presentazione

Document Sample
presentazione Powered By Docstoc
					  Roberto Ragazzoni
  INAF – Astronomical Observatory of Padova
  roberto.ragazzoni@oapd.inaf.it


  Telescope optics
  ASI Headquarter - Rome, January 29th, 2000




 On behalf and with extensive inputs from the Telescope Group (D. Magrin,
D. Piazza, J. Farinato, S. Basso, M. Ghigo, M. Munari, P. Spano’, G. Piotto, E.
 Pace, S. Scuderi, I. Pagano, L. Gambicorti, C. Arcidiacono, R.U. Claudi, V.
      Viotto, M. Dima, G. Gentile, R. Canestrari, S. Desidera, S. Benatti)
Timeline…
   ESTEC 2nd June 2008: claimed a new optical design is
    possible and useful
   First telescope group meeting end of 28th Aug. 2008
   Meeting in ESTEC, 9th Sept. 2008
   Meeting in Bern 24th Sept. 2008
   Second telescope group meeting, 25th Sept. 2008
   Third telescope group meeting, 18th Nov. 2008
   ESTEC meeting 28th Nov. 2008

   7 meetings, various optical design, always a current optical
    design…
   In the last ESTEC meeting decision to trace a new baseline
    with an all-refractive, 14..15arcsec/pixels scale!!!
    Requirements and design drivers

    Payload Definition Document (PDD)
   Spectral Range    > 500 m
   Field of view     ≥ 500 degree2
   PSF size          90% en-squared energy  2×2 pixel2
                      PSF Flat-topped (defocused)
   Collecting Area   ~ 100 cm2 × 28 telescopes
                      EPD ~ 112.8 mm
                      EPD unique telescope ~ 597 mm
   Plate scale       12.5 arcsec/pixel
   Detector format   3584×3584×4
   Pixel size        18 m
                    ESTEC Optical Design

                     809 mm
                                                             Spectral Range    400 – 1000 m
                                L1
            M2                                               Field of view     <634 degree2
                               Silica
           SiC
         Aspheric
                              Aspheric                       Image quality     90% EE  2x2 pixel2
          (Stop)                                                                NO PSF Flat-topped
                                                    FPA
                                                             Collecting Area   ~83-105 cm2
412 mm




                                                                                (Vignetting)
                                            L2
                                           BK7               Plate scale       12.5 arcsec/pixel
                                         Aspheric
                                                             Optical elements 5.91 Kg
                                                              mass

                                           M1                FPA size          130 mm
                                           SiC
                                         Aspheric
                    ESTEC Optical Design

                     809 mm
                                                             Spectral Range    400 – 1000 m
                                L1
            M2                                               Field of view     <634 degree2
                               Silica
           SiC
         Aspheric
                              Aspheric                       Image quality     90% EE  2x2 pixel2
          (Stop)                                                                NO PSF Flat-topped
                                                    FPA
                                                             Collecting Area   ~83-105 cm2
412 mm




                                                                                (Vignetting)
                                            L2
                                           BK7               Plate scale       12.5 arcsec/pixel
                                         Aspheric
                                                             Optical elements 5.91 Kg
                                                              mass

                                           M1                FPA size          130 mm
                                           SiC
                                         Aspheric

                                               Still baffling undoable and performances
                                               far from the published one from the .Zmx
                                            files we have got so far (9th Sept. and later).
                                               We now think this is unrelevant today
                            Refractive Optical Design

                                 437 mm
                                                                 Spectral Range     500 – 900 m
           L1
          CaF2
                                                                 Field of view      550 degree2
                                               L5
         Aspheric      L2      L3      L4     CaF2               Image quality      90% EE  2×2
                    S-TIM35 S-LAH79   CaF2   Aspheric             pixel2             NO PSF Flat-topped
                                                                 Collecting Area    100 cm2
192 mm




                                                                                     EPD ~ 112.8 mm
                                                        FPA
                                                                 Plate scale        11.8 arcsec/pixel
                                                                 Optical elements 5.24 Kg
                          Stop                                    mass
                                                                 FPA size           129 mm
                                                                 Field Distortion   4.52%
                            Refractive Optical Design

