When you change the way you look at things, the things you look at change! Night_Sky nircam_logo NIRCam_EPO_patch The James Webb Space Telescope a future space-based observatory NGST_stills_lge science education JWST JWST+NIRCam is Like a Camera http://www.astrosociety.org/education/publications/tnl/50/camera1.html 07-04 fig2 “subsystems” IMG_1036 The camera’s lens is analogous to JWST and collects light. The camera’s components resemble NIRCam. What is the Mission? The mission dictates the design. lWhy would Kodak make a disposable camera? –convenient, portable, lightweight, cheap, simple – –What kinds of pictures would people want to take? lbright sources lday and night (flash) l lWhy do we want a new space telescope? –probe very far back in space & time lobserve the very first stars! ltest the Big Bang model –study origins of planetary systems web_print BangTest Origins: JWST’s 5-10 Year Mission Bolding looking where no one has seen before. poster1 lInfrared response is crucial. l lLook far back in space & time l lPenetrate dust/gas l lSee cool objects lg_jwst_emblem_2004 IR Light Probes Farther in Space & Time Expansion of space “redshifts” light. UV light from the first massive stars should be redshifted to IR. scan screen_full_scale_side_view lTo see the first luminous objects in the Universe requires a new telescope: l –LARGE: to see faint, distant objects – –COLD: to see in the infrared because light from these objects should be highly redshifted – –FAR AWAY: to avoid infrared light from Sun, Earth, & Moon JWST Basics UA is building the near-infrared camera (NIRCam) Launch in 2013 G-2005-0390-028 DSC_43841 jwst_stills_6boom_8 Why Large? Collect light to see faint objects. lJWST – Kodak - eye l lAn opening collects light. llarger à more l lA precision mirror or lens “focuses” light into a sharp image. l lAn instrument records the light. IMG_1863 pupil JWST-HST-primary-mirrors ~2 mm ~8 mm (dark adapted) JWST: 6.5 m ~106x the eye! ~2.5 mm HST: 2.4 m See “inverse-square law” activity in your notebook. Why Cold & Far Away? Our atmosphere absorbs, blurs, & emits background light. An infrared look through the atmosphere on a clear night Turbulence blurs & twinkles starlight Atmosphere emits a background of IR light. sky_background How Far?: 1,000,000 Miles from Earth Lagrange Point #2 esaL2 Lunar transit of Sun seen from STEREO mission An L2-orbit provides continuous viewing and stable temperatures http://antwrp.gsfc.nasa.gov/apod/astropix.html A million miles from planet Earth, last weekend the STEREO B spacecraft found itself in the shadow of the Moon. So, looking toward the Sun, extreme ultraviolet cameras onboard STEREO B were able to record a stunning movie of a lunar transit (aka solar eclipse), as the Moon tracked across the solar disk. Each frame of the movie is a false-color composite of images made through four different filters that highlight temperature regimes and structures in the upper solar atmosphere. In this frame, large bright active regions, seen as dark sunspots in visible light, flank the Moon's silhouetted disk. The Moon appears small, less than 1/4th the size seen from Earth, because the spacecraft-Moon separation is over four times the Earth-Moon distance. Tonight, the Moon will find itself in planet Earth's shadow in a total lunar eclipse. The Eye: A Telescope + Instrument lThe eye has a lens: –to collect light lfrom bright & faint objects –to concentrate (focus) light – lOur eye has detectors (retina): –rods for B/W (120 Mpixel) –cones for color (6 Mpixel) – lDisadvantages of the naked eye: –opening is small –exposure time is short l10 Hz = 0.1 sec –senses only visible light –provides a temporary record pupil eye eyec See “JWST vs. Eye” activity in your notebook. Subsystems of the Human Eye lOptical –image quality –see faint & bright – lElectrical –receive: loperational commands –transmit: ldiagnostic lrelay & store information – lMechanical –stability –pointing –tracking –focusing anatomy_globe visionfigure1 Subsystems of JWST must be packaged into nosecone of rocket l movie: JWST_VR_HQ.mov lUse shift & control keys to zoom jwst_front_view jwst_back_view ariane1 ote2_t Must fit into nosecone of rocket (Ariane 5 ECA) Will launch from European Spaceport in French Guiana. Delicate Equipment “handle with care” lKodak camera: –don’t get shocked –don’t smudge optics – lNIRCam: –fragile materials: loptics (LiF), filters, beryllium bench ldetectors (static sensitive) esdlabels Var-Open-Sm fig_6_1 tpad01 images sign-8_5x12-LG Packaging Camera snaps together with good precision. All optical segments of JWST must align within 100 nanometers. OTEisometric DSC_0061 inner_view IMG_1870 IMG_1039 SHUTTER RELEASE VIEWFINDER FLASH LENS CIRCUIT BOARD Subsystems of Kodak Camera IMG_1038 BATTERY FILM FILM CANNISTER VIEWFINDER FILM ADVANCE NIRCam is One of Four Instruments isim2_t nircam_logo Requirements lMust fit within JWST lMust not exceed mass limits lMust not use or generate too much power Subsystems of NIRCam 13 optical modules 1 Pick-off Mirror assembly 2 Coronagraph 3 First Fold Mirror 4 Collimator lens group 5 Dichroic Beamsplitter 6 Longwave Filter Wheel Assembly 7 Longwave Camera lens group 8 Longwave Focal Plane 9 Shortwave Filter Wheel