low-cost single mirror telescope design …single mirror telescope product design description...

Single Mirror Telescope Product Design Description Document

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Team Z-Telescope 1

Low-Cost Single Mirror Telescope

Design Description Document

Team Z-Telescope

Team Members: Yeyue Chen, Akil Bhagat, Josh Hess

Customer: Jim Zavislan, Professor of Optics at the University of Rochester

Document Number 00010

Revisions Level Date

L 4/27/2016

This is a computer-generated document. The electronic

master is the official revision. Paper copies are for

reference only. Paper copies may be authenticated for

specifically stated purposes in the authentication block.

Authentication Block


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Rev Description Date Authorization

A Initial DDD 2/1/2016 AB

B Updated Optical, Mechanical Design 2/5/2016 AB

C Updates per customer meeting 2/11/2016 JH&YC

-Removed bad starting points

-Updated Spec tables

D More customer updates 2/16/2016 JH&YC

-Mount options added

-Spec table again

-Minor schedule change

E Lens design updates 3/1/2016 YC

F Sensor Test plan, schedule update 3/2/2016 AB

G Lens design updates 3/12/2016 YC

H Lens design updates per customer meeting 3/21/2016 YC

I Schedule Updates 4/4/2016 AB

J Lens design updates per customer meeting 4/23/2016 YC

K Mechanical overhaul 4/25/2016 JH

L Final Edit 4/27/2016 JH&YC

-Moving Forward


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Table of Contents

Vision: 4

Team Responsibilities: 4

Block Diagram: 4

Optical Design 5

Mechanical Design 16

Test Plan / Validation: 19

Risk Assessment: 19

Appendix A: CodeV Full Telescope Specifications 20

Appendix B: Detector Specifications 21

Appendix C: Budget: 21

Appendix D: Specification of Mirror 22

Appendix E: ImageJ Decimation study 23

Appendix F: Schedule 23

Appendix G: Additional Mechanical Pictures 26

Appendix H: Mechanical Bill of Materials 27

Appendix I: Mechanical Drawings 28

Appendix J: Sensor Test Images 29

Intellectual Resources: 30

Reference: 30


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The low-cost single mirror telescope is an internally driven product. As such its design inputs were

derived from Jim Zavislan.

Vision:

A low cost single telescope with a single mirror for planetary observation with a camera instead of an eye.

The main objective is to get young students interested in astronomy/optics. The telescope should be able

to be operated by children 12 years and older. The telescope should use a manual tracking to keep planets

in field of view so multiple images can be taken as the object transits the field of view. Software will stack

multiple images to create a final image of higher quality. A mechanical pointing system should be able to

place naked eye planets in the field of view. The construction of the telescope should be simple enough

that most supplies (not optics) can be purchased at a home improvement store.

Team Responsibilities:

Yeyue Chen: Project Coordinator, Document Handler, Telescope optical design

Josh Hess: Customer Liason, FEM and CAD-Mechanical

Akil Bhagat: Scribe, Testing & Modeling

Block Diagram:

Single Reflector

Telescope

Optical

Single Mirror

Mechanical

Telescope Body

Mounts or Optics

Support for telescope

Manual tracking

Electronic

Sensor

Connection to computer

Image Stacking Software

Power


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Optical Design:

1. Image stacking software example (Keith’s Image Stacking Software)

Figure 1: Examples of what can be accomplished with Keith’s Image Stacking Software.1

2. First Order Analysis and Specifications

a. Equations used during calculation,

f = d / Δθ (1)

2d = 2.44 λ F/# (2)

F/# = f / D (3)

Ds/2 = f * tan (θ/2) (4)

b. Since the telescope is used to observe visible stars, the wavelength range is chosen to

be the visible spectrum (656.27 nm, 587.56 nm and 486.13 nm).

