Small Telescopes, Big Science

Arne Henden

Director, AAVSO

arne@aavso.org

The “big” telescope era

-1970’s

- 4m to 5m class

- public access

- expensive

- manual operation

Courtesy NOAO

Current Status-15+ 8m-class telescopes

-number of specialty telescopes (VISTA, PanSTARRS)

- oversubscribed

Gemini N (NOAO)

VLT (ESO)

Professional Directions

- bigger aperture

- expensive instrumentation

- Chilean location

- expensive operations

- funding? $1,000,000,000 each!

Courtesy Magellan, TMT, ESO

The Opposite Extreme

Courtesy XO, Stare, ASAS

- small apertures, often camera lenses

- wide field, bright stars

- inexpensive

- automated

Science that requires aperture

• Cosmology (dark energy, dark matter, supernovae at Z=2)

• Time resolution on faint objects

• Spectroscopy, especially hi-res

• Adaptive optics

• Infrared observations (flux and weight)

Large Telescope

Instruments

Phoenix

GNIRS

Phoenix

Aperture advantages

• Increased payload capacity

• Increased instrumentation budget

• Good operations support

• Pristine site development

Paranal

Aperture drawbacks

• Expensive

• Site consolidation (Chile!)

• Limited access

• Change of parameter space

• Less funding for smaller telescopes

Small Telescopes?

2-6m = “small”

Worried about closing down these facilities

Expensive to run (often old)

True “Small Telescope” (60cm or less) Advantages

• Inexpensive

• Dedicated

• Can be located anywhere in the world

• Work fine for bright objects

• Can be high cadence (seconds)

• Quality commercial equipment

• Easy to automate

Commercial components

STL (SBIG)

LX-200 (Meade)Prodome

Small Telescope Disadvantages

• You break it, you fix it

• Seldom at pristine site (precious)

• You can’t go cheap

• Details of hardware proprietary

• Small instrument carrying capacity

• Few vendors at the 60cm+ scale

Sonoita Research Observatory

35cm robotic telescope

Used 300 nights/year

Southern Arizona

USD$40000

Ellijay facilities

Small Telescope Alternative

• Refurbish existing telescope

• Established site

• Usually maintenance is available

• Need hardware expertise

• Use commercial products where possible; standard software drivers

Mt. John University Observatory-43d59.2m south, 170d27.9m east, 1031m elevation

Optical Craftsman 60cm

MJUO Optical

Craftsman61cm

Installed in 1970

Refurbished 1979

Computerized 1991

F/16

Lowell/Morgan Telescope

Built in 1960’s by Tinsley; 60cm f/13 Classical Cassegrain

Donated to Lowell Observatory

Used for photographic planetary patrol 1970-1990

Used for CCD observing and personal research in 1990’s

Placed in Steele Visitor Center

Donated to AAVSO 2008

Refurbishment and siting at Dark Ridge Observatory, NM

Will be used for automated photometry, spectroscopy, large instruments

Dark Ridge View

Small Telescope Science

• Lucky imaging

• Asteroids

• Exoplanets

• Variable Stars

Lucky ImagingSmall apertures match Fried parameter

Commercial video cameras have good resolution, subsec exposure capability

Software to register and sift through images available

Russell Hawker; 12-inch

AsteroidsDiscovery space limited; funded surveys like LINEAR, CSS, LONEOS

Many opportunities for light curves

Target of Opportunity, esp. NEO, PHA Courtesy B. Warner

(2008tc3 movie, Nazaret)

ExoplanetsMore than 300 known

About 50 are transiting

Need wide-field system for discovery

Kepler, CoRoT

Follow-up easy, but time consuming

Keck

QuickTime™ and aMPEG-4 Video decompressor

are needed to see this picture.

Fomalhaut NASA

XO

Mercury transit micromag

Exoplanet transits

Vanmunster

0.02mag, 35cm

Discovered by 10cm telescopes

Tonny VanmunsterBelgium2x35cm, CCDCVs, exoplanets

Cindy Foote

Scopecraft 24” and 16”

30 second exposures, Rc

6mmag

Variable Stars

• Every star varies during its lifetime• Physical variation (pulsation, spots) tell us

about stellar structure, cosmology• Geometrical variation (binaries) give us

masses, densities, sizes• Accretion disk phenomena prevalent at all

scales• Transient events (novae, supernovae,

gamma-ray bursts) detail stellar evolution• If you are an astronomer, you will study

variable stars sometime during your career• This is where the AAVSO enters the picture!

Small Telescopes and VSA

• VS Prototypes typically bright• Bright stars easier to observe via

spectroscopy, polarimetry, radio/Xray• Need to know solar neighborhood

before extrapolating to distant galaxies• Need extended observing time for light

curves• Need monitoring for transient events

Examples of projects

• Z UMi - an RCB star

• W Vir - the prototype cepheid

• Z Tau - a Mira

Z UMi - a circumpolar RCB

Real value of SRO is for long-term monitoring of many fields. Note near complete BVRI coverage (dropouts due to summer monsoon) of this circumpolar object. 15:02:01.3 +83:03:49

W Virginis coverage from SRO - one season

W Vir phased light curve, BVRI

Z Tau light curve, SRO

Z T a u

9

1 0

1 1

1 2

1 3

1 4

1 5

1 6

1 7

1 8

2 4 5 0 0 0 0 2 4 5 1 0 0 0 2 4 5 2 0 0 0 2 4 5 3 0 0 0 2 4 5 4 0 0 0 2 4 5 5 0 0 0

J D

Magnitude

A A V S O v i s u a l d a t a

S R O V d a t a

N O F S V d a t a

Z Tau field

USNO 1.55m

The AAVSO

• Dedicated to the study of variable stars• Founded 1911• 1200 members in 45 countries• 3000 total observers (800 active per year)• Both professional and advanced amateur• 15 million online observations• Campaigns, workshops, publications• http://www.aavso.org

History• Harvard photographic sky survey late 1800’s - early

1900’s• Enlisted local Boston amateurs to monitor newly

discovered variable stars• Strong association with Harvard College Observatory -

proam collaboration, AAVSO office at HCO until 1950’s• Moved off-campus 1954, remained in Cambridge• Computerized database in 1960’s• Microcomputers in 1980’s• Web in 1990’s• MySQL, VO, etc. in 2000’s

1918 Meeting

SS Cyg, 1896-2004

HQ - Cambridge, MA (about a mile from Harvard CollegeObservatory/CfA)

AAVSO Staff

Summary

• Big telescopes are not needed for cutting-edge science (try convincing review panels, though!)

• Small telescopes have the advantage that all components are commercially available, software provided

• Even small departments can afford such systems

• Best use is for studying variable stars