Assembly 10 Shortwave Camera lens group 11 Shortwave Fold Mirror 12 Pupil Imaging Lens 13 Shortwave Focal Plane 1 10 9 8 7 6 5 4 3 2 11 12 13 Converging light from JWST Every Component is Computer Designed & Modeled Longwave FPA Shortwave FPA Shortwave Fold Mirror First Fold Mirror Collimator Dichroic Longwave Camera (not visible) POM COM Short wave camera PIL SW FWA LW FWA Optical Bench Assembly light-weighted, beryllium not plastic – why? step1 Kinematic mounts Thermal strap OBA_ETU_8591010-007_060413 IMG_1864 Internal Mechanisms opto-mechanical-electrical Alignment Cube Baffles/Covers ICE EIP Electrical Harness & Purge Lines Also: Lift points, harness strain relief, thermal sensors, heaters Gears Optics Shutter Frame counter Flash assembly Winding & takeup mechanism IMG_1864 IMG_1861 IMG_1039 The Shutter Mechanism Does NIRCam use a shutter? lUse your screwdriver to push a small black lever in the area shown to the left until it locks in that position. l lNow you should be able to press the shutter release and watch the shutter move quickly across the hole in the front of the camera. l lEstimate the exposure time. IMG_1051 Focus Alignment Mechanism “linear actuator” FLA4 FLA1 Optics & Mounts special materials & coatings for high throughout lCamera: –Locate the six optical elements? lmain lens, Galilean finder, magnifier, flash optics (2), flash indicator –Measure the focal length of main lens – lMaterials –Plastic l lNIRCam has a unique refractive design –long & short wave channels –dichroic To make a sharp image, both lens surfaces must be precisely shaped and smooth to within 1/20th the wavelength of light. IMG_1050 IMG_1044 IMG_1045 IMG_1861 IMG_1865 IMG_1868 NIRCam Optics & Mounts must be stiff but not stressful Collimator Triplet Dichroic Coronagraphic mask Pick-off mirror Fold flat LW Camera SW Camera Fold flat What is a “kinematic mount”? Requirements: must transmit IR light must have excellent optical quality must work at 40 Kelvin Crystalline materials: Barium Fluoride Lithium Fluoride Zinc Selenide ETU Barium Fluoride Lens ZnSe SW lens NIRCam Optics ZnSe, BaF2, LiF, Fused Silica IMG_9539 IMG_9533 Triplet/Dichroic Mounts must allow cooling without breaking Base Alignment Pins Pad Lens Cell Radial pads Axial pads, spacers, flexures Retainer Bolts .025mm Kapton Neoflon M400H All other Parts Ti-6Al-4V ELI LiF Light Baffles prevent leakage of light from other directions IMG_1860 Alignment Cube Baffles/Covers ICE EIP Electrical Harness & Purge Lines NIRCam: IR Cameras two in each of two modules Full Bench Two adjacent fields of view (2.2 arcminute)2 Both fields in SW and LW bands Two back-to-back imagers Abb2Marien_150inch A single 2048x2048 pixel detector array 4 megaPixels lSurroundings must be cold –35 K –motors etc. would generate IR light – lMiniscule signal levels –microvolts –cable design crucial –Need amplifiers – l“developing” done in software –image processing –see notebook 2x2 FPA in GLS2 a ASIC-FP_assy_photo3 Focal Plane Assemblies mosaiced array: 16 Mpixels Abb2Marien_150inch Kodak’s Detector The film lies on a curved focal plane IMG_1038 BATTERY FILM FILM CANNISTER VIEWFINDER FILM ADVANCE Film has big limitations: ~10% efficient fragile non-linear • fig1 Alignment & Testing must build warm but operate cold lExpansion/contraction –mounts, lenses – lFocus changes l lMotorized mechanisms must work cold –special lubricants? IMG_1869 Marketing & Legacy lKodak camera: –cheap and quick –recycle program –Legacy: lphoto albums of people & families lbring back memories l lJWST: –can’t be recycled –must work from start –Legacy: l“image gallery” of the Universe’s development lchange the way people think Unexpected Applications targets of opportunity lCamera: –astrophotography lbarndoor trackers lunusual long exposures l lJWST/NIRCam: –Discover new objects and phenomena –Conceive new questions about “Origins” – More Related Topics I’m Working on lLens groups –Achromaticity requires combinations of different materials – lCollecting light –Area and light and efficiency – l“Single-point failure” l l“Critical path” l l“Distortion” in images –Tracking and “Star trails” The Science Goals a near-infrared camera is essential young solar system Kuiper Belt Planets The First Light in the Universe: Discovering the first galaxies, Reionization Period of Galaxy Assembly: Establishing the Hubble sequence, Growth of galaxy clusters Birth of Stars and Protoplanetary Systems: Physics of the IMF, Structure of pre-stellar cores, Emerging from the dust cocoon Planetary Systems and the Origins of Life: Disks from birth to maturity, Survey of KBOs, Planets around nearby stars CMB_Timeline150 How to Win at Astronomy adapted from Cosmic Discovery, M. Harwit 108 1600 1700 1800 1900 2000 Sensitivity Improvement over the Eye Year of observations Telescopes alone Photographic & electronic detection 106 104 102 1010 M15center M51alone VenusBlur pupil lDetector arrays l lCeramic Multilayer Board l lWires attached to CMLB using conductive epoxy l lG-11 Strain Relief l lConstantan Wires l 3-mil diameter, PFA Teflon insulation lUralane potting l lMDM connector DSCN0032 Extra Images disposables ote1 observatory1 Extra Images l sagitta2 Extra Images l IMG_1862 IMG_1863 IMG_1870 IMG_1869