c. We use Microsoft Life Cam hd 3000 as our detector. The Microsoft Life Cam series

use OV9712-1D sensor. The camera costs $22 and can be found on Amazon. The

sensor size is 1280 X 720 with pixel size of 3µm. The detector specifications can be

found in Appendix B.

d. The angular resolution of a diffraction limited system is given by equation (2). At least

two pixels are required to distinguish far away objects into individual images. As we

plug the average wavelength λ = 500 nm and the pixel pitch d = 3 µm into equation (2),

we get that the minimum F/# of our telescope is around 5.

e. The angular diameter of Saturn is 14.5 arc-second, while the angular diameter of Jupiter

is 29.8 arc-second. The Saturn’s ring is composed of multiple smaller rings with gaps

between them. The largest distance between these gaps is named the Cassini’s Division.

It is desired that our telescope is able to resolve the Cassini’s Division, which is 0.7

1 http://keithwiley.com/software/keithsImageStacker.shtml

http://keithwiley.com/software/keithsImageStacker.shtml


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arc-second. According to equation (1) and (3), the larger the F/#, the longer the focal

length, thus the smaller the angular resolution and the narrower the full field of view.

f. The maximum mirror we can get from the machine shop has a 4.25 inches (108 mm)

diameter. With a 3µm pixel pitch sensor and a 4.25 inches aperture diameter, F/5

system gives a 1.146 arc-second angular resolution and a 0.467 degrees full field of

view, while F/8 system gives a 0.716 arc-second angular resolution and a 0.292 degrees

full field of view. A comparison of F/5 and F/8 system can be found in Appendix A.

g. The Strehl ratio is the ratio of peak diffraction intensities of an aberrated vs. perfect

wavefront, which indicates the level of image quality in the presence of wavefront

aberrations. According to the “diffraction-limited criterion”, it is used to define the

maximum acceptable level of wavefront aberration for general observing

conventionally set at 0.80 Strehl.2

h. Any central obstruction would cause a negative effect which is similar to that of

wavefront aberrations. In terms of the conventional aberration limit of 0.80 Strehl, the

maximum acceptable central obstruction size is 0.32D according to equation 53,

omax = [0.5-(0.4/S)]1/2 (5)

For a 4.25 inches (108 mm) diameter mirror, the maximum central obstruction size is

1.36 inches (34.56 mm) diameter. The sensor we use has a 1.55’’ x 1.75’’ dimension.

So an off-axis telescope system is required to avoid the central obstruction effect.

Figure 2: Maximum central obstruction for 0.8 system strehl.

2 http://www.telescope-optics.net/effects1.htm#forms 3 http://www.telescope-optics.net/telescope_central_obstruction.htm

http://www.telescope-optics.net/effects1.htm#forms

http://www.telescope-optics.net/telescope_central_obstruction.htm


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i. For F/8 system, seven field points are analyzed in CodeV

Figure 3: Schematic of the OV9712-1D sensor.

Table 1: Field points we choose to analyze in CodeV

Field points Real Image Height (mm)

x y

Center 0 0

0 0.76

Upper Edge 0 1.08

1.37 0

Right Edge 1.92 0

1.37 0.76

Corner 1.92 1.08

3. Design Process

Obscurations that block portions of the entering beam reduce image contrast and the image

irradiance in reflective system4. There are two methods to avoid obscurations.

a. The first method is to use an eccentric pupil system. System like off-axis Newtonian is

consist of an off-axis mirror segment cut out of a larger paraboloid. All elements are

symmetric about the same axis and the aperture stop is decentered for a clear light path.

We set the Y-radius of the mirror to be -1728 mm to keep the focal length to be 34’’

(4.25’’ at F/8) and start with a 10’’ diameter paraboloid mirror and then place an offset

4 http://photonics.intec.ugent.be/education/ivpv/res_handbook/v2ch18.pdf

http://photonics.intec.ugent.be/education/ivpv/res_handbook/v2ch18.pdf


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aperture to restrict the effective aperture to be 4.25’’ and decenter the aperture stop on

y-axis to make sure the system is unobstructed. The image quality at the center, right

edge, upper edge and corner can be seen below.