                                 437 mm
                                                                 Spectral Range     500 – 900 m
           L1
          CaF2
                                                                 Field of view      550 degree2
                                               L5
         Aspheric      L2      L3      L4     CaF2               Image quality      90% EE  2×2
                    S-TIM35 S-LAH79   CaF2   Aspheric             pixel2             NO PSF Flat-topped
                                                                 Collecting Area    100 cm2
192 mm




                                                                                     EPD ~ 112.8 mm
                                                        FPA
                                                                 Plate scale        11.8 arcsec/pixel
                                                                 Optical elements 5.24 Kg
                          Stop                                    mass
                                                                 FPA size           129 mm
                                                                 Field Distortion   4.52%



Lighter, more compact, same performances, thermal main concern!
                    New Requirements

    Optics specifications: V 2.0, October 27th, 2008,
    Lucien Hill, Patrick Levacher
   Spectral Range     450-1000 m      (400 – 1100 m)
   Field of view      ≥ 500 degree2    (132x132 mm2, 133x133 mm2)
   PSF size           range +/-50 m
                       90% EE diameter < 30 arcsec
                       90% EE diameter > 30 m (20 arcsec) cross sections
   Collecting Area    ~ 110 cm2 x 30 telescopes
                       EPD ~ 118.7 mm
                       EPD unique telescope ~ 650 mm

   Plate scale        ≤ 12.0 arcsec/pixel (Variation < 10%)
   Field Distortion   < 1%
                       (stability<0.1% over the Temperature range)
   Detector format    3584x3584x4
   Pixel size         18 m
               “New” Refractive Optical Design

                               421 mm                      Spectral Range     450 – 1000 m
           L1
          BaF2                              L5             Field of view      550 degree2
         Aspheric       L3       L4      N-LAK22
                 L2                                        Image quality      90% EE  2.5×2.5 pixel2
                     N-PK52A    BaF2     Aspheric
               LAFN7
                                                           Collecting Area    100 cm2
                                                                               EPD ~ 112.8 mm
186 mm




                                                    FPA    Plate scale        11.99 arcsec/pixel
                                                           Optical elements 5.63 Kg
                                                            mass
                    Stop                                   FPA size           132 mm
                                        13 mm              Field Distortion   3.17%
Mechanical design
(Bern contribution)
Mechanical design
(Bern contribution)
Based on preliminary tolerance analysis
with an overall image quality deterioration
by no more than 30% of the nominal value.


 Mechanical design
 (Bern contribution)
Lines Of Sight
Telescopes field Overlap
              Telescope scale ~ 12.5 arcsec/px
              -> Telescope Field f=24.9° side
              Configuration Total field side (2-k)f
              K= overlapping factor
                  K=1 -> 1 LOS ->Total field side =f
                  K=0-> 4 LOS ->Total field side =2f
It is movie time…
New “ESTEC-29-Nov” baseline

   Plate scale of 14..15arcsec/pixel

   Aperture of full 120mm

   Coverage on CCD of 132mm in size

   800 square degrees of Field of View

   90% of EE in 2x2 pixel
                15 arcsec/pixel – 6 lenses


            394 mm              Spectral Range     450 – 1000 m
                                Entrance Pupil Diameter 120 mm
                                F/#                2.06 @ 700 m
                                Field of view      28.64 × 28.64 degree2
225 mm




                             FPA over FPA 129 mm = 786 degree2
                                                             2
                                 over FPA 132 mm = 820 degree
                                Image quality      80% EE  2×2 pixel2
                                                    90% EE  2.5×2.5 pixel2
         Stop
                                Plate scale        15 arcsec/pixel
                                Lens glasses       Schott catalogue
                                                    RadHard

         Aspheric surfaces      Optical elements < 7.5 Kg
                                 mass
                                Optimization FPA size      132 mm
                                Field Distortion   4.61%
(Preliminary) conclusions

   New optical design with an additional lens
    are ready
   14..15 arcsec/pixel dilemma??
   Optical quality definition??
   Which is the “current” baseline??
   When can we really freeze the design??
   Frozen specifications needed!!!

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:3
posted:9/29/2011
language:English
pages:17