans

simple

(yes/no) payoffs

Quadrant 1

extremely robust to Black Swans

Quadrant 2

quite robust to Black Swans

application

domain

thin-tailed (Gaussian) probability structure

thick-tailed (power law) probability structure

Page 29: JCCC EwtS 091024 Cloudy

The Complexity of FailureThe Complexity of Failurehttp://www.santafe.edu/research/publications/workingpapers/00-12-062.pdf

http://www.nasa.gov/columbia/home/CAIB_Vol1.html

Page 30: JCCC EwtS 091024 Cloudy

The Fourth Quadrant in ActionThe Fourth Quadrant in Action(source: http://pajamasmedia.com/instapundit/86785/)

http://tipstrategies.com/archive/geography-of-jobs/

Page 31: JCCC EwtS 091024 Cloudy

Geopolitical RiskGeopolitical Risk, or, or

The Meaning of It AllThe Meaning of It All

(with posthumous apologies to Richard Feynman)

Asteroid size distribution and composition combine with terrestrial realities such that:

• rare larger impacts mean frequent smaller impacts

• smaller impact ranges are in the tens of kilotons and are usually airbursts, but …

• so are nuclear weapons, and the explosions look exactly the same, in a world of …

• “hostile capabilit[ies] among various actors with whom we have conflicting interests” (source: http://www.outsidethebeltway.com/archives/2008/04/iran_war_drums_beating/)

Page 32: JCCC EwtS 091024 Cloudy

Global Catastrophic Risk:Global Catastrophic Risk:Taxonomy/OrganizationTaxonomy/Organization

Nature

UnintendedConsequences

HostileActs

Page 33: JCCC EwtS 091024 Cloudy

Global Catastrophic Risk:Global Catastrophic Risk:Observation Selection EffectsObservation Selection Effects

Empirical (A Posteriori) Distribution

A Priori Distribution

Distribution of impact craters, shock glasses, and so on

Distribution of near-Earth objects and Earth-crossing comets

(modified from Global Catastrophic Risks, Table 6.1, page 125)

Beware of anthropic overconfidence bias!

Page 34: JCCC EwtS 091024 Cloudy

Global Catastrophic Risk:Global Catastrophic Risk:Observation Selection EffectsObservation Selection Effects

Empirical (A Posteriori) Distribution

A Priori Distribution

Distribution of impact craters, shock glasses, and so on

Distribution of near-Earth objects and Earth-crossing comets

Human history affected:

North American survivors, diabetics, etc

Human history ended?

Page 35: JCCC EwtS 091024 Cloudy

How to Save CivilizationHow to Save Civilization

Think Globally• detection

• prediction

• mitigation

Act Locally• Powell Observatory• asteroid imaging• orbit refinement• asteroid discovery

Page 36: JCCC EwtS 091024 Cloudy

How to Save Civilization:How to Save Civilization:what what notnot to do to do

“We should act incrementally as prudent risk minimizers and pursue any effective no-regrets options. We do not have to wait for the formulation and acceptance of grand strategies, for the emergence of global consensual understanding, or for the universal adoption of more rational approaches.”

Page 37: JCCC EwtS 091024 Cloudy

DetectionDetectionAutomated searches - telescopes in 0.5-1 m size range

w/CCD cameras:

• Lincoln Near-Earth Asteroid Research (LINEAR) telescope at Socorro, NM

• Near-Earth Asteroid Tracking (NEAT) telescope at Haleakala, Maui, Hawaii

• Spacewatch telescope at Kitt Peak• Lowell Observatory Near-Earth Object Search

(LONEOS) telescope at Flagstaff• Catalina Sky Survey 3 telescopes (2 in Tucson, 1 in

Australia)• Japanese Spaceguard Association (JSGA) telescope in

Japan• Asiago DLR Asteroid Survey (ADAS) telescope in Italy

Page 38: JCCC EwtS 091024 Cloudy

Mitigation – Torino ScaleMitigation – Torino Scale(source: http://neo.jpl.nasa.gov/torino_scale.html)

no hazard white zone 0

normal green zone 1

meriting attention by astronomers

yellow zone 2 – 4

threatening orange zone 5 – 7

certain collisions red zone 8 – 10

Page 39: JCCC EwtS 091024 Cloudy

Powell ObservatoryPowell ObservatoryLewis-Young Park, Louisburg, KSLewis-Young Park, Louisburg, KS