Figure 4: Version 1.0 of F/8 Telescope lens schematic.

W A V E F R O N T A N A L Y S I S

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

ZTelescope_F8_Parabolic_V1 POSITION 1

X REL. FIELD 0.00 0.00 0.00 0.71 1.00

0.71 1.00

Y REL. FIELD 0.00 0.70 1.00 0.00 0.00

0.70 1.00

WEIGHTS 1.00 1.00 1.00 1.00 1.00

1.00 1.00

NUMBER OF RAYS 948 948 948 948 948

948 948

WAVELENGTHS 656.3 587.6 486.1

WEIGHTS 1 1 1

FIELD BEST INDIVIDUAL FOCUS BEST COMPOSITE FOCUS

FRACT DEG SHIFT FOCUS RMS STREHL SHIFT FOCUS RMS STREHL

(MM.) (MM.) (WAVES) (MM.) (MM.) (WAVES)

X 0.00 0.00 0.000000 0.041162 0.0002 1.000 0.000000 0.002834 0.0399 0.939

Y 0.00 0.00 0.003103 0.000211

X 0.00 0.00 0.000000 -0.015521 0.0426 0.931 0.000000 0.002834 0.0467 0.917

Y 0.70 0.05 -0.000654 0.000715


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X 0.00 0.00 0.000000 -0.039609 0.0605 0.865 0.000000 0.002834 0.0749 0.801

Y 1.00 0.07 -0.002218 0.000931

X 0.71 0.09 0.000837 0.042266 0.0781 0.786 0.000900 0.002834 0.0882 0.736

Y 0.00 0.00 0.003186 0.000211

X 1.00 0.13 0.001171 0.043330 0.1094 0.623 0.001261 0.002834 0.1172 0.581

Y 0.00 0.00 0.003266 0.000210

X 0.71 0.09 0.000926 -0.014418 0.0882 0.736 0.000899 0.002834 0.0900 0.726

Y 0.70 0.05 -0.000572 0.000715

X 1.00 0.13 0.001349 -0.037442 0.1235 0.547 0.001260 0.002834 0.1305 0.511

Y 1.00 0.07 -0.002058 0.000931

COMPOSITE RMS FOR

POSITION 1: 0.08947

Units of RMS are waves at 546.1 nm.

Figure 5: Diffraction Intensity Spread Function at Field 1 (Center), Field 3 (Upper Edge), Field 5 (Right Edge)

and Field 7 (Corner).

For a full 10’’ F/8 paraboloid mirror, we can see a very good central performance. But

the Strehl Ratio at the corner can only reach 0.511. Off-axis performance is not good

enough for this system. Strehl Ratio above 0.8 can be seen as an acceptable quality.


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We try spherical, parabolic and freeform aspheric mirrors with a shifted stop and find

that spherical and aspheric mirrors would suffer from spherical aberration. The on-axis

performance of a parabolic objective is perfect. But the farther from the parabolic

mirror, the more center-field coma and astigmatism are induced. When aspheric

parameters are added, the best Strehl Ratio we can achieve off-axis is 0.643.

b. The second method is to tilt the mirror. Each element is rotationally symmetric about

its own optical axis. System like Herschelian reflector tilt the primary mirror to bring

the focus out of incoming light and prevent central obstruction effect and the light loss.

However, tilted mirror induces significant image deterioration. To keep aberrations at

an acceptable level, a mirror with long focal length is required.

Off-axis decentered system has better control of aberrations, but is limited in size by price

and production difficulties. Tilted mirror would induce coma and astigmatism, but at

relatively small apertures, the image quality required can be achieved. All central Strehl

Ratio are above 0.8. The worst performance is at the right edge, which has 0.785 Strehl.

