INAF Osservatorio astronomico di Torino Technical Report nr. 153 Technical description G. Capobianco, G. Massone, S. Fineschi Pino Torinese, 25 th july 2011
2 Index Index... 2 Index of Figures... 2 List f Acronyms... 2 Revision Log... 2 Technical Description... 3 Index of Figures Figure 1 CorMag telescope layout............ 3 Figure 2 CorMag telescope optical layout... 3 Figure 3 CorMag mechanical draw... 5 Figure 4 Spot diagram for different fields... 5 Figure 5 Fraction of enclosed energy... 6 Figure 6 The CorMag telescope... 6 Figure 7 Mechanical assembly of the LCTF. From left: the pre filter, the LCPR and the multistage LC Lyot filter... 7 List f Acronyms CaT CCD CorMag CoT D DFP FS FSR FWHM LCPR LCTF O Cameraa Triplet Charge Coupled Device Coronal Magnatograph Collimator Triplet Detector Detector Focal Plane Field Stop Free Spectral Range Full Width at Half Maximum Liquid Crystals Polarization Rotator Liquid Crystals Tunable Filter Objective Lens Revision Log Date 2011.07.22 Issue 0 Release Released by 0 G..Capobianco Comment First issue
3 Technical Description The CorMag instrument is a spectropolarimeter telescope designed for the detection and the spectropolarimetry of the solar corona FeXIV emission line (530.3 nm) during the total solar eclipses observations. The optical layout is shown in Figure 1 and Figure 2. Figure 1 CorMag telescope layout Figure 2 CorMag telescopee optical layout From the left, the first element is the objective lens (O), an achromatic doublet, after the field stop (FS) there are the collimator triplet (CoT), the Liquid Crystal Tunable Filter (LCTF), the cameraa triplet (CaT) and the detector focal plane (DFP). The properties of the elements are resumed in Table 1. The mechanical draw is in Figure 3. The polarimetric block with the LCTF and the relay optics have a length of 282.9 mm.
4 Focal length[mm]: 800 Objective lens [O] Diameter [mm]: 60 F/# #: 13.3 Collimator triplet [CoT] Liquid Crystal Tunable Filter [LCTF] Camera triplet [CaT] Detector [D] Focal length [mm]: 100 Diameter [mm]: 50 Glasses: N LAF21/SF10/N LAK8 Achromatic designed by Optec LCTF General LCPR Pre filter Length [mm]: 90 Diameter [mm]: 60 Aperture [mm]: 20 Number of stages: 4 FSR [nm]: 2..7 FWHM [nm]: 0.15 Center wavelength [nm]: 528.64 533.38 Tuning step [nm]: 0.01 Manufactur rer: Andover Corp. Center wavelength [nm]: 530.69 FWHM [nm]: 1.89 Manufactur rer: MLO Rotation angles [deg]: 0 180 Focal length [mm]: 100 Diameter [mm]: 50 Glasses: N LAF21/SF10/N LAK8 Achromatic designed by Optec Type: CCD Camera FLI Proline 1001E Sensor: Kodak KAF 1001E Frame size [pixels]: 1024x1024 Pixel size [µm]: 24 A/D Conversion [bit]: 16 Table 1 CorMag single elements specificss
5 Figure 3 CorMag mechanical draw The spot diagram for different fields and the fraction of enclosed energy are reported in Figure 4 and in Figure 5. OBJ: 0.0000, 0.0000 (deg) OBJ: 0.0000, 0.2700 (deg) OBJ: 0.0000, 0.3500 (deg) OBJ: 0.0000, 0.5200 (deg) 0.5303 30.00 IMA: -0.000, 0.000 mm IMA: 0..000, 3.826 mm IMA: 0.000, 4.959 mm IMA: 0.000, 7.367 mm OBJ: 0.0000, 0..8000 (deg) OBJ: 0.0000, 1.0000 (deg) OBJ: 0.0000, -0.2700 (deg) IMA: 0.000, 11.331 mm IMA: -0.000, 14.159 mm IMA: 0.000, -3.826 mmm OBJ: 0.0000, -0.3500 ( deg) OBJ: 0.0000, -0.5200 (deg) OBJ: 0.0000, -0.8400 (deg) OBJ: 0.0000, -1. 0000 (deg) IMA: -0.000, -4.959 mm Surface 5: Tel. field stop IMA: 0. 000, -7.367 mm IMA: -0.000, -11.897 mm Spot Diagram CorMag; FL=800 mm; f/#=13.5 19/07/2011 Units are µm. Airy Radius: 8.752 µm Field : 1 2 3 4 5 6 7 8 9 10 11 RMS radius 2.551 1.590 1.208 0.831 2.328 2.842 1.590 1.208 0.831 2.375 2.842 GEO radius : 3.249 2.523 2.066 1.640 3.710 4.003 2.523 2.066 1.640 4.257 4.003 Box width : 30 Reference : Centroid IMA: 0.000, -14.159 mm CorMag_1b Optec_6_baseline.zmx Configuration 1 of 1 Figure 4 Spot diagram for different fields
6 Diff. Limit 0.0000, 0.0000 (deg) 0.0000, 0.2700 (deg) 0.0000, 0.3500 (deg) 0.0000, 0.5200 (deg) 0.0000, 0.8000 (deg) 0.0000, 1.0000 (deg) 0.0000, -0.2700 (deg) 0.0000, -0.3500 (deg) 0.0000, -0.5200 (deg) 0.0000, -0.8400 (deg) 0.0000, -1.0000 (deg) 1.0 Fraction of Enclosed Energy 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0 2.7 5.4 8.1 10.8 13.5 16.2 18.9 21.6 24.3 Radius From Centroid in µm 27 FFT Diffraction Encircled Energy CorMag; FL=800 mm; f/# =13.5 19/07/2011 Wavelength: Polychromatic Surface: Image (CCD SURFACE) CorMag_1b Optec_6_baseline.zmx Configuration 1 of 1 Figure 5 Fraction of enclosed energy A picture instrument is in Figure 6. Figure 6 The CorMag telescope
7 The mechanical assembly of the LCTF is shown in Figure 7. Figure 7 Mechanical assembly of the LCTF. From left: the pre filter, the LCPR and the multistage LC Lyot filter