Page 40: JCCC EwtS 091024 Cloudy

Powell ObservatoryPowell Observatory30” Ruisinger Telescope30” Ruisinger Telescope

• Newtonian ReflectorNewtonian Reflector• diameter of aluminized area of mirror = 737 mmdiameter of aluminized area of mirror = 737 mm• focal length = 3760 mm (f/5.1)focal length = 3760 mm (f/5.1)• magnifications 68x – 538x depending on eyepiecemagnifications 68x – 538x depending on eyepiece• details 500’ across on Moondetails 500’ across on Moon

• Light grasp = 11,000 Light grasp = 11,000 × human eye× human eye• limiting visual magnitude = +17limiting visual magnitude = +17• 20 times fainter than Pluto20 times fainter than Pluto• > 100,000,000 stars; thousands of galaxies> 100,000,000 stars; thousands of galaxies• Sun at 8,000 light-yearsSun at 8,000 light-years• activates cone cells in retina – color visionactivates cone cells in retina – color vision

Page 41: JCCC EwtS 091024 Cloudy

ASKC Astro Imaging CenterASKC Astro Imaging CenterPowell Observatory, Louisburg, KS; 38°38'46" N, 94°41'59"

Page 42: JCCC EwtS 091024 Cloudy

Asteroid Imaging CameraAsteroid Imaging Camera

Page 43: JCCC EwtS 091024 Cloudy

Asteroid 2004 QT24Asteroid 2004 QT24PHA (Potentially Hazardous Asteroid); NEO (Near Earth Object)

H = +18.27, diameter ~760 m, period 440 daysEarth MOID = .0074617 AU = 1,116,300 km = 2.9LD

impact energy 23,400 MT (if solid rock at 17 km sec-1)

(source: Dick Trentman, ASKC)

(source: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004%20QT24;orb=1)

Page 44: JCCC EwtS 091024 Cloudy

Asteroid 2004 QT24Asteroid 2004 QT24tracking images taken from Powell Observatory AIC, 4/22/2005

(source: Dick Trentman, ASKC)

Page 45: JCCC EwtS 091024 Cloudy

Asteroid 2004 QT24Asteroid 2004 QT24tracking images taken from Powell Observatory AIC, 4/22/2005

(source: Dick Trentman, ASKC)

Page 46: JCCC EwtS 091024 Cloudy

Asteroid 2004 QT24Asteroid 2004 QT24tracking images taken from Powell Observatory AIC, 4/22/2005

(source: Dick Trentman, ASKC)

Page 47: JCCC EwtS 091024 Cloudy

Asteroid 2004 QT24Asteroid 2004 QT24tracking images taken from Powell Observatory AIC, 4/22/2005

(source: Dick Trentman, ASKC)

Page 48: JCCC EwtS 091024 Cloudy

Saving CivilizationSaving Civilizationthe ASKC Way

1. get nightly list of objects of high interest from MPC2. take 10-100 images of that area of sky3. digitally combine images into 3 groups, “blink” them4. if something jumps, compare with known direction/speed5. astrometric software does position and speed analysis6. send data only (no images) back to MPC 7. they do computation to extend known segment of orbit8. then rate object on Torino scale (0-10)

(source: Mitch Glaze, ASKC)

Page 49: JCCC EwtS 091024 Cloudy

How is this saving civilization?How is this saving civilization?With our data, the Minor Planet Center …

• Updates its library of all known NEOs’ orbital and physical data.• Correlates new discoveries with “lost” asteroids.• Provides accurate predictions of future NEO orbital motion.• Identifies PHAs (potentially hazardous asteroids).• Monitors changes to NEO orbits due to various influences.

Major accomplishments …

• Starting in 2001, Powell became the second most productive observatory in the world (official designation IAUC/MPC #649) for NEO confirmation and tracking.