The size of aberration is sensitive to changes in the mirror F/#. As we gradually increase

F/#, the angular resolution decreases. But the focal length increases if the aperture diameter

remains constant. The longer the focal length, the larger overall length is required.

For a reflective telescope system, to achieve good image quality with an appropriate mirror

size becomes the major problem. Based on my research, a single aspheric free-form mirror

is capable of forming a perfect geometric image of a single object point. In order to get a

mathematical description of the surface of the mirror, all path length from the object to the

image should be equal. However, just as U.S. Pat. No. 20090009897 described, the stars

we targeted are treated as extended objects, which are “a continuum of object points that

each of which is subject to distortion from perfect imaging by diffraction and optical

aberrations. A single mirror surface is generally not capable of perfect imaging for more

than one object point and image point 5.”

For extended objects, we add additional lenses to correct aberration and shorten the overall

length of the system. More surfaces provide additional degrees of freedom when

optimizing. Aspheric surfaces are more difficult to manufacture than spherical surfaces and

are more complicated to design as part of an optical system.

The optical performance of the system can be improved by making the mirror larger. But

it would cause the size of the whole package grows and cost more money. In order to

balance the overall length of the telescope system and the image performance, we choose

an F/8 system with parabolic mirror as our final design. We purchase the mirror from

Edmund Optics, and the specifications are attached in Appendix D.

5 http://www.google.ch/patents/US20090009897

http://www.google.ch/patents/US20090009897


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4. Final Design

a. Starting Point (110 mm F/7.7 Chief)

Ed Jones’ catadioptric schiefspiegler telescope is a good example of the tilted mirror telescope. It

consists of two PCX and PCV lenses and a single parabolic mirror to correct on and off axis

astigmatism. Off axis coma and lateral color are remained. In order to reduce cost, the correctors

are put after the mirror to minimize the size of lenses.

Figure 6: Ed Jones’ Chief 110 mm F/7.7 telescope6

6 http://www.telescope-optics.net/TCT_2.htm

http://www.telescope-optics.net/TCT_2.htm


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b. Input Data:

Table 2: Lens data input into CODEV

SUR RDY THI GLA

STO -1740 -666 REFLECT

2 INF -3 NBK7

3 -171 -6 --

4 -162 -3.5 NBK7

5 INF -194 --

IMG INF -0.69 --

Table 3: Surface Properties input into CODEV

SUR DCY TLA Type

STO -- -3.9 Bend

2 -- 11.2 Basic

3 -- -- --

4 1.25 -16.2 Basic

5 -- -- Basic

IMG -17 9.1 --

All data listed in Table 2 and 3 are varied when optimizing.

c. After Optimizing (F/8)

Figure 7: Design of an F/8 off-axis telescope with a single parabolic mirror.


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ZTelescope_F8

RDY THI RMD GLA CCY THC GLC

> OBJ: INFINITY INFINITY 100 100

STO: -1635.34718 -643.798674 REFL 0 0

CON:

K : -1.000000 KC : 100

XDE: 0.000000 YDE: 0.000000 ZDE: 0.000000 BEN

XDC: 100 YDC: 100 ZDC: 100

ADE: -2.598931 BDE: 0.000000 CDE: 0.000000

ADC: 0 BDC: 100 CDC: 100

2: INFINITY -6.119368 NBK7_SCHOTT 100 0

XDE: 0.000000 YDE: 0.000000 ZDE: 0.000000

XDC: 100 YDC: 100 ZDC: 100

ADE: 8.444571 BDE: 0.000000 CDE: 0.000000

ADC: 0 BDC: 100 CDC: 100

XOD: 0.000000 YOD: 0.000000 ZOD: 0.000000

XOC: 100 YOC: 100 ZOC: 100

3: -143.49311 -9.046584 0 0

XDE: 0.000000 YDE: 0.000000 ZDE: 0.000000 DAR

XDC: 100 YDC: 100 ZDC: 100

ADE: -1.307678 BDE: 0.000000 CDE: 0.000000

ADC: 0 BDC: 100 CDC: 100

4: -132.75027 -5.926024 NBK7_SCHOTT 0 0

XDE: 0.000000 YDE: -0.019209 ZDE: 0.000000

XDC: 100 YDC: 0 ZDC: 100

ADE: -14.632534 BDE: 0.000000 CDE: 0.000000

ADC: 0 BDC: 100 CDC: 100

XOD: 0.000000 YOD: 0.000000 ZOD: 0.000000

XOC: 100 YOC: 100 ZOC: 100

5: INFINITY -156.668038 100 PIM

XDE: 0.000000 YDE: 0.000000 ZDE: 0.000000

XDC: 100 YDC: 100 ZDC: 100

ADE: 2.043528 BDE: 0.000000 CDE: 0.000000

ADC: 0 BDC: 100 CDC: 100

IMG: INFINITY -0.156994 100 0

XDE: 0.000000 YDE: -12.586079 ZDE: 0.000000 DAR

XDC: 100 YDC: 0 ZDC: 100

ADE: 6.589205 BDE: 0.000000 CDE: 0.000000

ADC: 0 BDC: 100 CDC: 100

XOD: 0.000000 YOD: 0.000000 ZOD: 0.000000

XOC: 100 YOC: 100 ZOC: 100

SPECIFICATION DATA

FNO 8.00000

DIM MM

WL 656.27 587.56 486.13

REF 2

WTW 1 1 1

INI YC

XIM 0.00000 0.00000 0.00000 1.37000 1.92000

1.37000 1.92000

YIM 0.00000 0.75600 1.08000 0.00000 0.00000

0.75600 1.08000

WTF 1.00000 1.00000 1.00000 1.00000 1.00000

1.00000 1.00000

VUX -0.09451 -0.09451 -0.09451 -0.09454 -0.09456

-0.09454 -0.09456

VLX -0.09451 -0.09451 -0.09451 -0.09448 -0.09447

-0.09448 -0.09447

VUY -0.09421 -0.09418 -0.09416 -0.09421 -0.09421

-0.09418 -0.09416

VLY -0.09257 -0.09250 -0.09247 -0.09257 -0.09257

-0.09250 -0.09247

POL N


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APERTURE DATA/EDGE DEFINITIONS

CA

CIR S1 54.000000

REFRACTIVE INDICES

GLASS CODE 656.27 587.56 486.13

NBK7_SCHOTT 1.514322 1.516800 1.522376

SOLVES

PIM

No pickups defined in system

This is a non-symmetric system. If elements with power are

decentered or tilted, the first order properties are probably

inadequate in describing the system characteristics.

INFINITE CONJUGATES

EFL -789.3931

BFL -156.6680

FFL -547.6755

FNO 8.0000

IMG DIS -156.8250

OAL -664.8906

PARAXIAL IMAGE

HT 1.0800

ANG 0.0784

ENTRANCE PUPIL

DIA 98.6741

THI 0.0000

EXIT PUPIL

DIA 142.2241

THI 981.1251

W A V E F R O N T A N A L Y S I S

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ZTelescope_F8 POSITION 1

FIELD BEST INDIVIDUAL FOCUS BEST COMPOSITE FOCUS

FRACT DEG SHIFT FOCUS RMS STREHL SHIFT FOCUS RMS STREHL

(MM.) (MM.) (WAVES) (MM.) (MM.) (WAVES)

