- V3 Ote Vism V1 V3 Ongin V1 Secondary Focus Tertiary Mirror Fine Steering Mirror Secondary Mirror Focal Surface Primary 1 (558.18 KiB) Viewed 33 times
V3 OTE VISM (V1.V3) ongin V1 Secondary Focus Tertiary Mirror Fine Steering Mirror Secondary Mirror Focal Surface Primary Mirror 1 Component Surface Conic Roc (mm) V1 (mm) V2 (mm) V3 (mm) Phys. Size (mm) concave Primary Secondary Tertiary Fine Steering Milton 158797 1778 9 30162 convex concave flat 09967 . 1 6598 -0 6595 0 71690 -7963 1047 8 0 0 0 0 0 0 -0 19 2 36 66052 738 728 x 517 1725 Figure 2: JWST optics for Problem 2 image? The effective focal length of a telescope is the product of the focal length of the primary mirror and any subsequent magnification of the primary image. Using this, calculate the effective focal length of the primary and secondary combination. c) (5 points) What is the focal length of the tertiary mirror? What is the magnification of the secondary image to the tertiary focus? What is the total magnification of the secondary and tertiary? What is the effective focal length of the complete telescope? d) (5 points) As our next topic in 7C, we will discuss diffraction. For a telescope with an aperture diameter D, diffraction limits the smallest angle that can be resolved to Op ~ 1.222/D, where 2 is the wavelength of the light being observed. For observations at the infrared wavelength of 2 = 2um with the 6.6m diameter primary mirror of the JWST, what is the diffraction limit op? e) (5 points) If we place a CCD camera at the focus of the telescope, what is the approximate size of a CCD pixel (in um) that is matched to op? In order to resolve the diffraction pattern of a distant star and maximize the recovered information, the JWST NIRCAM short wavelength (0.6–2.3um) camera has a pixel size of 18um. How does this compare with the size of the diffraction pattern?