• In 2004, Powell was specifically requested by the MPC to image “killer asteroid” 2004 MN4, later known as 99942 Apophis, because of the large aperture (30”) Ruisinger telescope and the quality of its previous work.

• Currently, Powell has over 9,300 NEO observations, second only to the federally-funded Lowell Observatory.

(source: AJ Eaton, ASKC)

Page 50: JCCC EwtS 091024 Cloudy

Also, We’ve Discovered A FewAlso, We’ve Discovered A Few

Page 51: JCCC EwtS 091024 Cloudy

… … and here it isand here it is

H = +13.3; Mv = +16.9; diameter ~7.5 km; period 4 yrs 8 mosblackbody surface temperature 235°K, –38°C, –36°Fsurface gravity ≈0.00035 g; 100 lb on Earth = 9/16 oz

(source: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000%20VG38;orb=1;cov=0;log=0#orb)

Page 52: JCCC EwtS 091024 Cloudy

Monday, October 6, 2008Monday, October 6, 2008Humanity’s first successful prediction of an asteroid impact!

Asteroid 2008 TC3• discovered ~20 hours before impact by

Catalina Sky Survey 1.5m telescope on Mt Lemmon, AZ

• 1-5 meters in diameter traveling 12.8 km sec-1; entered atmosphere at 19° angle

• 1-2 kT explosion at 20 km altitude; visual magnitude -13; observed by KLM aircraft crew 1,400 km away; detected by infrasound array in Kenya

• see http://en.wikipedia.org/wiki/2008_TC3 and http://orbit.psi.edu/?q=node/22

Page 53: JCCC EwtS 091024 Cloudy

Impact ImagesImpact Images(http://commons.wikimedia.org/wiki/File:ELG_webcam_record_of_2008_TC3_frame_0005.png)(http://commons.wikimedia.org/wiki/File:ELG_webcam_record_of_2008_TC3_frame_0005.png)

30 seconds beforeduring

20 seconds after

Page 54: JCCC EwtS 091024 Cloudy

Impact AnimationImpact Animation

http://www.youtube.com/watch?v=Cxa2PUluqVU

Page 55: JCCC EwtS 091024 Cloudy

2008 TC3’s Final Orbit2008 TC3’s Final Orbit(source: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2008%20TC3;orb=1)

Page 56: JCCC EwtS 091024 Cloudy

2008 TC3’s Fragments Found!2008 TC3’s Fragments Found!(source: http://www.nature.com/nature/journal/v458/n7237/full/nature07920.html)

• exploded at 37 km altitude; no macroscopic fragments were expected to survive• but 47 meteorites found; total mass 3.95 kg• parent body named Almahata Sitta (“Station Six,” train station with eyewitnesses)• achondrite, a polymict ureilite, ultra-fine-grained and porous, with large

carbonaceous grains• asteroid was F class, made of material so fragile it was not previously represented

in meteorite collections

(source: http://www.sciam.com/article.cfm?id=asteroid-meteorite-sudan-fireball)

Page 57: JCCC EwtS 091024 Cloudy

2008 TC3’s Fragments Found!2008 TC3’s Fragments Found!(source: http://apod.nasa.gov/apod/ap090328.html)

Page 58: JCCC EwtS 091024 Cloudy

Harry Turtledove, Call Your OfficeHarry Turtledove, Call Your Office(source: https://www.cia.gov/library/publications/the-world-factbook/reference_maps/pdf/physical_world.pdf)

actual path

what if?

what if?what if?

Page 59: JCCC EwtS 091024 Cloudy

Join the ASKC!Join the ASKC!What We Do• Monthly meetings with great speakers and knowledgeable club members

• Operate Powell Observatory – training is always available

• Operate Warkoczewski Observatory at UMKC (Friday nights)

• Heart of America Star Party every year at dark-sky site near Butler, MO

What You Get to Do• Members can use the “Louisburg Community Telescope” (actually 2

telescopes, 16” and 12½” reflectors) any time

• Become a “keyholder” at Powell Observatory – training is always available

• Get access to members-only “dark-sky site”

• Help refine asteroid orbits – save civilization!

http://www.askc.org/