X 0.00 0.00 0.000000 0.004214 0.0573 0.879 0.000000 0.004315 0.0573 0.879

Y 0.00 0.00 -0.001173 -0.001177

X 0.00 0.00 0.000000 0.001805 0.0378 0.945 0.000000 0.004315 0.0379 0.945

Y 0.70 0.05 -0.000763 -0.000876

X 0.00 0.00 0.000000 0.001094 0.0299 0.965 0.000000 0.004315 0.0301 0.965

Y 1.00 0.08 -0.000595 -0.000741

X 0.71 0.10 0.000460 0.006154 0.0687 0.830 0.000462 0.004315 0.0687 0.830

Y 0.00 0.00 -0.001247 -0.001166

X 1.00 0.14 0.000642 0.008024 0.0783 0.785 0.000648 0.004315 0.0784 0.785

Y 0.00 0.00 -0.001318 -0.001154

X 0.71 0.10 0.000474 0.003708 0.0533 0.894 0.000473 0.004315 0.0533 0.894

Y 0.70 0.05 -0.000837 -0.000864

X 1.00 0.14 0.000659 0.005258 0.0605 0.866 0.000661 0.004315 0.0605 0.866

Y 1.00 0.08 -0.000768 -0.000725

COMPOSITE RMS FOR

POSITION 1: 0.05730


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Mechanical Design:

Mount:

The telescope will be made from parts that can be found at most home improvement stores. The

body will be mounted into Dobsonian style mount. The Dobsonian mount is essentially putting your

telescope on a hinge to allow for altitude pointing and giving it an axis of rotation for azimuthal pointing.

The current version of the mount is made from ¼” plywood. The azimuthal pointing axis is controlled

by a lazy-susan turntable between the foot of the telescope and the main body. The altitude pointing axis

is controlled by an iron floor flange on the mirror cell and the supporting arms connected by a ½” iron

pipe nipple. The other side of the altitude system is just ½” PVC pipe.

The altitude pointing of the mirror should be stable by designing the center of gravity to be at the hinge

point. However that is not the case with the current iteration of the mount. Design changes were made in

process that changed the center of gravity and made it unstable. This is being addressed in the final

design.

Complete telescope build with additional ND filters to

compensate for sensor saturation. This will be removed in

the final design with more powerful software controlling

sensor integration time.


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Mirror Cell:

The final mirror cell design uses two tip/tilt controls and a tensioner with an offset hinge point instead of

three tip/tilt controls with a central hinge point. This is achieved by using two springs between the mirror

plate and the back of the cell on the tip/tilt controls and one spring on the mirror back pulling the mirror

plate to the back of the cell. There are more pictures in appendix G.

The mirror itself is held to the mirror plate by silicone adhesive. The mirror rests on the heads of all the

bolts to create four points of contact that define a plane. There is a buffer on silicone between the mirror

and the bolt heads. There are four 1” corner brackets on the mirror cell with silicone fed through the hole

adhering the mirror to the corner brackets.

Mirror cell design from garyseronik.com a site

for stargazing enthusiasts. Final Cell Design. H is the hinge

point. T is the tensioner bolt. W is the

tip tilt controls.


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Sensor Arm:

The picture on the left shows the sensor arm with the webcam on the end. The current arm design is a

double layer of ¼” plywood glued and screwed together supported by a wire. This design is not a rigid

as originally thought. The arm vibrates vertically when bumped. The solution is to add another strip of

plywood on the underside of the arm perpendicular to the arm to create a T-beam. This is much more

rigid than the current design.

The webcam mount is shown on the right. The mount is made by stacking and gluing pieces of plywood

to create a part that can slide up and down the sensor arm to adjust the focus. There is a screw in the side

of the mount to lock it into place. The webcam is free to rotate on the mount it came on to help adjust for

manufacturing errors in the arm. The cable is ran down the arm and secured with twist ties.


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Test Plan / Validation:

1. Proof of Concept

a. Once the sensor arrives, the software and sensor will be tested in a makeshift telescope

using mirrors that are readily available at the Institute of Optics. This will allow initial

testing and setup, so that the installation of a custom mirror will be relatively quick and

easy.

2. Prototype assembly

a. Parts needed

i. Final mirror

ii. Sensor

iii. Altered Dobsonian Mount

iv. Mechanical housing

b. Once the final build materials arrive, a working prototype can be assembled and an

attempt to image celestial bodies will be made. The first targets will likely be Venus and

the Moon.

