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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)
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