Institute for AstronomyHerson BagayMentor : Garry NittaAdvisor : Jeff Kuhn

primary mirror

secondary mirror

spider supports

Optical and mechanical axis

Off-Axis Telescopesecondary mirror

primary mirror

spider support

Optical axis

mechanical axis

Advantages over conventional design

on-axis showing secondarymirror mount and support vanes

off-axis (no obstruction)

M2

Support spiders

Excellent low scattered light imaging

Zero diffraction noise caused by spider vanes

Enabling coronagraphic or high dynamic range observations

Kuhn and Hawley; simulated images from www.beugungsbild.de

clear aperture (off axis) 3-vane support 4-vane support

Big Bear Solar Observatory (1.6 m)

Solar-C Telescope(~0.5 m)

NJSTI; IfA SolarC

Main Project ComponentsPrimary and secondary

mirror mountsInstrumentation

platformSupport

structure/FrameEquatorial tracking

hardware

Design goals

Economically feasibleMaximum deflection must be

minimizedRelative deflection between two areas

in the telescope must be minimum

Optics research3D modeling

software (Autodesk Inventor)

Initial structure conceptualization

Component modeling

Stress and flexure analysis

Design optimization

𝑛1 sin𝜃1 = 𝑛2 sin𝜃2

cos𝛼+cos𝛽= 2cos12ሺ𝛼+𝛽ሻcos12ሺ𝛼−𝛽ሻ

Design Conceptualization

Primary mirrorplatform

Secondary mirror mount

Instrumentation

platform

Optical sensors

Support structure

Equatorial tracking hardware

Shape of structureMain componentsStress points

Telescope mount

basic model

refined model

I-beams, Cylinders and Trusses

Rigidity within the telescope’s full range of motion

Which will provide the least deflection for the same amount of material?

cylinder truss

I-beam

Design variables

diameters

thicknesses

Deflection changes with respect to variable changes

Critical deflection points

relative distance must beremain close to constant

Configuration changes

Supports added

Deflection changes with respect to variable changes

support truss

primary truss

Maximum deflection location lies in one axis

Relative deflection of primary and secondary mirrors are minimized

Equatorial tracking system

Right ascension axis

Declination axis

Design considerationsHeavy – less

vibrationUse of guider

afforded us less constraint on deflection requirement

Stress and strain profile

ConclusionMaximum deflection is minimizedMaximum deflection is minimizedRelative deflection between two critical area Relative deflection between two critical area

is minimizedis minimizedSimple geometric design using simple Simple geometric design using simple

support memberssupport members

Future directionMore realistic simulation – computationally

extensivePart-by-part testingBetter refinement of the model

Special thanks to….- Mr. Garry Nitta, Mr. Jeff Kuhn, Auntie Lani and Bruno at the institute- Nina and Mike

The 2009 Maui Akamai Internship Program is funded by the University of Hawaii, the Department of Business, Economic Development, and Tourism, the National Science Foundation Center for Adaptive Optics (NSF #AST - 9876783)