3. Sensor Testing Plan

a. Relative response per pixel

i. Put sensor at output of integrating sphere and take two images at different known

fluxes

1. This allows us to understand variations in the response of the pixels, so

that if images have poor quality we can identify whether the quality issues

are coming from the sensor or the optical system

b. Light level testing

i. Create a test setup in Wilmot to model the amount of light the sensor would

receive from Jupiter over a similar solid angle.

ii. This will ensure that when using the telescope, it is able to receive an adequate

amount of light necessary to actually see the objects we want to see.

c. Image stacking testing

i. Use the images from the simulated low light level testing in an image stacking

software to confirm that the resolution does improve and that the software works

as expected.

Risk Assessment:

The primary risks for this project will be the building and alignment tolerances. Because the telescope is

designed to be built by a 12 year old, it will need to be able to be easily aligned, and small

misalignments or poor assembly pose a very readily foreseeable issue. In order to combat this, the

design of the mechanical housing will be as simple as possible, and the placement and alignment of the

mirror will attempt to be corrected for minor inconsistencies using the sensor.

Moving Forward:

This project will be handed off as a joint venture between the OSA and the University of Rochester’s

makers club. As the original vision was to develop this as a cheap outreach tool for the Institute of

Optics. As such we will develop a package to hand off to the group that make the transition easy.


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Appendix A: CodeV Full Telescope Specifications

Specification Value Unit Comments

Sensor OV9712-1D

Sensor Size = 6.35 mm 1/4 inches = 6.35 mm

Pixel Pitch = 0.003 mm 3 µm = 0.003 mm

Sensor Full VGA Resolution = 1280 X 720 H X V

Sensor Diameter = 4.4058 mm Ds = √(1280^2+720^2) x

0.003 mm = 4.4058 mm

Angular Diameter of Saturn = 14.5 Arc-second

Angular Diameter of Jupiter = 29.8 Arc-second

Ideal Angular Resolution < 0.7 Arc-second "Dawes Limit" (Cassini's

Division)

Wavelength = d, F, C (486.13,

587.56, and 656.27) nm Visible spectrum

Aperture Diameter = 108 mm D = 4.25 inches

F number = 5

Focal Length = 540 mm f = D X F/#

Full Field of View = 28.048 Arc-minute Ds/2 = f * tan (θ/2)

Field points in CodeV = 0, 0.327, 0.467 Degrees Object angle

Actual Angular Resolution = 1.146 Arc-second Δθ = d/f

F number = 8

Focal Length = 864 mm f = D X F/#

Full Field of View = 17.530 Arc-minute Ds/2 = f * tan (θ/2)

Field points in CodeV = 0, 0.205, 0.292 Degrees Object angle

Actual Angular Resolution = 0.716 Arc-second Δθ = d/f


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Appendix B: Detector Specifications

Appendix C: Budget:

Detector

Sensor Size(pixels) 1280x720

Pixels size(um) 3

Camera Microsoft Life Cam hd 3000

Price ~22$

Part Spec Price

Sensor Microsoft Life Cam hd 3000 $22

Software Keith’s Image Stacker $15

Mirror Off-axis parabolic mirror - TBD $450

Lens

Manufacturing Mount materials $45.53

Total < $500


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Appendix D: Specification of Edmund Optics’ 4.25" Diameter x 34" FL Uncoated, Parabolic Mirror

Diameter (mm) 108.0

Diameter (inches) 4.25

Diameter Tolerance (mm) +1.5/-0

Diameter Tolerance (inches) +0.06/-0

Effective Focal Length EFL (mm) 863.6

Effective Focal Length EFL (inches) 34.0

Focal Length Tolerance (%) ±1.5

Aperture (f/#) f/8

Edge Thickness ET (mm) 19.10

Edge Thickness ET (inches) 0.75

Surface Accuracy λ/8

Surface Quality 60-40

Substrate BOROFLOAT®

Coating Uncoated

Back Surface Ground

Type Parabolic Mirror


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Appendix E: ImageJ Decimation study

Original Photo by Voyager 2: 617x480 100x79 Focal Length ~5.5m

75x59 Focal Length ~4 m 50x40 Focal Length 2m

25x19 Focal Length ~1

Process.

