SW250
Sky-Watcher Explorer PDS 250mm Newtonian
Current Operational Coefficient Set
Coefficient Value
Tub1.0040.0080.984
Tu_ubU0.0730.0050.618
Tb_ub0.0610.0020.782
Tbv1.1280.0050.991
Tb_bvB0.0940.0020.867
Tbr1.1600.0050.993
Tb_br0.0730.0030.839
Tv_bvV−0.0140.0020.195
TvrR (BVR)1.2310.0100.976
Tv_vr−0.0250.0030.165
Tr_vr−0.2090.0060.773
Tb_bi0.0330.0090.675
Tbi1.0320.0190.998
Tri0.7710.0160.997
Tr_ri−0.3060.0410.887
Ti_ri−0.0060.0560.002
Tvi1.0150.0200.997
Tv_vi0.0100.0080.181
Ti_viI−0.0040.0260.004
Tr_viR (BVRI)−0.1450.0180.902
Transformation Equations
BandScenarioEquation
BallBs = mB + Tb_bv {[(mB−Bc) − (mV−Vc)] / [1 − Tb_bv + Tv_bv]}
VallVs = mV + Tv_bv {[(mB−Bc) − (mV−Vc)] / [1 − Tb_bv + Tv_bv]}
RBVR
UBVR
Rs = Vs − {(Vc−Rc) + Tvr[(mV−Vc) − (mR−Rc)]}
RBVRI
UBVRI
Rs = mR + Tr_vi [(Vs−Vc) − (Is−Ic)]
IBVRI
UBVRI
Is = Ic + [(mI−Ic) + Ti_vi(Vs−Vc)] / (1 + Ti_vi)
UUBV
UBVR
UBVRI
Us = Uc + [(mU−Uc) − Tu_ub(Bs−Bc)] / (1 − Tu_ub)
Legend: uppercase U, B, V, R, I = standard magnitudes; mU, mB, mV, mR, mI = the untransformed reported magnitude of each frame, before transformation; subscript s = target star (transformed result); subscript c = comparison star, catalogue magnitude (CREFMAG); T = transformation coefficient.
Instrument & Setup
ComponentDescription
TelescopeSky-Watcher Explorer PDS 0.25-m F/4.8 Newtonian
Coma CorrectorBaader MPCC Mark III
CameraZWO ASI533MM Pro CMOS, 3.76 µm pixels
FiltersBaader Bessel UBVRI photometric set