III. 2MASS Details
3. Data Processing
e. Position Reconstruction
Position Reconstruction Technique
Table 1: Pointing Reconstruction Definitions
B-scan = Band scan system (Refers collectively to J-scan, H-scan and/or K-scan) DxJ2H = J-band to H-band cross-scan difference for scan DxJ2H_0 = A priori estimate of J-band to H-band cross-scan difference for scan DxJ2K = J-band to K-band cross-scan difference for scan DxJ2K_0 = A priori estimate of J-band to K-band cross-scan difference for scan DxR1 = U-scan x position difference for Read1 frames DyJ2H = J-band to H-band in-scan difference for scan DyJ2H_0 = A priori estimate of J-band to H-band in-scan difference for scan DyJ2K = J-band to K-band in-scan difference for scan DyJ2K_0 = A priori estimate of J-band to K-band in-scan difference for scan DyR1 = U-scan y position difference for Read1 frames FRAME = Single freeze point during scan (includes J1,J2, H1,H2, K1,K2 frames) H-frame = Refers collectively to H1 and H2 frames H-scan = H-band scan system defined by H2-frame system of first frame of scan H1 = H-band Read1 H1-frame= System attached to each H1 frame (origin at SE corner;+y~N,+x~W) H2 = H-band Read2-Read1 H2-frame= System attached to each H2 frame (origin at SE corner;+y~N,+x~W) HFxHni = H-frame x coordinate H-band source number "i" in FRAME number "n" HFyHni = H-frame y coordinate H-band source number "i" in FRAME number "n" J-frame = Refers collectively to J1 and J2 frames J-frame = Refers collectively to K1 and K2 frames J-scan = J-band scan system defined by J2-frame system of first frame of scan J1 = J-band Read1 J1-frame= System attached to each J1 frame (origin at SE corner;+y~N,+x~W) J2 = J-band Read2-Read1 J2-frame= System attached to each J2 frame (origin at SE corner;+y~N,+x~W) JFxJni = J-frame x coordinate J-band source number "i" in FRAME number "n" JFyJni = J-frame y coordinate J-band source number "i" in FRAME number "n" K-scan = J-band scan system defined by K2-frame system of first frame of scan K1 = K-band Read1 K1-frame= System attached to each K1 frame (origin at SE corner;+y~N,+x~W) K2 = K-band Read2-Read1 K2-frame= System attached to each K2 frame (origin at SE corner;+y~N,+x~W) KFxKni = K-frame x coordinate K-band source number "i" in FRAME number "n" KFyKni = K-frame y coordinate K-band source number "i" in FRAME number "n" N-scan = Nominal scan system (y-axis points N along of-date meridian,+x W) PosFrm = Position-of-Frames processor which reconstructs frame positions PosPts = Position-of-Points processor which reconstructs point-source positions RS = Reference star SXH = Cross-scan scale factor used to convert from H-frame to U-scan SXH_0 = A priori est. of x-scan scale factor to convert from H-frame to U-scan SXJ = Cross-scan scale factor used to convert from J-frame to U-scan SXJ_0 = A priori est. of x-scan scale factor to convert from J-frame to U-scan SXK = Cross-scan scale factor used to convert from K-frame to U-scan SXK_0 = A priori est. of x-scan scale factor to convert from K-frame to U-scan SYH = In-scan scale factor used to convert from H-frame to U-scan SYH_0 = A priori est. of in-scan scale factor to convert from H-frame to U-scan SYJ = In-scan scale factor used to convert from J-frame to U-scan SYJ_0 = A priori est. of in-scan scale factor to convert from J-frame to U-scan SYK = In-scan scale factor used to convert from K-frame to U-scan SYK_0 = A priori est. of in-scan scale factor to convert from K-frame to U-scan TH = Rotation angle of H-band detector array w.r.t. scan direction TH_0 = A priori est. of rot. angle of H-band detector array w.r.t. scan dir. TJ = Rotation angle of J-band detector array w.r.t. scan direction TJ_0 = A priori est. of rot. angle of J-band detector array w.r.t. scan dir. TK = Rotation angle of K-band detector array w.r.t. scan direction TK_0 = A priori est. of rot. angle of K-band detector array w.r.t. scan dir. U-scan = Universal scan system (y-axis along scan path toward ~N; x points ~W) USxHni = U-scan x position of H-band source number "i" in FRAME number "n" USxJCn0 = U-scan x position of J2-frame center for FRAME number "n" USxJni = U-scan x position of J-band source number "i" in FRAME number "n" USxKni = U-scan x position of K-band source number "i" in FRAME number "n" USyHni = U-scan y position of H-band source number "i" in FRAME number "n" USyJCn0 = U-scan y position of J2-frame center for FRAME number "n" USyJni = U-scan y position of J-band source number "i" in FRAME number "n" USyKni = U-scan y position of K-band source number "i" in FRAME number "n" cxR1_0 = A priori est. of Read1 x-scan difference at FRAME zero cyR1_0 = A priori est. of Read1 in-scan difference at FRAME zero dDxJ2H = Small adjustment to J-band to H-band cross-scan difference for scan dDxJ2K = Small adjustment to J-band to K-band cross-scan difference for scan dDyJ2H = Small adjustment to J-band to H-band in-scan difference for scan dDyJ2K = Small adjustment to J-band to K-band in-scan difference for scan dSXH = Small adj. to x-scan scale factor to convert from H-frame to U-scan dSXJ = Small adj. to x-scan scale factor to convert from J-frame to U-scan dSXK = Small adj. to x-scan scale factor to convert from K-frame to U-scan dSYH = Small adj. to in-scan scale factor to convert from H-frame to U-scan dSYJ = Small adj. to in-scan scale factor to convert from J-frame to U-scan dSYK = Small adj. to in-scan scale factor to convert from K-frame to U-scan dTH = Small adjustment to rot. angle of H-band detector w.r.t. scan dir. dTJ = Small adjustment to rot. angle of J-band detector w.r.t. scan dir. dTK = Small adjustment to rot. angle of K-band detector w.r.t. scan dir. dcxR1 = Small adjustment to Read1 x-scan difference at FRAME zero dcyR1 = Small adjustment to Read1 in-scan difference at FRAME zero dmxR1 = Small adjustment to slope of Read1 x-scan difference with FRAME number dmyR1 = Small adjustment to slope of Read1 in-scan difference with FRAME num. dxJ2n = Small adjustment to U-scan x position of J2-frame center for FRAME "n" dyJ2n = Small adjustment to U-scan y position of J2-frame center for FRAME "n" frame = Refers to individual band/read-type combination at freeze point hw = half width of array size mxR1_0 = A priori est. of slope of Read1 x-scan difference with FRAME number myR1_0 = A priori est. of slope of Read1 in-scan difference with FRAME number nf = FRAME number
Return to Section III.3.e.