1. Take original image (ex 617x480)

into ImageJ.

2. Reduce size of image (ex 100x79)

3. Scale new image to be the same

displayed size.

4. Using h=f*tan(Θ1/2). Where h is half

the larger length of the new

image(ex 100/2 =50=h).

5. The resulting image approximates

the image quality of the calculated

focal length.


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Appendix F: Schedule

Date 2016 Astronomical Event Goal

January Preliminary mirror design

And CAD modeling

February Final optical design and PoC

2/7 Mercury at Greatest Western Elongation

2/14

2/22 Full Moon Explore Mounts

Finalize mount design

March Prototype parts ordered,

Assembly

2/28 Sensor Arrived

3/4 Sensor test station started –

Akil

First mount design finalized -

Josh

Spring

Break

schedule finalized –York,

Akil

First Mount built - Josh

3/9 Final mirror ordered –Group

3/16 Sensor tests concluded –Akil

3/27 Jupiter at Opposition First mirror build complete,

skeleton frame –Group

April Analyze data. Optimize

system, Rebuild system

4/1 Mirror found/ ordered -Josh

4/10 First test -group

4/12 Identify problems with first

build, correct and rebuild

Data analysis –Akil,

Mirror correction –York,

Mount/housing issues –Josh


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4/15 Mercury at Greatest Eastern Elongation Converge on final prototype

–Group

4/22 Full Moon (Pink Moon) Final prototype ready to

present –Group

4/25 Buffer time for last minute

problems

4/28 Design Day


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Appendix G: Additional Mechanical Pictures


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Appendix H: Mechanical Bill of Materials

Quantity Part Price Total

1 2" Corner Brace HD 2 pack 3.97 3.97

1 2'x2'x1/4" plywood 4.92 4.92

1 100 pack Wood screws 6x1/2 3.82 3.82

2 1/2" floor flange 4.53 9.06

1 1/2x1/2 pipe nipple 0.98 0.98

1 1" corner brace 4 pack 2.27 2.27

1 Zinc #10 Washers 1.18 1.18

1 Zinc #10 Internal tooth lock washers 1.18 1.18

1 Zinc #10-32x3" round head machine screw 1.18 1.18

1 Zinc #10-32x3/4" round head machine screw 1.18 1.18

1 Zinc #10-32 cap nut 1.18 1.18

1 Zinc #10-32 Wing nut 1.18 1.18

1 Lazy susan turntable 6" 4.48 4.48

1 DAP auto/Marine Sealant 4.57 4.57

1 Compression Spring 4 pack 4.38 4.38

45.53

Everything was bought at Home Depot. The hardware all comes prepackaged so the quantity is one

package not one piece. For future reference the springs are located in door hardware, the lazy susan in

cabinet hardware, and the sealant in the paint aisles.


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Appendix I: Mechanical Drawings


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Appendix J: Sensor Test Images


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Intellectual Resources:

Jim Zavislan (UR, Optical Engineering) for system help, agreed to help

Paul Funkenbusch (UR, Mechanical Engineering) for FEM and CAD help, agreed to help

Reference:

1. Keith’s Image Stacker


2. Telescope Aberrations: Effects on Image Quality


3. Telescope Central Obstruction: Size Criteria


4. Lloyd Jones, Handbook of Optics, Ch18


5. US Patent 20090009897A1, Wide Field Four Mirror Telescope Using Off-axis Aspherical Mirrors


6. Two-mirror Tilted Component Telescopes 2








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